Latest / Luke's English Podcast / Scientists Just Measured Something QUANTUM Inside Your Brain

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Scientists Just Measured Something QUANTUM Inside Your Brain · Luke's English Podcast

0:00
Speaker 1: In 1997, a surgeon poured liquid xenon over an exposed
0:05
Speaker 1: strip of human cortex, and the patient stopped dreaming in
0:10
Speaker 1: 11 seconds. Not slowly, not gradually. 11 seconds, and whatever
0:17
Speaker 1: had been happening inside that mind went dark. Tonight you
0:22
Speaker 1: will meet a robin whose eye contains a quantum compass
0:27
Speaker 1: Built from the spin of a single electron and a
0:30
Speaker 1: temple of hollow protein tubes inside every neuron that may
0:34
Speaker 1: be running calculations, physics insists warm matter cannot run. You
0:41
Speaker 1: will also hear about a cave in Arizona where a
0:44
Speaker 1: man breathed anesthetic gas and woke up certain he had
0:50
Speaker 1: touched the boundary of something he had no words for.
0:55
Speaker 1: And there is much more waiting after all of that.
0:58
Speaker 1: The question underneath everything is this. If quantum coherence has
1:03
Speaker 1: been measured in a leaf in a robin, and now
1:06
Speaker 1: in brain proteins, is the warm, wet human brain the
1:11
Speaker 1: only quantum computer that has ever actually worked? Or is
1:16
Speaker 1: consciousness purely classical? Before we begin, if you enjoy these
1:21
Speaker 1: topics as much as we do, Make sure to like
1:25
Speaker 1: the video and subscribe. It's a simple action, but it
1:28
Speaker 1: helps this channel reach more curious minds like yours. Now
1:33
Speaker 1: let's begin. Nineteen molecules walk into a laboratory and they
1:39
Speaker 1: share almost nothing. One is a noble gas that does
1:45
Speaker 1: not react with anything. One is a laughing gas used
1:49
Speaker 1: by dentists. One is an ether that smelled up operating
1:53
Speaker 1: rooms for a century. One is a fluorinated compound engineered
1:59
Speaker 1: in a chemistry lab decades after the others were discovered.
2:04
Speaker 1: Different shapes, different sizes, different electrical charges, different melting points,
2:11
Speaker 1: different everything. And yet every single one of them switches
2:15
Speaker 1: off human consciousness completely. at almost exactly the dose you
2:20
Speaker 1: would predict from a single physical property that has nothing
2:24
Speaker 1: obvious to do with the brain. That property is how
2:29
Speaker 1: well they dissolve in olive oil. Charles Ernest Overton was
2:36
Speaker 1: a German-British pharmacologist working in the early 1900s, a careful
2:42
Speaker 1: and methodical man who did not like mysteries left on shelves.
2:48
Speaker 1: He was not trying to solve consciousness when he began
2:51
Speaker 1: his experiments. He was trying to understand why tadpoles went
2:56
Speaker 1: limp when you exposed them to certain organic compounds, and
3:00
Speaker 1: he was trying to find the pattern, if there was one.
3:04
Speaker 1: In 1901, he published a systematic comparison of anesthetic potency
3:10
Speaker 1: across a wide range of molecules, and what he found
3:14
Speaker 1: stopped him. The single best predictor of whether a molecule
3:18
Speaker 1: would put a tadpole to sleep was not its size,
3:21
Speaker 1: not its electrical charge, not its reactivity. It was the
3:26
Speaker 1: ratio of how readily the molecule dissolved in oil versus
3:30
Speaker 1: how readily it dissolved in water. Dissolves well in oil
3:34
Speaker 1: works as an anesthetic. Does not dissolve well in oil
3:38
Speaker 1: does not work. The correlation was so clean and so
3:42
Speaker 1: strange that, that Overton did not quite know what to
3:45
Speaker 1: make of it, and neither did anyone else. A German
3:50
Speaker 1: pharmacologist named Hans Meyer had arrived at the same finding
3:55
Speaker 1: independently the same year, and so the relationship was named
3:59
Speaker 1: the Meyer-Overton correlation, and then, for most of the twentieth century,
4:04
Speaker 1: essentially set aside, the correlation has not weakened with time,
4:09
Speaker 1: it has strengthened. Across roughly a hundred structurally unrelated molecules,
4:15
Speaker 1: the Meyer-Overton correlation holds with a correlation coefficient above 0.98.
4:23
Speaker 1: That is an extraordinarily tight relationship for biology, where systems
4:28
Speaker 1: are messy and exceptions are common. The correlation says that
4:33
Speaker 1: lipid solubility predicts anesthetic potency almost perfectly, regardless of what
4:39
Speaker 1: the molecule actually looks like or does chemically. That should
4:44
Speaker 1: be impossible if the story were simple. If anesthetics worked
4:49
Speaker 1: by binding to a specific protein receptor the way most
4:52
Speaker 1: drugs do, you would expect molecular shape to matter. You
4:57
Speaker 1: would expect chemical reactivity to matter. You would expect the
5:02
Speaker 1: lock and key specificity that pharmacology is built on. Instead,
5:08
Speaker 1: you get this strange, elegant, almost law-like connection to oil.
5:15
Speaker 1: Xenon makes this concrete in a way nothing else does.
5:21
Speaker 1: Xenon is a noble gas. It has a full outer
5:24
Speaker 1: electron shell. It does not form chemical bonds under normal conditions.
5:30
Speaker 1: It does not react with proteins. It does not react
5:34
Speaker 1: with lipids. It does not react with water. It is,
5:39
Speaker 1: chemically speaking, one of the most inert substances in the
5:43
Speaker 1: known universe, and yet breathe enough of it, specifically at
5:48
Speaker 1: around 71% of one atmosphere of pressure, and you will
5:54
Speaker 1: lose consciousness just as completely as you would under any
5:58
Speaker 1: other general anesthetic. Xenon dissolves in olive oil. That is
6:05
Speaker 1: the only chemical property it shares with with halothane, with isoflurane,
6:11
Speaker 1: with nitrous oxide, with the entire pharmacological family of molecules
6:17
Speaker 1: that together define the anesthetic state. Something deeply strange is happening,
6:23
Speaker 1: and it has been happening in every operating room in
6:25
Speaker 1: the world for over a century without a satisfying explanation.
6:31
Speaker 1: The modern answer that textbooks give is that anesthetics act
6:36
Speaker 1: on specific ion channel receptors, particularly the GABA-A receptor, which
6:42
Speaker 1: normally responds to the inhibitory neurotransmitter GABA, and the NEMDA receptor,
6:49
Speaker 1: which is involved in excitatory signaling. These receptors are real,
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Speaker 1: their involvement in anesthesia is real, and modulating them does
7:00
Speaker 1: produce sedation. But these receptor mechanisms cannot be the whole story,
7:05
Speaker 1: because xenon does not bind GABA-A or NEMDA receptors through
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Speaker 1: the same sites that other anesthetics use. Its mechanism is different.
7:16
Speaker 1: And yet its potency is perfectly predicted by the Meyer-Overton correlation,
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Speaker 1: the same as all the others. The receptor theory explains
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Speaker 1: some of the pharmacology. It does not explain the patterns.
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Speaker 1: a 2021 paper in the journal Anesthesiology by Emerson and
7:36
Speaker 1: colleagues pushed the question somewhere more unsettling. The team looked
7:42
Speaker 1: not at receptors, but at what xenon does to the
7:46
Speaker 1: electrons inside aromatic amino acid rings, the ring-shaped molecular structures
7:53
Speaker 1: found in amino acids like tryptophan and phenylalanine. These rings
7:59
Speaker 1: contain electrons that are delocalized, spread across the ring rather
8:04
Speaker 1: than pinned to individual atoms, and those electrons can participate
8:09
Speaker 1: in the kind of quantum tunneling and coherence that classical
8:13
Speaker 1: chemistry does not accommodate. What Emerson and colleagues found was
8:19
Speaker 1: that xenon preferentially slows the dynamics of those delocalized electrons.
8:26
Speaker 1: not by binding to a receptor, not by blocking a channel,
8:30
Speaker 1: by altering the quantum mechanical behavior of electrons inside protein structures.
8:36
Speaker 1: That is a different kind of pharmacology entirely. But that
8:40
Speaker 1: is not the strange part. The strange part had already
8:45
Speaker 1: been discovered in 1950 and then mostly forgotten. Two researchers
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Speaker 1: named Johnson and Flagler were working with tadpoles. The same
8:57
Speaker 1: animal Overton had used half a century earlier, and they
9:01
Speaker 1: found that if you anesthetize a tadpole and then put
9:05
Speaker 1: it under very high hydrostatic pressure, the pressure partially reverses
9:10
Speaker 1: the anesthesia. The tadpole wakes up, or at least becomes
9:15
Speaker 1: more responsive, while still saturated with the anesthetic molecules. This
9:21
Speaker 1: pressure reversal does not change the lipid solubility of the anesthetic.
9:25
Speaker 1: It does not wash the drug out. It does not
9:28
Speaker 1: alter the concentration in the tissue. It reverses the effect anyway,
9:33
Speaker 1: which means the lipid solubility is not the direct mechanism.
9:38
Speaker 1: It is a proxy for something else, something structural, something
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Speaker 1: that pressure can undo. What pressure does to proteins is
9:48
Speaker 1: squeeze their internal geometry. It compresses the spaces inside folded structures.
9:55
Speaker 1: It alters the conformational flexibility of molecules that depend on
10:00
Speaker 1: having room to move between states. If the anesthetic effect
10:05
Speaker 1: depended on a protein being able to shift between two
10:08
Speaker 1: physical configurations, pressure would resist that shift. The tadpole would
10:14
Speaker 1: wake up. And it does. The molecule that erases you
10:19
Speaker 1: is doing something to your neurons that classical chemistry cannot
10:23
Speaker 1: fully describe. And that gap, that narrow and troubling gap
10:29
Speaker 1: between what the correlation predicts and what the receptor theory explains,
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Speaker 1: is where this whole night begins. To understand what anesthetics
10:40
Speaker 1: might actually be disrupting, you need to go inside a
10:44
Speaker 1: single neuron and find the structure that Stuart Hameroff an
10:49
Speaker 1: anesthesiologist working in Tucson, became obsessed with in 1987, a
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Speaker 1: tube so small that quantum effects are not forbidden but expected.
11:02
Speaker 1: That tube is not a metaphor. It is a physical object,
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Speaker 1: a hollow cylinder of protein, seven nanometers across, running through
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Speaker 1: the interior of every neuron in your brain right now
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Speaker 1: in numbers approaching a billion per cell. It vibrates. It conducts.
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Speaker 1: And for 30 years, the question of whether it thinks
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Speaker 1: has divided the people who study it almost as cleanly
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Speaker 1: as the molecules that first revealed the problem divided consciousness
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Speaker 1: from whatever comes after it. What Johnson and Flagler found
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Speaker 1: in 1950 pointed toward something geometry- dependent inside neurons, something
11:49
Speaker 1: that pressure could squeeze back into a different state. The
11:53
Speaker 1: aromatic amino acid rings that Emerson's team identified in 2021
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Speaker 1: are part of that same interior geometry. They are the
12:04
Speaker 1: places where electron dynamics slow under anesthetic exposure, where quantum
12:10
Speaker 1: tunneling becomes the language used and classical binding becomes insufficient
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Speaker 1: as a translation. Overton never knew about quantum tunneling. He
12:21
Speaker 1: was working with olive oil and tadpoles in a garden
12:25
Speaker 1: laboratory in Basel, measuring how fast molecules crossed a membrane,
12:31
Speaker 1: and he found a number so regular across so many
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Speaker 1: substances that it should have launched a research program lasting generations. Instead,
12:41
Speaker 1: it was filed, named and left on a shelf while
12:46
Speaker 1: pharmacology moved toward receptors and channels and the satisfying machinery
12:52
Speaker 1: of lock and key. The lock and key model is
12:56
Speaker 1: real and useful and explains a great deal. It simply
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Speaker 1: does not explain xenon. It does not explain pressure reversal.
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Speaker 1: It does not explain why electron dynamics inside aromatic rings
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Speaker 1: slow at exactly the doses that silence a mind. Those
13:17
Speaker 1: three facts together form a shape, and the shape is
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Speaker 1: not classical. The molecule that erases you is operating at
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Speaker 1: a level that classical chemistry can approach, but not quite reach.
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Speaker 1: And the structure it may be reaching into The structure
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Speaker 1: Hameroff spent his career describing is waiting one chapter further in,
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Speaker 1: inside the neuron, inside the protein, inside the geometry, that
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Speaker 1: pressure can compress and taxol can freeze and anesthetics, apparently,
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Speaker 1: can quiet. Inside every neuron in your brain right now,
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Speaker 1: there are roughly a billion hollow protein tubes. each one
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Speaker 1: 7 nanometers wide, and for 30 years the scientists who
14:10
Speaker 1: studied them could not agree on whether they were the
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Speaker 1: brain's skeleton or something far stranger. 7 nanometers is almost nothing.
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Speaker 1: It is smaller than most viruses. You could stack 10,000
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Speaker 1: of these tubes across the width of a human hair.
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Speaker 1: And yet they vibrate at frequencies that reach into the
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Speaker 1: terahertz range, which is the frequency band that sits between
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Speaker 1: microwave radiation and infrared light, and they do this constantly,
14:44
Speaker 1: at body temperature, inside every one of the roughly 86
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Speaker 1: billion neurons in your brain. The scaffolding explanation said they
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Speaker 1: were there to give the cell its shape, to act
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Speaker 1: as internal highways along which molecular cargo could travel. That
15:02
Speaker 1: explanation was clean and satisfying, and it was almost certainly incomplete.
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Speaker 1: The structure itself is worth understanding, before anything else. Microtubules
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Speaker 1: are built from a protein called tubulin, and tubulin comes
15:19
Speaker 1: in two slightly different forms, called alpha and beta, that
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Speaker 1: lock together into a unit called a dimer. Each dimer
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Speaker 1: is about 8 nanometers long, These dimers assemble end-to-end into
15:35
Speaker 1: long strands called protofilaments, and 13 protofilaments wind around each
15:42
Speaker 1: other to form the hollow cylinder of the microtubule. The
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Speaker 1: result is a tube with a geometry that is not accidental.
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Speaker 1: The way the dimers pack together creates a helical lattice,
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Speaker 1: a spiral pattern that repeats with mathematical regularity along the
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Speaker 1: length of the tube. and that regularity extends not for
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Speaker 1: a few nanometers, but for micrometers, which in the world
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Speaker 1: of molecular biology is an enormous distance. Electron microscopy studies
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Speaker 1: taken at nanometer resolution confirmed something important about this lattice.
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Speaker 1: It is not disordered. It is crystalline. Long-range crystalline order
16:27
Speaker 1: stretching across distances is that dwarf the individual components, and
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Speaker 1: that kind of order is the prerequisite for any coherent
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Speaker 1: physical process. A single neuron contains roughly 100 million tubulin dimers.
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Speaker 1: That is the number 10 followed by eight zeros. Think
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Speaker 1: about what that means for computation. The synaptic connections a
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Speaker 1: neuron makes with its neighbor's number in the thousands, perhaps
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Speaker 1: tens of thousands, for the most connected cells. The surface
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Speaker 1: area of computational elements represented by tubulin dimers in that
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Speaker 1: same neuron exceeds the synaptic count by several orders of magnitude.
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Speaker 1: Whatever is happening on the microtubule lattice, it is happening
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Speaker 1: on a surface so large that the synapses, for all
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Speaker 1: their importance, are a thin annotation written on a much
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Speaker 1: larger page. Stuart Hameroff did not come to microtubules through
17:37
Speaker 1: cell biology. He came through anesthesia, which is a different
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Speaker 1: entrance entirely. Hameroff is an anesthesiologist, and in the mid-1980s
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Speaker 1: he was at the University of Arizona in Tucson, asking
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Speaker 1: the same question that Charles Overton had asked in 1899
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Speaker 1: and that nobody had fully resolved since. Why do anesthetics work,
18:04
Speaker 1: not at the receptor level, which was already reasonably well described,
18:09
Speaker 1: but at the level of what they are actually touching
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Speaker 1: when they extinguish awareness? He began reading the cell biology
18:17
Speaker 1: literature and encountered microtubules, and what he noticed was was
18:22
Speaker 1: that the same drugs that disrupted microtubules also interfered with
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Speaker 1: awareness in ways that did not fit cleanly into the
18:31
Speaker 1: receptor story. In 1987, he published a book called Ultimate Computing.
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Speaker 1: The title was not modest. The argument was that microtubules
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Speaker 1: were the brain's computational substrate, not a passive scaffold but
18:49
Speaker 1: an active information processing system, and that the geometry of
18:54
Speaker 1: the tubulin lattice made it capable of doing something beyond
18:59
Speaker 1: classical bit flipping. The classical version of the idea is
19:03
Speaker 1: already interesting. Each tubulin dimer can exist in two slightly
19:09
Speaker 1: different physical configurations, two conformational states, determined by the orientation
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Speaker 1: of its alpha and beta subunits relative to each other.
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Speaker 1: If you assign a zero to one state and a
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Speaker 1: one to the other, you have a bit. One hundred
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Speaker 1: million bits per neuron arranged in a crystalline lattice with
19:34
Speaker 1: defined neighbor relationships is already a remarkable computational resource. But
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Speaker 1: Hameroff's proposal did not stop at classical bits. The geometry
19:47
Speaker 1: of the lattice The way the dimers are spaced and oriented,
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Speaker 1: also allows something else. A dimer does not have to
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Speaker 1: be in one state or the other. Quantum mechanics permits
20:00
Speaker 1: it to be in both states simultaneously, what physicists call
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Speaker 1: a superposition, and the lattice geometry means that the superpositions
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Speaker 1: of neighboring dimers can become correlated, which is the beginning
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Speaker 1: of quantum coherence. For most of the two decades after
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Speaker 1: Hameroff published Ultimate Computing, the response from mainstream neuroscience ranged
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Speaker 1: from polite skepticism to open dismissal. The brain was too warm,
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Speaker 1: critics said. Quantum coherence requires isolation from thermal noise and
20:42
Speaker 1: a neuron at 37 degrees Celsius surrounded by water molecules
20:47
Speaker 1: colliding at thermal rates of 10 trillion times per second
20:52
Speaker 1: was the opposite of isolated. Those collisions, each one a
20:56
Speaker 1: tiny interaction with the environment, would collapse any superposition almost instantly.
21:04
Speaker 1: The decoherence time The time before the quantum information was
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Speaker 1: washed out by the thermal bath was calculated to be
21:13
Speaker 1: somewhere around a ten-thousandth of a billionth of a second.
21:18
Speaker 1: That is ten to the power of negative thirteen seconds.
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Speaker 1: The brain's neurons fire at roughly forty times per second,
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Speaker 1: which means any quantum process would need to survive for
21:31
Speaker 1: at least twenty-five thousandths of a second to do anything useful.
21:37
Speaker 1: The gap between 10 to the minus 13 seconds and
21:40
Speaker 1: 25 thousandths of a second is 13 orders of magnitude,
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Speaker 1: 13 powers of 10. The dismissal, for many physicists, felt airtight.
21:52
Speaker 1: But here is the part that the dismissal did not
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Speaker 1: account for. In 2022, a team led by Craddock and
22:02
Speaker 1: Kurian and published in Communications Biology did something the critics
22:08
Speaker 1: had not done. They looked inside the tubulin dimer at
22:12
Speaker 1: the specific molecules responsible for its optical and electronic properties,
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Speaker 1: and what they found was a network of tryptophan residues
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Speaker 1: arranged in a lattice with a geometry that was not random.
22:28
Speaker 1: Tryptophan is an aromatic amino acid, meaning it contains a
22:33
Speaker 1: ring of carbon atoms with electrons that can move freely
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Speaker 1: across the ring, a structure physicists call a conjugated pi system.
22:43
Speaker 1: In the tubulin lattice, these tryptophan residues are spaced at
22:47
Speaker 1: intervals of roughly 1.2 nanometers, and at that spacing they
22:53
Speaker 1: are within what is called the Forster energy transfer distance.
22:57
Speaker 1: The range over which quantum resonance energy transfer between molecules
23:03
Speaker 1: is not just possible but efficient. The spectroscopic measurements showed
23:08
Speaker 1: quantum coherent oscillations within this tryptophan network at room temperature
23:14
Speaker 1: with coherence times in the range of hundreds of femtoseconds.
23:19
Speaker 1: A femtosecond is a millionth of a billionth of a second,
23:23
Speaker 1: so hundreds of femtoseconds is still very short. but it
23:27
Speaker 1: is the same time scale measured in photosynthetic systems that
23:32
Speaker 1: had already demolished the assumption that warm biology must be classical.
23:39
Speaker 1: The paper went further. The geometry of the tryptophan lattice
23:44
Speaker 1: inside tubulin was shown computationally to match the topology of
23:50
Speaker 1: a quantum error correcting code, specifically a surface code. which
23:57
Speaker 1: is one of the most promising architectures in engineered quantum
24:01
Speaker 1: computing for protecting information against decoherence. The lattice was not
24:07
Speaker 1: just coherent. It appeared to be structured in a way
24:11
Speaker 1: that resists decoherence by encoding information in global topological features
24:18
Speaker 1: rather than in any single vulnerable local site. And then
24:23
Speaker 1: the drug experiment, Taxol, is a chemotherapy agent derived from
24:29
Speaker 1: the bark of the Pacific yew tree, and its mechanism
24:33
Speaker 1: of action in cancer treatment is that it binds to
24:36
Speaker 1: the interior of microtubules and prevents their normal dynamic behavior,
24:42
Speaker 1: locking them in the polymerized state. In a 2023 paper
24:49
Speaker 1: in Neuroscience of Consciousness, Craddock and Hameroff and colleagues gave
24:54
Speaker 1: Taxol to Ratz and then administered isoflurane anesthetic and measured
25:00
Speaker 1: how long it took for the rats to lose their
25:03
Speaker 1: writing reflex, which is the standard proxy for loss of
25:07
Speaker 1: consciousness in rodent studies. The Taxol-treated rats took 23% longer
25:15
Speaker 1: to go under, not a small effect, a statistically significant
25:21
Speaker 1: dose-dependent effect in the direction that microtubule stabilization prolongs the
25:28
Speaker 1: quantum coherent state and makes consciousness harder to extinguish. The
25:33
Speaker 1: scaffolding hypothesis is dead and buried because the numbers no
25:38
Speaker 1: longer support it, and what replaces it is the possibility
25:43
Speaker 1: that every neuron in your brain is running a quantum
25:47
Speaker 1: process on a protein crystal the size of a virus.
25:52
Speaker 1: A crystal that has spent a billion years of evolution
25:56
Speaker 1: learning to protect its quantum information from the thermal storm
26:01
Speaker 1: surrounding it. But a protein crystal inside a warm, wet
26:05
Speaker 1: cell is not supposed to maintain quantum coherence for more
26:11
Speaker 1: than femtoseconds, and the brain would not be the first
26:15
Speaker 1: place to raise that objection. The answer came not from
26:20
Speaker 1: a brain lab but from a garden, from the moment
26:23
Speaker 1: in 2007 when a laser pulse hit a leaf and
26:27
Speaker 1: the result made physicists stop talking. The green sulfur bacterium
26:33
Speaker 1: is not a plant. It is older than plants by
26:36
Speaker 1: more than a billion years, and it lives in places
26:40
Speaker 1: where sunlight barely reaches, at the bottom of lakes and
26:45
Speaker 1: in the thin illuminated margins of deep-sea hydrothermal vents. it
26:52
Speaker 1: cannot afford to waste a single photon. In 2007, a
26:58
Speaker 1: team at the University of California at Berkeley fired pulses
27:03
Speaker 1: of laser light at samples of this organism, each pulse
27:07
Speaker 1: lasting fewer than 50 femtoseconds, which is 50 millionths of
27:13
Speaker 1: a billionth of a second, and they watched what happened
27:17
Speaker 1: to the energy that entered the bacterium's light-harvesting antenna complex.
27:23
Speaker 1: What they saw should not have been possible under any
27:27
Speaker 1: classical description of chemistry. The energy moved through the antenna
27:33
Speaker 1: complex and arrived at the reaction center, the site where
27:38
Speaker 1: it would be converted into chemical work, with an efficiency
27:42
Speaker 1: approaching 100%, not 80%. not ninety. Nearly every quantum of
27:52
Speaker 1: energy that entered the system arrived at its destination without
27:58
Speaker 1: being scattered, lost to heat, or wasted in the kind
28:02
Speaker 1: of random diffusion that governs every classical energy transfer process
28:08
Speaker 1: biology was assumed to use. Classical random walk physics is
28:15
Speaker 1: The model that describes how energy hops from molecule to
28:19
Speaker 1: molecule through thermal collisions predicts an efficiency in the range
28:25
Speaker 1: of 70 to 80 percent at best. And the gap
28:29
Speaker 1: between that prediction and the measured result was not a
28:33
Speaker 1: rounding error. It was a fundamental discrepancy, and it pointed
28:38
Speaker 1: in only one direction. The antenna complex was not searching
28:43
Speaker 1: randomly for the reaction center. It was finding it the
28:46
Speaker 1: way a quantum system finds a solution, by exploring all
28:51
Speaker 1: possible paths simultaneously and arriving at the answer through interference,
28:57
Speaker 1: amplifying the routes that lead to the destination and cancelling
29:01
Speaker 1: the routes that do not. That process has a name
29:05
Speaker 1: in physics. It is quantum coherence, and in 2007 it
29:11
Speaker 1: had no business existing inside a living cell at any
29:14
Speaker 1: temperature above a few degrees above absolute zero. Graham Fleming
29:21
Speaker 1: had spent his career building the instruments that made this
29:24
Speaker 1: measurement possible. He is a physical chemist, and the laser
29:29
Speaker 1: systems he constructed at Berkeley were designed to probe molecular
29:34
Speaker 1: dynamics on time scales that had previously been inaccessible to
29:39
Speaker 1: any experiment. Femtosecond spectroscopy, the technique his group used, works
29:46
Speaker 1: by firing a pump pulse into a sample to excite
29:49
Speaker 1: it and then probing it with a second pulse at
29:53
Speaker 1: precisely controlled time delays, capturing snapshots of molecular motion faster
30:00
Speaker 1: than any chemical bond can vibrate. Fleming had used these
30:05
Speaker 1: tools to study photosynthesis for years, but he had been
30:10
Speaker 1: looking for classical dynamics. What appeared in the data instead
30:15
Speaker 1: was a beating signal, an oscillation in the quantum state
30:19
Speaker 1: of the bacterium's antenna complex that persisted across hundreds of femtoseconds.
30:27
Speaker 1: and that had the unmistakable mathematical signature of quantum coherence.
30:33
Speaker 1: Fleming later described that moment as the point at which
30:37
Speaker 1: he understood that biology had been running a quantum algorithm
30:42
Speaker 1: for three billion years without anyone in physics noticing. The
30:48
Speaker 1: paper was published in Nature in 2007 under the title
30:54
Speaker 1: Evidence for Wavelike Energy Transfer through quantum coherence in photosynthetic systems.
31:02
Speaker 1: And it named the structure responsible, the Phenomathus-Olson complex, a
31:08
Speaker 1: protein assembly first characterized crystallographically in the 1970s that connects
31:15
Speaker 1: the bacterium's outer antenna array to its reaction center. The
31:21
Speaker 1: quantum coherence in that complex persisted for 660 femtoseconds at
31:28
Speaker 1: 77 Kelvin, which is extremely cold, about the temperature of
31:33
Speaker 1: liquid nitrogen. Cold enough, the skeptics said, to be unsurprising.
31:40
Speaker 1: Cold enough, perhaps, to be a laboratory artifact with no
31:45
Speaker 1: relevance to a warm living cell. But that is not
31:50
Speaker 1: the strange part. In 2010, a paper by Elisabetta Collini
31:56
Speaker 1: and colleagues appeared in nature reporting quantum coherence in a
32:01
Speaker 1: marine cryptophyte, ALGA, measured at 294 Kelvin. That is essentially
32:08
Speaker 1: room temperature, 21 degrees Celsius, the temperature of a summer afternoon,
32:15
Speaker 1: the temperature of a living cell conducting its normal business.
32:19
Speaker 1: The coherence persisted for over 400 femtoseconds at that temperature.
32:26
Speaker 1: and the organism was alive and functioning while it did so.
32:31
Speaker 1: The cold artifact objection was gone. What followed in the
32:36
Speaker 1: next several years was a systematic investigation of the mechanism,
32:42
Speaker 1: and the mechanism turned out to be the stranger result
32:45
Speaker 1: by far. The question physicists asked was why the protein
32:50
Speaker 1: environments surrounding the pigment molecules was not destroying the quantum coherence.
32:57
Speaker 1: In any naive picture of quantum mechanics, the environment is
33:01
Speaker 1: the enemy. Every thermal fluctuation, every vibration, every collision with
33:08
Speaker 1: a water molecule is a measurement event that collapses quantum
33:12
Speaker 1: superposition and returns the system to classical behavior. The protein
33:17
Speaker 1: scaffold around the Fenna-Matthews-Olson complex is warm and vibrating constantly.
33:25
Speaker 1: It should be demolishing the coherence at every moment. Instead,
33:30
Speaker 1: the data showed it was sustaining it. The explanation is
33:35
Speaker 1: called vibronic coupling, sometimes described under the broader framework of
33:42
Speaker 1: environment-assisted quantum transport, which researchers in the field abbreviate as ENACT.
33:51
Speaker 1: The protein scaffold is not quiet. It vibrates and its
33:56
Speaker 1: vibrational modes, the phonons of the protein lattice, have frequencies
34:01
Speaker 1: that are tuned by evolution to match the energy gaps
34:05
Speaker 1: between the electronic states of the pigment molecules embedded within it.
34:11
Speaker 1: When the electronic transition energy of a pigment, the gap
34:15
Speaker 1: between its ground state and its excited state, matches the
34:19
Speaker 1: vibrational frequency of the surrounding protein, the two systems couple.
34:25
Speaker 1: The noise of the protein lattice does not scatter the
34:29
Speaker 1: quantum state randomly. It reinforces it. The scaffold is not
34:36
Speaker 1: a wall that coherence has to fight through. It is
34:39
Speaker 1: a resonator that coherence is playing in. This reframing changed everything.
34:47
Speaker 1: The assumption that that had dominated quantum biology skepticism for
34:52
Speaker 1: decades was that the warm, wet interior of a cell
34:56
Speaker 1: is necessarily hostile to quantum coherence, that any quantum effect
35:02
Speaker 1: would be drowned immediately in thermal noise. The photosynthetic result
35:09
Speaker 1: showed that this assumption was not a law of physics,
35:13
Speaker 1: but a failure of biological imagination. evolution had three billion
35:18
Speaker 1: years to find protein geometries that turned thermal noise from
35:22
Speaker 1: a source of decoherence into a resource for sustaining it.
35:27
Speaker 1: And in at least six different photosynthetic organisms, as documented
35:32
Speaker 1: in a 2014 review in Nature Chemistry by Fleming and
35:37
Speaker 1: Gregory Scholes, evolution appears to have found exactly that solution independently,
35:44
Speaker 1: multiple times. on multiple branches of the tree of life.
35:49
Speaker 1: The efficiency advantage of quantum coherence over classical random walk
35:55
Speaker 1: in these systems is estimated at somewhere between 10 and
35:59
Speaker 1: 30 percent, depending on the organism and the conditions. That
36:04
Speaker 1: number sounds modest, but in evolutionary terms it is enormous.
36:10
Speaker 1: An organism that captures 10% more energy from every photon
36:15
Speaker 1: it absorbs in a light-limited environment has an overwhelming selective
36:21
Speaker 1: advantage over geological time. The quantum algorithm is not a
36:27
Speaker 1: curiosity tucked into a corner of photosynthetic biochemistry. It is
36:33
Speaker 1: the engine the organism runs on. And the moment you
36:38
Speaker 1: understand that, The question that follows is not whether quantum
36:42
Speaker 1: coherence in biology is real. That question is settled by
36:47
Speaker 1: the data. The question that follows is whether the warm,
36:51
Speaker 1: wet solution that photosynthesis found, the protein scaffold tuned to
36:56
Speaker 1: use its own vibrations as a coherence resource, is unique
37:01
Speaker 1: to light harvesting, or whether evolution discovered it in other
37:06
Speaker 1: contexts as well. Whether a neuron... surrounded by its own
37:11
Speaker 1: protein environment threaded with microtubule lattices whose crystalline geometry has
37:18
Speaker 1: also been shaped by a billion years of selection pressure,
37:23
Speaker 1: might be doing something structurally similar to what the green
37:28
Speaker 1: sulfur bacterium does every time a photon finds its way
37:33
Speaker 1: through the dark water to its antennae. Biology already solved
37:38
Speaker 1: the decoherence problem three billion years ago, and it solved
37:42
Speaker 1: it not by cooling down, but by tuning the noise,
37:46
Speaker 1: which means the warm, wet objection to quantum biology in
37:50
Speaker 1: the brain has lost the strongest argument it ever had.
37:55
Speaker 1: The question is no longer whether warm biology can sustain
37:59
Speaker 1: quantum coherence. The question is which warm biological systems chose to.
38:06
Speaker 1: and if the brain's protein environment might be doing something similar,
38:11
Speaker 1: then the next place to look is not in a
38:14
Speaker 1: neuron's interior, but in the most sensitive quantum biological detector
38:19
Speaker 1: ever discovered in a living animal, the eye of a
38:23
Speaker 1: bird that crosses an entire continent guided by the spin
38:27
Speaker 1: state of a single electron, a compass with no moving
38:32
Speaker 1: parts and no classical explanations. NAVIGATING BY ENTANGLEMENT A European
38:39
Speaker 1: robin weighs 18 grams. Hold a small mandarin orange in
38:44
Speaker 1: your hand, and you are holding roughly its weight. That bird,
38:49
Speaker 1: in autumn, lifts off from a Scandinavian forest and flies
38:53
Speaker 1: south and west across the North Sea, across France, across
38:58
Speaker 1: the Mediterranean, and into sub-Saharan Africa and arriving at a
39:03
Speaker 1: destination it has never visited, guided by a compass that
39:06
Speaker 1: contains no iron, no crystal, no moving part of any kind,
39:12
Speaker 1: and no mechanism that classical physics can account for. What
39:16
Speaker 1: it contains instead is a single protein in the retina,
39:21
Speaker 1: and inside that protein, two electrons whose quantum spin states
39:26
Speaker 1: become entangled the instant a photon of blue morning light
39:31
Speaker 1: strikes a molecule no bigger than a vitamin. The compass
39:37
Speaker 1: is not a metaphor. It is doing something that, until
39:40
Speaker 1: very recently, physicists insisted warm living tissue simply could not do.
39:48
Speaker 1: Henrik Moritzson did not begin his career looking for quantum mechanics.
39:54
Speaker 1: He is a biologist at the University of Oldenburg in Germany,
39:59
Speaker 1: and what he wanted to understand in the late 1990s
40:03
Speaker 1: was the straightforward behavioral question of how migratory birds know
40:09
Speaker 1: which direction to fly. The answer everyone expected involved magnetite,
40:16
Speaker 1: tiny crystals of iron oxide that some animals carry in
40:20
Speaker 1: their beaks and inner ears, and that could, in principle,
40:24
Speaker 1: act as a classical magnetic compass needle. Moritzson tested Robbins
40:30
Speaker 1: for magnetite-based navigation. The evidence was unconvincing. Then he tried
40:37
Speaker 1: something stranger. He built a series of wooden huts on
40:41
Speaker 1: the grounds of the university. constructed specifically to exclude electromagnetic fields.
40:49
Speaker 1: The walls were lined with aluminum to screen out urban
40:52
Speaker 1: radio noise. The huts had no metal fixtures, no electrical
40:57
Speaker 1: wiring inside the test area, no sources of artificial electromagnetic
41:04
Speaker 1: radiation of any kind. He placed Robbins inside orientation cages
41:10
Speaker 1: in these huts during the migratory season. when the birds
41:14
Speaker 1: are restless and oriented, and he compared their directional choices
41:19
Speaker 1: with robins in ordinary outdoor cages exposed to the normal
41:25
Speaker 1: electromagnetic environment of a small German city. The robins in
41:31
Speaker 1: the shielded huts oriented perfectly. They pointed toward their migratory
41:36
Speaker 1: direction as cleanly as compass needles. The robins in the
41:42
Speaker 1: unshielded outdoor cages were disoriented. They pointed in random directions,
41:49
Speaker 1: unable to find north. The difference between those two environments
41:55
Speaker 1: was not the strength of the magnetic field. Earth's magnetic
42:00
Speaker 1: field penetrated both settings equally. The difference was the presence
42:05
Speaker 1: or absence of weak, oscillating, urban radio frequency electromagnetic noise,
42:13
Speaker 1: fields so faint that they carry no energy significant enough
42:18
Speaker 1: to affect any known classical biological sensor. And yet, they
42:24
Speaker 1: were enough to destroy the magnetic compass of a migratory bird.
42:30
Speaker 1: That finding, published in Nature in 2004, and extended in
42:36
Speaker 1: a follow-up paper in 2014, is where the quantum explanation
42:41
Speaker 1: becomes unavoidable rather than merely interesting. Moritzson and his colleagues
42:47
Speaker 1: showed that the disorienting effect was sharpest at a very
42:52
Speaker 1: specific frequency, 1.4 MHz. That number is not arbitrary. It
43:00
Speaker 1: is the Larmor frequency, the resonant frequency at which quantum
43:05
Speaker 1: spin states precess in Earth's magnetic field. A classical compass
43:11
Speaker 1: made of magnetite crystals would be completely insensitive to an
43:16
Speaker 1: oscillating field at that frequency. But a quantum system based
43:22
Speaker 1: on electron spin states would be exquisitely sensitive to exactly
43:27
Speaker 1: that disruption, because 1.4 MHz is the frequency at which
43:33
Speaker 1: a weak oscillating field can flip the spin states and
43:38
Speaker 1: scramble the singlet to triplet ratio that the compass reads
43:42
Speaker 1: as directional information. The idea that the compass was quantum
43:47
Speaker 1: mechanical in origin had been proposed decades earlier. Klaus Schulten,
43:53
Speaker 1: a biophysicist then at the University of Illinois, put forward
43:58
Speaker 1: the radical pair mechanism in 1978 and spent the following
44:03
Speaker 1: two decades watching the scientific community politely ignore it. His
44:10
Speaker 1: proposal was that a class of proteins called cryptochromes, found
44:15
Speaker 1: in the eyes of birds, could generate pairs of electrons
44:19
Speaker 1: whose quantum spin states depended on the orientation of the
44:24
Speaker 1: surrounding magnetic field. The bird could, in principle, read that
44:29
Speaker 1: spin information as a compass bearing. The idea was elegant,
44:34
Speaker 1: it was mathematically coherent, and for twenty years almost nobody
44:39
Speaker 1: believed it could be happening in a warm animal. What
44:43
Speaker 1: changed the conversation was the experimental evidence from Moritzson's huts,
44:49
Speaker 1: and then the biochemistry that followed. Cryptochrome proteins in the
44:56
Speaker 1: robin's retina contain a molecule called flavinadenin denucleotide, which researchers
45:02
Speaker 1: abbreviate to FAD. When a photon of blue light strikes
45:06
Speaker 1: FAD inside the cryptochrome, it kicks an electron across to
45:11
Speaker 1: a nearby tryptophan residue. The result is a radical pair,
45:16
Speaker 1: two molecules, each carrying one unpaired electron, physically separated but
45:22
Speaker 1: quantum mechanically linked. Those two electrons do not each have
45:26
Speaker 1: a definite spin. They exist together in a superposition of
45:31
Speaker 1: spin states, specifically a mixture of what physicists call the
45:37
Speaker 1: singlet state, in which the spins are anti-parallel and paired,
45:42
Speaker 1: and the triplet state, in which the spins are parallel
45:45
Speaker 1: and unpaired. Earth's magnetic field, at roughly 50 microtesla, is
45:52
Speaker 1: genuinely tiny. It is too weak by many orders of
45:56
Speaker 1: magnitude to to pull on a chemical bond or rotate
46:00
Speaker 1: a magnetite crystal in a way that would produce directional
46:04
Speaker 1: information in classical chemistry. But 50 microtesla is precisely the
46:11
Speaker 1: right scale to gently shift the balance between singlet and
46:16
Speaker 1: triplet states in a radical pair over the lifetime of
46:20
Speaker 1: the pair. Different orientations of the bird's head relative to
46:24
Speaker 1: the magnetic field lines produce different singlet to triplet ratios.
46:31
Speaker 1: The cryptochrome protein converts those ratios into a downstream chemical signal.
46:38
Speaker 1: The bird experiences this as a visual or field sensation,
46:44
Speaker 1: a sense of magnetic direction that appears to overlay its
46:48
Speaker 1: normal vision, possibly as a gradient of light or shadow
46:53
Speaker 1: that across the visual field depending on which way the
46:57
Speaker 1: bird faces. The entanglement in the radical pair, the quantum
47:03
Speaker 1: coupling between the two separated electrons, survives for at least
47:08
Speaker 1: one microsecond inside the protein environment at body temperature. One
47:14
Speaker 1: microsecond sounds brief. But compared to what physicists initially calculated
47:21
Speaker 1: for quantum coherence in warm biological matter, it is roughly
47:26
Speaker 1: a million times longer than it should be. The protein
47:31
Speaker 1: scaffold around the radical pair is not simply failing to
47:36
Speaker 1: disrupt the entanglement. It is actively preserving it in a
47:41
Speaker 1: manner that echoes what the previous chapter described in photosynthetic
47:45
Speaker 1: proteins where vibrational frequencies of the scaffold were tuned to
47:51
Speaker 1: sustain rather than destroy quantum effects. The direct biochemical confirmation
47:58
Speaker 1: arrived in a 2021 paper in Nature by Xu and colleagues,
48:05
Speaker 1: working between Frankfurt and Oldenburg. They expressed cryptochrome 4A, the
48:11
Speaker 1: specific variant from the European robin's retina, and measured its
48:16
Speaker 1: radical pair properties directly. The magnetic sensitivity of the protein
48:22
Speaker 1: matched what the behavioral disorientation experiments required. The radical pair
48:29
Speaker 1: in Robin Cryptochrome 4A is not marginally quantum mechanical or
48:35
Speaker 1: borderline sensitive. It is precisely tuned to the relevant scale
48:41
Speaker 1: of Earth's magnetic field, with sensitivity that modern quantum sensing
48:46
Speaker 1: laboratories have only recently matched using engineered devices built specifically
48:52
Speaker 1: for that purpose. A bird's eye protein, shaped by evolution,
48:58
Speaker 1: performs at the level of a precision physics instrument. Moritzson
49:03
Speaker 1: has spoken about the strangeness of where this evidence leads.
49:07
Speaker 1: A biologist studying bird migration says, ends up standing in
49:12
Speaker 1: a wooden hut in northern Germany, having eliminated every classical
49:17
Speaker 1: explanation one by one. holding a result that requires quantum
49:22
Speaker 1: entanglement as a necessary component of animal behavior not as
49:28
Speaker 1: a marginal correction to an otherwise classical story but as
49:32
Speaker 1: the central mechanism without which the bird cannot find its
49:36
Speaker 1: way QUANTUM ENTANGLEMENT IS NOT THEN A PHENOMENON THAT EXISTS
49:41
Speaker 1: ONLY AT MILLIKELVIN TEMPERATURES INSIDE SUPERCONDUCTING CHIPS IN PHYSICS LABORATORIES.
49:47
Speaker 1: IT EXISTS RIGHT NOW, THIS NIGHT, IN THE EYES OF
49:51
Speaker 1: BIRDS FLYING SOUTH OVER A DARK SEA. IT GUIDES THEM,
49:56
Speaker 1: IT HAS GUIDED THEM FOR MILLIONS OF YEARS, AND THE
49:59
Speaker 1: PROTEIN THAT ACHIEVES IT IS DOING SO AT BODY TEMPERATURE,
50:04
Speaker 1: IN A WARM, WET CELLULAR ENVIRONMENT. SUSTAINED BY A MOLECULAR
50:08
Speaker 1: GEOMETRY THAT EVOLUTION SELECTED BECAUSE QUANTUM COHERENCE WAS TOO USEFUL
50:15
Speaker 1: TO ABANDON. THAT IS THE POINT AT WHICH THE WARM,
50:20
Speaker 1: WET OBJECTION TO QUANTUM BIOLOGY IN THE BRAIN CHANGES CHARACTER.
50:26
Speaker 1: IT WAS ONCE A STATEMENT ABOUT PHYSICS. IT IS NOW
50:30
Speaker 1: A STATEMENT ABOUT WHICH WARM, WET SYSTEMS BIOLOGY CHOSE TO EXPLOIT.
50:36
Speaker 1: The Robbins compass works because a single protein is geometrically
50:41
Speaker 1: tuned to preserve quantum spin states long enough to carry information.
50:47
Speaker 1: And if you want to know whether the brain has
50:49
Speaker 1: a protein geometry capable of something structurally similar, the next
50:54
Speaker 1: experiment was not done with a bird, but with a
50:58
Speaker 1: very precise nuclear magnetic resonance instrument, and a sample of
51:03
Speaker 1: powdered tubulin protein extracted from brain tissue, and the result
51:08
Speaker 1: it produced came through in data that made the lead
51:12
Speaker 1: researcher reach for a phone at two in the morning.
51:18
Speaker 1: The call was made to John Joe McFadden, a molecular
51:22
Speaker 1: biologist at the University of Surrey who had spent the
51:26
Speaker 1: better part of two decades investigating telling anyone willing to
51:30
Speaker 1: listen that quantum effects inside living cells were not the exception,
51:36
Speaker 1: but a deeply underappreciated rule. McFadden had co-written a book
51:42
Speaker 1: in 2015 called Life on the Edge, which laid out
51:47
Speaker 1: the case for quantum biology with the patience of someone
51:51
Speaker 1: who knew he was arguing against the grain and had
51:54
Speaker 1: chosen to do it anyway. The mainstream view, held firmly
51:59
Speaker 1: by most neuroscientists and a great many physicists, was that
52:04
Speaker 1: quantum coherence in brain tissue was a romantic idea without
52:09
Speaker 1: experimental grounding. The phone call that morning was about experimental grounding.
52:16
Speaker 1: The measurement came from a tubulin sample, the same protein
52:20
Speaker 1: that builds those seven nanometer hollow tubes inside every neuron.
52:26
Speaker 1: the same structure that Stuart Hameroff had been studying since
52:30
Speaker 1: the 1980s and that most cell biologists still preferred to
52:36
Speaker 1: describe as structural scaffolding. A team including Craddock, Kurian, Prato
52:44
Speaker 1: and Sahu had placed the tubulin in a two-dimensional electronic
52:49
Speaker 1: spectroscopy instrument. a technique that fires precisely timed femtosecond laser
52:56
Speaker 1: pulses at a sample and reads the quantum oscillations that
53:01
Speaker 1: result in the way the sample absorbs and re-emits that light.
53:06
Speaker 1: The technique had been the same one used in the
53:09
Speaker 1: photosynthesis experiments a decade earlier. The one that revealed quantum
53:15
Speaker 1: coherence in the green sulfur bacterium's antenna complex Now it
53:20
Speaker 1: was aimed at brain protein. And at 310 Kelvin, which
53:25
Speaker 1: is normal human body temperature, the data showed quantum coherent
53:30
Speaker 1: oscillations in the tryptophan networks threaded through the tubulin structure.
53:36
Speaker 1: The oscillation was there. It was not noise. It was
53:40
Speaker 1: not an artifact of the instrument. It was a quantum
53:44
Speaker 1: coherence signal persisting at biological temperature in a protein taken
53:50
Speaker 1: from brain tissue. Tryptophan is an amino acid, one of
53:56
Speaker 1: the building blocks of proteins, but it has a property
54:00
Speaker 1: that most amino acids lack. Its molecular structure contains a
54:05
Speaker 1: ring of atoms with electrons that are not anchored to
54:09
Speaker 1: any single bond, but are spread across the whole ring
54:13
Speaker 1: in what chemists call a conjugated pi electron system. Those
54:19
Speaker 1: delocalized electrons are the same class of quantum mechanical resource
54:24
Speaker 1: that photosynthetic pigments exploit. In the tubulin protein, the tryptophan
54:30
Speaker 1: residues are not scattered randomly. They are arranged in a lattice,
54:35
Speaker 1: spaced at intervals of roughly 1.2 nanometers. That spacing is
54:42
Speaker 1: significant because it falls near what physicists call the Forster
54:47
Speaker 1: energy transfer distance, the range over which quantum resonance between
54:52
Speaker 1: identical molecular systems is efficient. Put two quantum resonators at
54:58
Speaker 1: the right distance from each other, and energy does not
55:01
Speaker 1: hop between them by random diffusion. It spreads through both
55:06
Speaker 1: at once, as a quantum superposition, sampling all paths simultaneously
55:12
Speaker 1: before resolving. That is the mechanism that makes photosynthesis so efficient.
55:20
Speaker 1: And in tubulin, the geometry was set up to do
55:23
Speaker 1: the same thing. The coherence times measured in that 2022 paper,
55:30
Speaker 1: published in Communications Biology, ran into the range of hundreds
55:35
Speaker 1: of femtoseconds. A femtosecond is one millionth of a billionth
55:41
Speaker 1: of a second, which sounds impossibly brief until you remember
55:46
Speaker 1: that the photosynthetic systems in green sulfur bacteria showed coherence
55:52
Speaker 1: at comparable timescales, and those timescales turned out to be
55:57
Speaker 1: long enough for quantum energy routing to work with near-perfect efficiency.
56:03
Speaker 1: The relevant question is never how long the coherence lasts
56:08
Speaker 1: in absolute terms. The relevant question is whether it lasts
56:13
Speaker 1: long enough to do something useful before thermal noise collapses it.
56:19
Speaker 1: In the bacterium, hundreds of femtoseconds was enough. Whether hundreds
56:24
Speaker 1: of femtoseconds in tubulin is enough for whatever the brain
56:29
Speaker 1: might be doing with it is a question the measurement
56:32
Speaker 1: alone cannot answer. But the measurement establishes that the coherence
56:37
Speaker 1: is real. Critics had one objection left, and it was
56:42
Speaker 1: a good one. Even if tryptophan networks in tubulin showed
56:48
Speaker 1: quantum coherence, what was stopping thermal collisions in the surrounding
56:54
Speaker 1: cellular water from destroying it almost immediately? The protein exists
57:00
Speaker 1: inside a neuron at body temperature, surrounded by water molecules
57:05
Speaker 1: vibrating energetically, at a rate of roughly 10 trillion collisions
57:11
Speaker 1: per second. Each collision is, in quantum mechanical terms, a
57:17
Speaker 1: measurement of the protein's quantum state, and measurements collapse superpositions.
57:23
Speaker 1: The Tegmark decoherence calculation from the year 2000 had put
57:28
Speaker 1: the survival time of any quantum superposition in a biological
57:33
Speaker 1: neuron at around 1 ten trillionth of a second. Hundreds
57:39
Speaker 1: of femtoseconds is actually longer than that. Something in the
57:43
Speaker 1: tubulin environment was protecting the coherence against the expected rate
57:48
Speaker 1: of collapse. The answer appears to lie in the geometry
57:53
Speaker 1: of the tryptophan lattice itself. A research team working on
57:57
Speaker 1: the computational side of the problem showed that the arrangement
58:02
Speaker 1: of tryptophan residues in the tubulin structure matches with striking
58:07
Speaker 1: precision the topology of a quantum error correcting code. Quantum
58:13
Speaker 1: error correction is a strategy developed in quantum computing research
58:19
Speaker 1: to protect fragile quantum information from environmental disturbance. Instead of
58:26
Speaker 1: storing information in a single quantum system that can be
58:30
Speaker 1: disrupted by a single thermal collision, you encode it in
58:35
Speaker 1: the global pattern of a large network of entangled systems,
58:40
Speaker 1: so that no single local disturbance can read out or
58:45
Speaker 1: destroy the information without affecting the entire network simultaneously. The
58:52
Speaker 1: information is not in any one tryptophan molecule. It is
58:57
Speaker 1: in the relationship between all of them at once. A
59:01
Speaker 1: water molecule bumping into one tryptophan does not collapse the
59:05
Speaker 1: global quantum state. because that state is not localized to
59:10
Speaker 1: any single molecule that can be measured by a single
59:14
Speaker 1: collision This is not a new principle invented to protect
59:18
Speaker 1: a favored theory Topological quantum error correction is one of
59:23
Speaker 1: the most active areas in quantum computing engineering precisely because
59:28
Speaker 1: it works so well Major technology laboratories are spending considerable
59:34
Speaker 1: resources trying to build artificial structures that implement it. The
59:41
Speaker 1: claim that tubulin implements something equivalent naturally is large, but
59:47
Speaker 1: the geometric match between the tryptophan lattice and the required
59:51
Speaker 1: topology was shown computationally, not asserted, and the coherence time
59:57
Speaker 1: seen in the spectroscopy data fit what you would expect
1:00:01
Speaker 1: if that protection were real. Earlier experimental evidence had been
1:00:07
Speaker 1: pointing in the same direction for years. In 2013, Sahu
1:00:13
Speaker 1: and colleagues published work in scientific reports showing that single
1:00:19
Speaker 1: isolated microtubules pulled from cells and measured individually conduct electrical
1:00:27
Speaker 1: oscillations at multiple resonant frequencies simultaneously. Classical electrical cable theory,
1:00:35
Speaker 1: the framework that describes how neurons carry signals, predicts a
1:00:40
Speaker 1: single characteristic frequency for any given cable geometry. Multiple simultaneous
1:00:48
Speaker 1: resonances are not a classical prediction. They are what you
1:00:54
Speaker 1: would expect from a system supporting quantum superposition. Then in 2019,
1:01:02
Speaker 1: Bandiopadier and colleagues published measurements in APE Advances showing that
1:01:07
Speaker 1: microtubule electrical conductance carries quantum interference patterns, the alternating constructive
1:01:15
Speaker 1: and destructive reinforcement of wave functions that is one of
1:01:20
Speaker 1: the most direct observable signatures of quantum mechanical behavior. An
1:01:26
Speaker 1: electron passing through a microtubule was interfering with itself, which
1:01:32
Speaker 1: means it was traveling as a wave through multiple paths
1:01:35
Speaker 1: at once before resolving into a single measured outcome. For McFadden,
1:01:42
Speaker 1: the convergence of these independent lines of evidence was the
1:01:46
Speaker 1: pivot point. Spectroscopy from Surrey Conductance measurements from Japan crystallographic
1:01:56
Speaker 1: order established by electron microscopy, quantum chemistry calculations matching the
1:02:03
Speaker 1: lattice geometry to error-correcting codes. Each experiment used a different instrument,
1:02:12
Speaker 1: a different technique, a different physical observable. None of them
1:02:17
Speaker 1: were designed to confirm the others. And all of them
1:02:21
Speaker 1: pointed at the same place inside the tubulin protein, to
1:02:26
Speaker 1: the tryptophan lattice, to quantum coherent oscillations persisting at body
1:02:31
Speaker 1: temperature in the building block of every microtubule in every
1:02:36
Speaker 1: neuron you will ever have. McFadden described the shift in
1:02:41
Speaker 1: the field's character not as a moment of triumph, but
1:02:45
Speaker 1: as a settling. The way a debate changes texture when
1:02:50
Speaker 1: one side stops being able to dismiss the data and
1:02:54
Speaker 1: starts having to explain it. Quantum coherence in brain proteins
1:02:59
Speaker 1: is no longer a prediction written in the margins of
1:03:03
Speaker 1: a speculative book. It is a measurement, replicated across methods,
1:03:09
Speaker 1: pointing in one direction. And measurements are what science runs on.
1:03:15
Speaker 1: But a measurement that something is happening does not tell
1:03:18
Speaker 1: you what that something is for. The question of why
1:03:22
Speaker 1: a brain protein would run a quantum coherence process, what
1:03:26
Speaker 1: that process computes, what it means for the experience of
1:03:30
Speaker 1: being awake inside a skull, is a different question entirely,
1:03:36
Speaker 1: and the most radical answer to it was not written
1:03:39
Speaker 1: in a laboratory. It was written at a desk in
1:03:42
Speaker 1: Oxford in 1989 by a mathematician who began not with
1:03:48
Speaker 1: proteins or photons, but with a theorem about the permanent
1:03:52
Speaker 1: limits of what any computer can ever prove, and whose
1:03:56
Speaker 1: conclusion was that something you can do on a Tuesday morning,
1:04:01
Speaker 1: a computer running any program ever written, cannot do at all.
1:04:06
Speaker 1: Roger Penrose published The Emperor's New Mind in 1989, and
1:04:11
Speaker 1: the argument at its center was not about neurons or
1:04:14
Speaker 1: proteins or quantum mechanics. It was about a theorem about
1:04:19
Speaker 1: proved by a 25-year-old Austrian mathematician in 1931, a theorem
1:04:26
Speaker 1: so strange and so precise that even its author, Kurt Gödel,
1:04:31
Speaker 1: seemed unsettled by what he had found. Gödel' s first incompleteness
1:04:37
Speaker 1: theorem states that any formal system powerful enough to describe
1:04:42
Speaker 1: ordinary arithmetic contains true statements that cannot be proved within
1:04:47
Speaker 1: that system. Not statements that are hard to prove, not
1:04:53
Speaker 1: statements that would take a very long time, statements that
1:04:56
Speaker 1: are genuinely, permanently, structurally unprovable, even though they are true.
1:05:04
Speaker 1: The system can see them, it cannot reach them. Gödel
1:05:09
Speaker 1: constructed his proof by encoding the statement into the system itself,
1:05:14
Speaker 1: producing a sentence that, that effectively says of itself that
1:05:18
Speaker 1: it cannot be proved in this system. If the system
1:05:22
Speaker 1: is consistent, the sentence is true, and if it is true,
1:05:27
Speaker 1: it cannot be proved. The system is incomplete, not because
1:05:32
Speaker 1: of any flaw in its design, but because of the
1:05:35
Speaker 1: nature of formal systems themselves. Penrose read this not as
1:05:41
Speaker 1: a curiosity about mathematical logic, but as a clue that
1:05:46
Speaker 1: about the nature of mind. Because a mathematician sitting outside
1:05:50
Speaker 1: the system can see that the Gödel sentence is true.
1:05:55
Speaker 1: The mathematician looks at the construction, understands why it works,
1:06:00
Speaker 1: and perceives its truth in a single act of insight
1:06:03
Speaker 1: that requires no proof within the system. The algorithm cannot
1:06:08
Speaker 1: do this. The algorithm is bound by the rules of
1:06:12
Speaker 1: the system. The mathematician is not. John Lucas, a philosopher
1:06:19
Speaker 1: at Oxford, made a similar argument in 1961. He wrote
1:06:26
Speaker 1: that Gödel' s theorem showed machines could never be minds because
1:06:31
Speaker 1: a mind can always step outside the rules that bind
1:06:35
Speaker 1: a machine. Penrose took Lucas's argument and sharpened it into physics.
1:06:42
Speaker 1: The question was not just whether machines are minds. The
1:06:46
Speaker 1: question was what kind of physical process could produce the
1:06:50
Speaker 1: kind of non-algorithmic insight that Godel's theorem seems to require.
1:06:57
Speaker 1: If your brain were simply running a very complicated program,
1:07:01
Speaker 1: you would be subject to your own Godel limitations. You
1:07:05
Speaker 1: would have true beliefs you could never justify. But the
1:07:10
Speaker 1: mathematician can justify them. at least in the moment of
1:07:15
Speaker 1: perceiving the Gödel sentence as truth. Something else is happening,
1:07:19
Speaker 1: Penrose argued, something the physics of 1989 could not yet describe.
1:07:26
Speaker 1: He did not stop at the criticism. He proposed the replacement.
1:07:31
Speaker 1: If consciousness requires a non-computable process, and if non-computable processes
1:07:37
Speaker 1: are not found in classical physics or in standard quantum mechanics...
1:07:43
Speaker 1: Then they must come from somewhere that neither theory reaches.
1:07:48
Speaker 1: Penrose pointed to the boundary between quantum mechanics and general relativity,
1:07:54
Speaker 1: the place where the two great frameworks of modern physics
1:07:58
Speaker 1: have never been reconciled. In standard quantum mechanics, superpositions collapse
1:08:05
Speaker 1: when a system is observed or disturbed by its environment.
1:08:10
Speaker 1: The collapse is random. It picks one outcome from the
1:08:14
Speaker 1: probability distribution, and there is no deeper explanation for which
1:08:19
Speaker 1: outcome is chosen. The randomness is fundamental. But randomness is
1:08:25
Speaker 1: not the same as non-computability. A random process is still,
1:08:31
Speaker 1: in principle, simulable. Penrose proposed something different. He called it
1:08:37
Speaker 1: objective reduction, and he abbreviated it, or The idea is
1:08:43
Speaker 1: that quantum superpositions are not collapsed by environmental disturbance or
1:08:48
Speaker 1: by measurement, but by a threshold in spacetime geometry itself.
1:08:55
Speaker 1: Massive objects curve spacetime. A superposition of a mass in
1:09:01
Speaker 1: two different positions means spacetime is simultaneously curved in two
1:09:07
Speaker 1: different ways, which is geometrically unstable. At some threshold of
1:09:12
Speaker 1: gravitational difference, the superposition becomes untenable and collapses, not randomly,
1:09:19
Speaker 1: but but through a process rooted in the structure of
1:09:22
Speaker 1: space-time at the smallest scale we can define, the Planck scale,
1:09:28
Speaker 1: at roughly 10 to the power of negative 35 meters.
1:09:33
Speaker 1: The collapse is not computable. It reaches into a level
1:09:37
Speaker 1: of physics that no algorithm can simulate, because that level
1:09:42
Speaker 1: of physics does not yet have a theory. The non-computability
1:09:47
Speaker 1: of consciousness, on this view, is not a bug. It
1:09:51
Speaker 1: is a window into the deepest geometry of reality. The
1:09:56
Speaker 1: threshold matters enormously when you bring it to biology. The
1:10:02
Speaker 1: time it takes for a superposition to collapse under objective
1:10:06
Speaker 1: reduction depends on the mass in superposition. Larger masses curve
1:10:12
Speaker 1: spacetime more. The gravitational difference between the two branches of
1:10:16
Speaker 1: the superposition becomes intolerable more quickly, and collapse happens faster.
1:10:23
Speaker 1: For very small masses, collapse takes a very long time.
1:10:28
Speaker 1: For masses near the Planck scale, collapse is essentially instantaneous.
1:10:35
Speaker 1: For tubulin dimers in microtubules, each dimer having a mass
1:10:40
Speaker 1: of roughly 110 kilodaltons Penrose calculated that if a significant
1:10:47
Speaker 1: number of dimers are simultaneously in superposition, the collapse time
1:10:52
Speaker 1: falls in the range of around 25 milliseconds. That number
1:10:56
Speaker 1: is not arbitrary. 25 milliseconds corresponds to a frequency of
1:11:03
Speaker 1: 40 cycles per second, 40 hertz. gamma oscillations, the brainwave
1:11:09
Speaker 1: frequency that has been most consistently associated with conscious awareness
1:11:14
Speaker 1: and attentional binding across decades of electroencephalography research. And that
1:11:22
Speaker 1: is not where the argument sat in 1989. It is
1:11:26
Speaker 1: where it arrived in 1996, when Penrose joined forces with
1:11:32
Speaker 1: Stuart Hameroff, the anesthesiologist from Tucson, who had spent a
1:11:37
Speaker 1: decade arguing that microtubules were the brain's true computational substrate.
1:11:43
Speaker 1: Together they published Orchestrated Objective Reduction, ORCHOR, in a paper
1:11:49
Speaker 1: in Physics of Life Reviews. The theory proposed that microtubules
1:11:54
Speaker 1: inside neurons orchestrate quantum superpositions across their tubulin lattice, that
1:12:00
Speaker 1: those superpositions are tuned and structured by biological processes, at
1:12:06
Speaker 1: the cellular level, and that when they collapse through objective reduction,
1:12:11
Speaker 1: the collapse is not random noise, but an event with
1:12:14
Speaker 1: genuine physical content, non-computable, rooted in Planck scale geometry, and
1:12:21
Speaker 1: constitutive of conscious experience rather than merely correlated with it.
1:12:27
Speaker 1: The word orchestrated carries most of the weight. Random quantum
1:12:32
Speaker 1: collapses scattered through billions of microtubules would produce nothing coherent.
1:12:39
Speaker 1: Orch or requires that the collapses are biologically coordinated, shaped
1:12:44
Speaker 1: by synaptic inputs and cellular biochemistry, so that the quantum
1:12:50
Speaker 1: events happening at the nanometer scale inside individual protein tubes
1:12:57
Speaker 1: are coupled to the neural dynamics happening at the scale
1:13:00
Speaker 1: of the whole brain. It is an extraordinarily ambitious claim
1:13:06
Speaker 1: It requires quantum mechanics, general relativity, cell biology, and neuroscience
1:13:14
Speaker 1: to all be pointing at the same place, and it
1:13:17
Speaker 1: requires each of those fields to extend beyond its current
1:13:22
Speaker 1: confirmed reach. But here is the thing that kept the
1:13:26
Speaker 1: theory alive through two decades of dismissal. In 1996, Penrose
1:13:33
Speaker 1: and Hameroff published five specific experimental predictions. Microtubules should show
1:13:39
Speaker 1: quantum coherence at biological temperatures. Anesthetics should act on microtubules specifically.
1:13:47
Speaker 1: Drugs that stabilize microtubules should affect anesthesia thresholds. Gamma oscillations
1:13:55
Speaker 1: should correlate with microtubule dynamics. And signatures of quantum gravity...
1:14:02
Speaker 1: should in principle be detectable in the precise timing of
1:14:06
Speaker 1: neural events. These are not vague philosophical assertions. They are
1:14:12
Speaker 1: predictions that could be tested and falsified. By 2023, four
1:14:18
Speaker 1: of the five had received at least partial experimental support.
1:14:24
Speaker 1: The quantum coherence in tubulin is now measured data. The
1:14:29
Speaker 1: anesthetic action on microtubule quantum signatures has been shown in
1:14:34
Speaker 1: cell-free preparations. The Taxol experiment in rats showed the microtubule
1:14:42
Speaker 1: stabilization effect on anesthesia thresholds. The gamma oscillation correlation with
1:14:48
Speaker 1: microtubule dynamics has been documented in multiple independent studies. The
1:14:54
Speaker 1: fifth prediction, quantum gravity signatures in neural timings, remains beyond
1:15:00
Speaker 1: current experimental reach, though proposals exist for how to test it.
1:15:05
Speaker 1: The theory was called fantasy for 20 years by people
1:15:09
Speaker 1: whose objection was reasonable. Warm brains cannot sustain quantum coherence.
1:15:15
Speaker 1: But that objection assumed something about biology that the photosynthesis
1:15:20
Speaker 1: experiments and the tubulin spectroscopy have since put under serious pressure.
1:15:27
Speaker 1: A theory that correctly predicts new experimental results does not
1:15:32
Speaker 1: graduate automatically into truth. But it does graduate out of
1:15:38
Speaker 1: the category of fantasy and into the category of hypothesis
1:15:43
Speaker 1: worth taking seriously, which is how ideas at the edge
1:15:47
Speaker 1: of science earn the right to stay. Yet the loudest
1:15:51
Speaker 1: and most technically sophisticated opposition to Orch or came not
1:15:56
Speaker 1: from philosophers, but from physicists who sat down and calculated
1:16:01
Speaker 1: exactly how fast the brain's thermal environment would destroy any
1:16:06
Speaker 1: quantum superposition. And the man who made that calculation most
1:16:11
Speaker 1: forcefully is a noble laureate whose number, 10 to the
1:16:15
Speaker 1: power of negative 13 seconds, is still the first thing
1:16:20
Speaker 1: every quantum consciousness researcher knows. has to answer every single
1:16:25
Speaker 1: morning they come to work. That number came from a
1:16:29
Speaker 1: paper published in the year 2000 in Physical Review E,
1:16:35
Speaker 1: and it was written by someone who had no particular
1:16:39
Speaker 1: stake in consciousness research, no theory to defend, and no
1:16:44
Speaker 1: patience for what he considered wishful thinking dressed up in
1:16:49
Speaker 1: the language of quantum mechanics. Max Tegmark is a cosmologist.
1:16:56
Speaker 1: His day job, in the year 2000 and in every
1:17:00
Speaker 1: year since, has been mapping the cosmic microwave background, the
1:17:05
Speaker 1: faint thermal glow left over from the early universe, and
1:17:09
Speaker 1: working out the large-scale structure of space and time. He
1:17:14
Speaker 1: is not a neuroscientist, and he was not trying to
1:17:18
Speaker 1: build a theory of mind. He was trying to apply
1:17:22
Speaker 1: a basic physical calculation to a claim he found implausible,
1:17:28
Speaker 1: and he wanted to find out whether the numbers supported
1:17:32
Speaker 1: the implausibility he already suspected. The paper was titled The
1:17:38
Speaker 1: Importance of Quantum Decoherence in Brain Processes, and it ran
1:17:44
Speaker 1: to a handful of pages in a physics journal. and
1:17:47
Speaker 1: it landed in the consciousness-science community like a stone dropped
1:17:52
Speaker 1: into still water. The calculation itself is not exotic. Decoherence time,
1:18:00
Speaker 1: the interval before a quantum superposition collapses into a definite
1:18:04
Speaker 1: classical state because of interactions with its environment, can be
1:18:09
Speaker 1: estimated from a handful of physical quantities. You need the
1:18:13
Speaker 1: temperature of the environment— the mass of the object in superposition,
1:18:19
Speaker 1: the nature of the surrounding medium, and the coupling strength
1:18:23
Speaker 1: between the quantum system and that medium. Tegmark plugged in
1:18:28
Speaker 1: the numbers for a neuron. Temperature, 310 Kelvin, normal body temperature.
1:18:36
Speaker 1: Surrounding medium, water, which is what fills the space between
1:18:41
Speaker 1: and around cellular structures. coupling, strong, because water molecules are
1:18:48
Speaker 1: polar and collide with protons. structures at rates of roughly
1:18:52
Speaker 1: 10 trillion times per second at that collision rate each
1:18:58
Speaker 1: collision acts as a measurement in the quantum mechanical sense
1:19:03
Speaker 1: interrogating the state of the system and forcing it out
1:19:06
Speaker 1: of superposition For a superposition of ion positions inside a neuron,
1:19:12
Speaker 1: Tegmark got a decoherence time of 10 to the power
1:19:16
Speaker 1: of negative 13 seconds. That is one-tenth of a picosecond.
1:19:23
Speaker 1: A picosecond is one-trillionth of a second. The brain's gamma oscillations,
1:19:28
Speaker 1: the 40 hertz rhythms that Penrose and Hameroff proposed as
1:19:32
Speaker 1: the timescale of conscious processing, cycle once every 25 milliseconds.
1:19:36
Speaker 1: 25 milliseconds is 250 billion times longer than 10 to
1:19:44
Speaker 1: the negative 13 seconds. The gap between what quantum coherence
1:19:49
Speaker 1: could last and what the brain would need it to
1:19:52
Speaker 1: last was not close. It was not even in the
1:19:55
Speaker 1: same universe of measurement. It was 13 orders of magnitude,
1:20:01
Speaker 1: the same kind of gap that separates the diameter of
1:20:04
Speaker 1: an atomic nucleus from the height of a person. For
1:20:09
Speaker 1: tubulin conformational superpositions specifically, the number was worse. Tegmark estimated
1:20:16
Speaker 1: decoherence times of 10 to the power of negative 20
1:20:20
Speaker 1: seconds for certain tubulin state superpositions, 20 orders of magnitude
1:20:26
Speaker 1: below the gamma oscillation timescale. The conclusion he drew was
1:20:32
Speaker 1: unambiguous and stated plainly. Quantum superpositions in neural structures are
1:20:38
Speaker 1: would collapse long before they could influence any biological process
1:20:43
Speaker 1: that operates on timescales relevant to cognition. The brain is
1:20:49
Speaker 1: too warm, too wet, and too densely coupled to its
1:20:54
Speaker 1: thermal environment to be a quantum computer in any meaningful sense.
1:21:01
Speaker 1: The paper was peer-reviewed. The mathematics was correct. The physical
1:21:07
Speaker 1: reasoning was sound, and for most physicists who glanced at it,
1:21:13
Speaker 1: that was the end of the discussion. But critics had
1:21:17
Speaker 1: one objection left, and it was a good one. Tegmark's
1:21:22
Speaker 1: calculation treated the quantum systems in the brain as if
1:21:26
Speaker 1: they were isolated particles sitting in a bath of water,
1:21:30
Speaker 1: coupled to that bath through direct thermal contact with no
1:21:34
Speaker 1: intermediate structure. That is a reasonable first approximation for many
1:21:39
Speaker 1: physical systems. It is not, as the photosynthetic coherence experiments
1:21:46
Speaker 1: published seven years later would demonstrate, a reasonable model for
1:21:51
Speaker 1: a quantum system embedded in a biological protein. The difference
1:21:57
Speaker 1: is architectural. When a quantum state is encoded in the
1:22:01
Speaker 1: global topology of a structured system, rather than in the
1:22:05
Speaker 1: local degree of freedom of a single particle, individual thermal
1:22:10
Speaker 1: collisions do not collapse it. A single water molecule bouncing
1:22:16
Speaker 1: off the surface of a microtubule lattice and transferring a
1:22:20
Speaker 1: tiny amount of thermal energy does not measure the globally
1:22:24
Speaker 1: encoded quantum state any more than a raindrop falling on
1:22:29
Speaker 1: a vinyl record measures the music encoded in its grooves.
1:22:34
Speaker 1: The record's information is in the pattern of the whole,
1:22:38
Speaker 1: not in the surface chemistry of any one point. Knock
1:22:42
Speaker 1: a few molecules off the surface and the music survives.
1:22:48
Speaker 1: This is the principle behind topological protection in quantum computing,
1:22:55
Speaker 1: a field that has grown enormously since the year 2000.
1:22:58
Speaker 1: Topological quantum codes are including surface codes and related architectures,
1:23:07
Speaker 1: store quantum information in properties of a system that are
1:23:11
Speaker 1: invariant under local perturbations. An error at one site does
1:23:18
Speaker 1: not corrupt the global quantum state because the state is
1:23:22
Speaker 1: not localized at any site. It is distributed across the
1:23:27
Speaker 1: geometry of the whole structure. The only way to destroy
1:23:31
Speaker 1: it is to perturb the entire global topology simultaneously, which
1:23:37
Speaker 1: requires a coordinated disturbance far larger than ordinary thermal noise.
1:23:43
Speaker 1: Tubulin lattices, as the spectroscopy and crystallography work published between
1:23:51
Speaker 1: 2013 and 2022 gradually established, have a geometric regularity that
1:23:57
Speaker 1: extends over distances of micrometers. which is enormous by molecular standards.
1:24:05
Speaker 1: The tryptophan residues inside tubulin are spaced at intervals close
1:24:10
Speaker 1: to the Forster energy transfer distance, meaning they are arranged
1:24:14
Speaker 1: at precisely the spacing needed for quantum resonance energy transfer
1:24:19
Speaker 1: to operate efficiently. That spacing is not random. It is
1:24:24
Speaker 1: the product of protein folding under evolutionary pressure over timescales
1:24:30
Speaker 1: measured in billions of years, and it produces a lattice
1:24:34
Speaker 1: geometry that computational analysis has shown to match the topology
1:24:40
Speaker 1: of a quantum error correcting code. In 2023, a response
1:24:45
Speaker 1: paper in Physics of Life Reviews Co., authored by Penrose,
1:24:50
Speaker 1: Hameroff and colleagues took Tegmark's framework seriously, accepted his basic
1:24:57
Speaker 1: physical reasoning, and recalculated the decoherence times for quantum states
1:25:03
Speaker 1: encoded in topologically protected configurations of the tubulin lattice rather
1:25:09
Speaker 1: than in isolated tubulin dimers. The result was decoherence times
1:25:14
Speaker 1: in the range of tens to hundreds of milliseconds consistent
1:25:19
Speaker 1: with the gamma oscillation timescale and with the duration of
1:25:23
Speaker 1: quantum coherence observed in photosynthetic systems. Tegmark's response to all
1:25:31
Speaker 1: of this has been careful and worth quoting in its texture.
1:25:36
Speaker 1: In a 2014 interview, he acknowledged that the photosynthetic coherence
1:25:42
Speaker 1: experiments had meaningfully changed what could be claimed about warm
1:25:48
Speaker 1: biological quantum systems. He remained skeptical of Orch, or as
1:25:54
Speaker 1: a specific theory of consciousness, skeptical enough that his personal
1:25:59
Speaker 1: assessment had not shifted dramatically, but he agreed that the
1:26:04
Speaker 1: question of whether biological protein environments could sustain quantum coherence
1:26:10
Speaker 1: beyond what naive thermal calculations predict was no longer settled.
1:26:17
Speaker 1: That is a significant concession from the man who wrote
1:26:20
Speaker 1: the paper that was supposed to settle it. The distinction
1:26:25
Speaker 1: Tegmark was navigating was is worth sitting with for a moment,
1:26:29
Speaker 1: because it is the distinction this entire debate turns on.
1:26:35
Speaker 1: A calculation that correctly describes the behavior of a quantum
1:26:39
Speaker 1: system in water is not wrong. It is incomplete if
1:26:43
Speaker 1: the quantum system is not actually in water in the
1:26:47
Speaker 1: relevant sense, but is instead embedded in a crystalline protein
1:26:52
Speaker 1: lattice whose geometry actively channels thermal fluctuations in ways that
1:26:57
Speaker 1: protect rather than destroy quantum states. The calculation was not
1:27:04
Speaker 1: an error. It was a model of the wrong geometry,
1:27:08
Speaker 1: applied with perfect rigor to the wrong structure. The difference
1:27:12
Speaker 1: between a quantum system sitting in water and a quantum
1:27:16
Speaker 1: system protected by three billion years of evolved protein architecture
1:27:21
Speaker 1: is the difference between a candle flame and a laser.
1:27:25
Speaker 1: Both involve photons. Both produce light. The comparison ends there entirely.
1:27:32
Speaker 1: Decoherence times and protein geometry are theoretical arguments, and theory
1:27:38
Speaker 1: alone was never going to settle this debate. The field
1:27:42
Speaker 1: needed an experiment, a real measurement in real brains that
1:27:47
Speaker 1: would show whether quantum effects in microtubules actually influence the
1:27:52
Speaker 1: moment consciousness switches off. That experiment was run not in
1:27:58
Speaker 1: a physics department, but in an operating room in Arizona
1:28:02
Speaker 1: with anesthetized rats and a drug originally developed to fight cancer.
1:28:08
Speaker 1: And the man who had predicted its outcome waited 27
1:28:12
Speaker 1: years to see the data come in. Stuart Hameroff was
1:28:18
Speaker 1: born in 1947, which means that in 2023, when the
1:28:20
Speaker 1: paper finally arrived in his inbox, He was 76 years old.
1:28:29
Speaker 1: He had spent the better part of four decades arguing
1:28:32
Speaker 1: that the protein tubes inside neurons were not passive scaffolding,
1:28:37
Speaker 1: but active participants in the process that produces organs. awareness.
1:28:41
Speaker 1: He had co-authored papers with a Nobel laureate, organized conferences,
1:28:46
Speaker 1: debated physicists, absorbed the contempt of colleagues who considered the
1:28:51
Speaker 1: whole project embarrassing, and continued. The data point he had
1:28:56
Speaker 1: been waiting for was not glamorous. It involved rats, a
1:29:00
Speaker 1: cancer drug, and a gas. But it was real, and
1:29:04
Speaker 1: it was on the right side of the prediction. The
1:29:07
Speaker 1: drug is called Taxol, or by its generic name Paclitaxel,
1:29:12
Speaker 1: and it comes from the bark of the Pacific yew tree.
1:29:16
Speaker 1: Oncologists use it to stop cancer cells from dividing, and
1:29:20
Speaker 1: the mechanism is specific. Taxol binds to the inner wall
1:29:26
Speaker 1: of microtubules, and locks them in place. Microtubules under normal
1:29:32
Speaker 1: conditions are extraordinarily dynamic. They grow from one end and
1:29:39
Speaker 1: shrink from the other in a continuous cycle called dynamic instability,
1:29:45
Speaker 1: assembling and disassembling thousands of times over the course of
1:29:49
Speaker 1: a single day. Cancer cells depend on this dynamic behavior
1:29:54
Speaker 1: to pull chromosomes apart during cell division. Taxol freezes the process.
1:30:00
Speaker 1: It does not dissolve the microtubules. It does not poison
1:30:05
Speaker 1: the tubulin protein. It simply holds the assembled lattice rigid,
1:30:10
Speaker 1: preventing it from breaking down. For cancer treatment, this is
1:30:14
Speaker 1: the point. For the experiment Hameroff and his colleagues had
1:30:18
Speaker 1: in mind, it was a precise molecular tool for a
1:30:21
Speaker 1: different purpose entirely. The logic of the experiment was straightforward.
1:30:28
Speaker 1: If microtubules are simply structural scaffolding inside neurons, stabilizing them
1:30:34
Speaker 1: with taxol should make no difference whatsoever to how quickly
1:30:38
Speaker 1: a rat loses consciousness under anesthetic. Scaffolding is scaffolding. Freeze
1:30:45
Speaker 1: it in place, or let it fluctuate, and the neuron
1:30:49
Speaker 1: still fires, the synapse still transmits, the network still processes.
1:30:56
Speaker 1: But if the quantum coherent states of the tubulin lattice
1:31:00
Speaker 1: are actually involved in sustaining consciousness, then stabilizing that lattice
1:31:06
Speaker 1: should change the picture. A more rigid, more ordered lattice
1:31:11
Speaker 1: would maintain quantum coherence for longer. It would be harder
1:31:15
Speaker 1: to disrupt. The anesthetic would have to work harder against
1:31:20
Speaker 1: a more resistant system, and the rat would take longer
1:31:24
Speaker 1: to go under. That is exactly what happened. The 2023
1:31:29
Speaker 1: paper in Neuroscience of Consciousness, authored by Craddock, Hameroff, and colleagues,
1:31:36
Speaker 1: showed that rats treated with Taxol required 23% longer exposure
1:31:42
Speaker 1: to isoflurane anesthetic before reaching what researchers call the loss-of-writing reflex.
1:31:51
Speaker 1: Loss-of-writing reflex is the standard measure for unconsciousness In rodent experiments,
1:31:58
Speaker 1: a conscious rat placed on its back will immediately right itself.
1:32:03
Speaker 1: An anesthetized rat will not. The endpoint is clean and reproducible,
1:32:09
Speaker 1: and the taxol-treated animals were crossing it significantly later than
1:32:13
Speaker 1: the untreated controls. The result was replicated across three separate
1:32:19
Speaker 1: cohorts of animals. The statistical threshold was met with a
1:32:24
Speaker 1: p-value below 0.05. The dose-response relationship was monotonic, meaning that
1:32:31
Speaker 1: rats given more taxol took longer to lose consciousness than
1:32:38
Speaker 1: rats given less, and rats given less took longer than controls.
1:32:44
Speaker 1: A monotonic dose-response curve is one of the most reliable
1:32:48
Speaker 1: signatures of a genuine pharmacological effect rather than a statistical artifact,
1:32:55
Speaker 1: because it means the outcome tracks the intervention in a
1:32:59
Speaker 1: graded and orderly way. Critics had one objection left, and
1:33:05
Speaker 1: it was a good one. Could Taxol be affecting anesthetic
1:33:10
Speaker 1: sensitivity through some entirely classical mechanism or perhaps by altering
1:33:16
Speaker 1: the mechanical properties of cell membranes or by changing how
1:33:20
Speaker 1: anesthetic molecules diffuse through neural tissue. This is a serious question,
1:33:27
Speaker 1: and the researchers took it seriously. The answer they offered
1:33:31
Speaker 1: came from a complementary experiment using a different drug with
1:33:36
Speaker 1: the opposite effect. Colcocine is a plant-derived compound that has
1:33:43
Speaker 1: been used since antiquity to treat gout, and it does
1:33:48
Speaker 1: to microtubules what Taxol does not. Rather than stabilizing them,
1:33:54
Speaker 1: colcocine disassembles them. It binds tubulin dimers and prevents them
1:34:00
Speaker 1: from incorporating into the growing lattice, causing microtubules to depolymerize.
1:34:07
Speaker 1: If the logic of the Taxol experiment holds— Colchicine should
1:34:11
Speaker 1: produce the mirror image result. Animals with fewer intact microtubules,
1:34:19
Speaker 1: with less quantum coherent tubulin lattice available, should be more
1:34:24
Speaker 1: susceptible to anesthetic, not less. They should lose consciousness faster
1:34:31
Speaker 1: and at lower doses. And they did. Colcassine-treated rats crossed
1:34:37
Speaker 1: the loss of writing reflex endpoint earlier and at lower
1:34:42
Speaker 1: anesthetic concentrations than controls. The symmetry of the two results
1:34:48
Speaker 1: is difficult to explain if microtubules are doing nothing relevant
1:34:53
Speaker 1: to consciousness. If they are passive scaffolding, then disrupting them
1:34:58
Speaker 1: in opposite directions should produce no difference in anesthetic sensitivity
1:35:04
Speaker 1: either way. The fact that stabilizing them delays unconsciousness and
1:35:09
Speaker 1: depolymerizing them accelerates, it points toward a structure that is
1:35:14
Speaker 1: actively involved in the state being switched off. A parallel
1:35:18
Speaker 1: line of evidence came from a group in Japan led
1:35:22
Speaker 1: by Anirban Bandiopadhyay, working with microtubules not inside living brains
1:35:28
Speaker 1: but in cell-free preparations. isolated protein assemblies in a laboratory dish.
1:35:35
Speaker 1: Bandiopadier's group had previously shown that microtubules display quantum interference
1:35:41
Speaker 1: patterns in their electrical conductance, a direct signature of quantum
1:35:47
Speaker 1: superposition rather than classical current flow. In their anesthetic experiments,
1:35:53
Speaker 1: they exposed isolated microtubules to anesthetic molecules and measured what changed.
1:36:00
Speaker 1: The result was was precise and telling. The classical electrical
1:36:05
Speaker 1: conductance of the microtubules was unaffected. The bulk structure remained intact.
1:36:12
Speaker 1: The protein did not fall apart. But the quantum interference
1:36:16
Speaker 1: signatures vanished. The anesthetic suppressed specifically the quantum coherent channel
1:36:23
Speaker 1: of conductance while leaving the classical channel untouched. whatever the
1:36:29
Speaker 1: anesthetic was doing to the microtubule. It was not dissolving
1:36:34
Speaker 1: the protein, it was silencing the quantum process running inside it.
1:36:40
Speaker 1: Hameroff described the combined results as the most important experimental
1:36:46
Speaker 1: development of his career. He was also careful in the
1:36:50
Speaker 1: same breath to note that the Taxol study had not
1:36:54
Speaker 1: yet been independently replicated and and that independent replication is
1:36:59
Speaker 1: the threshold that separates a promising finding from an established one.
1:37:05
Speaker 1: His critics made the same point, and on this particular
1:37:09
Speaker 1: issue the two sides agreed completely. The experiment needs to
1:37:14
Speaker 1: be run again, in a different laboratory, by researchers with
1:37:19
Speaker 1: no stake in the outcome. That has not happened yet.
1:37:25
Speaker 1: What has happened is that a theory which spent 27
1:37:28
Speaker 1: years as a source of raised eyebrows now has a
1:37:33
Speaker 1: data point attached to it. Orchestrated objective reduction predicted, in 1996,
1:37:40
Speaker 1: that drugs stabilizing microtubules would raise the threshold for anesthesia
1:37:47
Speaker 1: and that drugs disrupting microtubules would lower it. A 2023
1:37:54
Speaker 1: peer-reviewed paper showed both effects in living animals, with the
1:37:59
Speaker 1: dose-response curves going in the predicted directions. One experiment in
1:38:04
Speaker 1: rats is not a revolution, and no reasonable scientist would
1:38:08
Speaker 1: claim otherwise. But a theory that makes a novel prediction,
1:38:13
Speaker 1: waits 27 years for someone to test it, and then
1:38:17
Speaker 1: finds the result pointing the right way, has crossed a
1:38:21
Speaker 1: line that purely speculative theories have not crossed. It has
1:38:27
Speaker 1: made contact with the world. The question that experiment cannot
1:38:33
Speaker 1: answer is a different kind of question entirely. It tells
1:38:38
Speaker 1: you that microtubules matter for the timing of consciousness. It
1:38:42
Speaker 1: does not tell you why the timing of anything feels
1:38:46
Speaker 1: like something. The how and the why are are not
1:38:50
Speaker 1: the same question, and the person who made that distinction
1:38:54
Speaker 1: most clearly did it not in an operating room or
1:38:58
Speaker 1: a physics department, but in a conference room in Tucson
1:39:03
Speaker 1: in 1995, and the room went quiet in a way
1:39:07
Speaker 1: that suggested everyone present already knew he was identifying something real.
1:39:14
Speaker 1: His name was David Chalmers, and he was thirty years old,
1:39:19
Speaker 1: and what he said that afternoon in Tucson changed the
1:39:22
Speaker 1: shape of a conversation that had been running for centuries
1:39:26
Speaker 1: without anyone finding its center. The conference was called Toward
1:39:33
Speaker 1: a Science of Consciousness, the first of its kind held
1:39:37
Speaker 1: in April of 1995 at the University of Arizona. The
1:39:43
Speaker 1: room held neuroscientists, philosophers, physicists, and a handful of anesthesiologists
1:39:51
Speaker 1: who had driven up from the university hospital a few
1:39:54
Speaker 1: blocks away. Chalmers stood up and told them that everything
1:39:59
Speaker 1: they had been working on, the neural correlates of attention,
1:40:03
Speaker 1: the mechanisms of working memory, the binding of sensory streams
1:40:08
Speaker 1: into unified perception, all of it was the easy problem.
1:40:13
Speaker 1: Not easy in the sense of simple, Easy in the
1:40:16
Speaker 1: sense that you could see the shape of how an
1:40:19
Speaker 1: answer might eventually arrive. You could imagine building a better
1:40:24
Speaker 1: imaging machine, running a better experiment, mapping another circuit. The
1:40:30
Speaker 1: easy problems yield to the tools science already has. The
1:40:35
Speaker 1: hard problem is different in kind, not in degree. It
1:40:40
Speaker 1: is the question of why any physical process produces subjective
1:40:44
Speaker 1: experience at all. Why does the firing of neurons feel
1:40:49
Speaker 1: like anything? Why is there something it is like to
1:40:53
Speaker 1: see red, to hear a note of music, to feel
1:40:57
Speaker 1: the specific texture of grief? A machine can detect the
1:41:01
Speaker 1: wavelength of red light and classify it and respond to
1:41:06
Speaker 1: it without ever experiencing redness. Nothing in the laws of
1:41:11
Speaker 1: physics as currently written forbids a brain from processing information
1:41:17
Speaker 1: about color in complete inner darkness, with no felt quality
1:41:23
Speaker 1: attached to the processing at all. The fact that it
1:41:27
Speaker 1: does not work that way, the fact that you are
1:41:30
Speaker 1: experiencing this moment rather than merely computing it, is the
1:41:35
Speaker 1: thing that needs explaining, and classical neuroscience has no principled
1:41:41
Speaker 1: account of it. Chalmers published his argument that same year
1:41:46
Speaker 1: in the Journal of Consciousness Studies in a paper called
1:41:51
Speaker 1: Facing Up to the Problem of Consciousness. It was careful, precise,
1:41:57
Speaker 1: and deliberately narrow. He was not claiming that consciousness is supernatural.
1:42:03
Speaker 1: He was not denying that the brain causes experience. He
1:42:07
Speaker 1: was pointing out that the causal story neuron fires, chemical releases,
1:42:13
Speaker 1: signal propagates, tells you everything about the mechanism and nothing
1:42:18
Speaker 1: about why the mechanism is accompanied by felt experience rather
1:42:24
Speaker 1: than nothing at all. That gap between the third-person description
1:42:28
Speaker 1: of a brain and the first-person fact of being inside
1:42:32
Speaker 1: one is what he called the explanatory gap, and thirty
1:42:37
Speaker 1: years of subsequent work has not closed it. What classical
1:42:42
Speaker 1: computational neuroscience offers in response is mostly a change of subject.
1:42:48
Speaker 1: It explains what information the brain integrates, which regions activate
1:42:53
Speaker 1: during various experiences, how attention selects certain signals over others.
1:43:00
Speaker 1: These are genuine discoveries. They are also answers to questions
1:43:05
Speaker 1: slightly different from the one Chalmers asks. A sufficiently detailed
1:43:10
Speaker 1: map of every neuron firing during your experience of the
1:43:14
Speaker 1: color red does not explain why there is an experience
1:43:18
Speaker 1: at all rather than a very accurate color detection system
1:43:23
Speaker 1: operating in the dark. Giulio Tononi at the University of
1:43:27
Speaker 1: Wisconsin took this seriously and built a theory around it.
1:43:32
Speaker 1: Integrated Information Theory published first in BMC Neuroscience in 2004
1:43:39
Speaker 1: and developed in considerable mathematical detail in subsequent papers, proposes
1:43:46
Speaker 1: that consciousness is not produced by the brain but is
1:43:50
Speaker 1: identical to a particular property of any physical system. That
1:43:55
Speaker 1: property is integrated information, which Tononi called phi. A system
1:44:01
Speaker 1: has high phi when its parts share information in a
1:44:04
Speaker 1: way that cannot be decomposed into independent sub-processes, when the
1:44:09
Speaker 1: whole contains more information than the sum of its parts.
1:44:14
Speaker 1: Tononi's proposal is that any system with sufficiently high phi,
1:44:19
Speaker 1: regardless of what it is made of, has experience. The
1:44:23
Speaker 1: brain has high phi. A simple grid of independent pixels
1:44:27
Speaker 1: has low phi. A sophisticated but modular computer might have
1:44:33
Speaker 1: surprisingly low phi if its processing can be cleanly separated
1:44:38
Speaker 1: into parallel streams. The theory is elegant, and it takes
1:44:44
Speaker 1: the hard problem seriously as a starting constraint rather than
1:44:49
Speaker 1: a result to be derived later. Its difficulty is that
1:44:54
Speaker 1: it implies experience is everywhere phi i is non-zero. which
1:44:59
Speaker 1: means simple systems have simple experiences and the universe contains
1:45:05
Speaker 1: an enormous amount of faint experience distributed across every integrated
1:45:10
Speaker 1: physical system. This is a form of panpsychism, and many
1:45:14
Speaker 1: philosophers and scientists find it more troubling than the problem
1:45:18
Speaker 1: it solves. Max Tegmark published an estimate in Close Computational
1:45:24
Speaker 1: Biology in 2014 suggesting the brain's phi is high enough
1:45:30
Speaker 1: to be consistent with consciousness under it. But he argued
1:45:34
Speaker 1: that this conclusion does not require quantum mechanics in any
1:45:38
Speaker 1: essential way. A classical brain with the right integration structure
1:45:44
Speaker 1: would do just as well. But here is where the
1:45:47
Speaker 1: quantum shortcut becomes interesting rather than merely technical. Quantum entanglement
1:45:54
Speaker 1: is is not a faster way of doing classical computation.
1:45:59
Speaker 1: It is a different kind of integration. When two particles
1:46:04
Speaker 1: are entangled, measuring one instantly constrains the state of the other,
1:46:09
Speaker 1: regardless of the distance between them. The information shared between
1:46:15
Speaker 1: them is not carried by any signal traveling through space.
1:46:20
Speaker 1: It is a global property of the joint system that
1:46:23
Speaker 1: cannot be decomposed into local facts about each particle separately.
1:46:29
Speaker 1: That is exactly the kind of irreducible integration that Tononi's
1:46:34
Speaker 1: phi is designed to measure, and several theorists have proposed
1:46:38
Speaker 1: that quantum entanglement could dramatically increase phi in biological systems
1:46:44
Speaker 1: by creating correlations across the whole network that no classical
1:46:50
Speaker 1: synaptic wiring could replicate. if microtubules are maintaining quantum coherence
1:46:57
Speaker 1: across a neuron. The integrated information of that neuron's internal
1:47:01
Speaker 1: state would be vastly higher than any classical estimate of
1:47:05
Speaker 1: its phi. Orchestrated objective reduction addresses the hard problem from
1:47:11
Speaker 1: a different angle entirely, and the angle is stranger. Penrose
1:47:16
Speaker 1: and Hameroff do not propose that quantum computation produces consciousness
1:47:22
Speaker 1: as an output, the way a classical computer might produce
1:47:26
Speaker 1: a file. They propose that the process of quantum collapse,
1:47:30
Speaker 1: objective reduction itself, is intrinsically experiential. The moment a quantum
1:47:37
Speaker 1: superposition collapses in a microtubule, that collapse is not merely
1:47:41
Speaker 1: a physical event with a felt quality attached to it afterward.
1:47:45
Speaker 1: The felt quality is the collapse. Experience is not generated
1:47:50
Speaker 1: by the event. Experience is what the event is, from
1:47:54
Speaker 1: the inside. This places phenomenal experience at the level of
1:47:58
Speaker 1: space-time geometry, at the Planck scale where quantum gravity operates,
1:48:04
Speaker 1: which is 10 to the power of minus 35 meters,
1:48:08
Speaker 1: the smallest length at which the current equations of physics
1:48:12
Speaker 1: mean anything. In a 2019 paper in Neuroquantology, Hameroff and
1:48:18
Speaker 1: Penrose argued that the particular felt qualities of experience, the
1:48:23
Speaker 1: specific warmth of warmth, the specific redness of red, correspond
1:48:29
Speaker 1: to specific geometric features of the Planck scale structure involved
1:48:33
Speaker 1: in each collapse event. This is panpsychism with a mechanism.
1:48:39
Speaker 1: It is not saying that rocks feel things. It is
1:48:42
Speaker 1: saying that the particular geometry of quantum gravity, collapse in
1:48:47
Speaker 1: biologically orchestrated microtubules, produces the particular felt textures of conscious experience.
1:48:55
Speaker 1: The hard problem does not dissolve under this account. Chalmers
1:48:59
Speaker 1: himself has written that quantum approaches to consciousness are worth
1:49:04
Speaker 1: taking seriously, but are not yet an explanation of of
1:49:08
Speaker 1: why physical processes feel like anything. A Planck-scale geometry event
1:49:15
Speaker 1: is still a physical process, and you can still ask
1:49:18
Speaker 1: why it feels like something rather than nothing. The gap
1:49:23
Speaker 1: does not close. What changes is its shape. Classical computation
1:49:29
Speaker 1: offers no physical process that is even a candidate for
1:49:32
Speaker 1: something intrinsically experiential. Quantum collapse, especially in the Penrose formulation,
1:49:39
Speaker 1: offers at least a process that is not purely informational,
1:49:43
Speaker 1: not purely mechanical, not purely describable from the outside. That
1:49:49
Speaker 1: is not a solution. It is a place where a
1:49:52
Speaker 1: solution might fit. And yet there is a possibility darker
1:49:58
Speaker 1: and stranger than any of this, which is that consciousness
1:50:02
Speaker 1: is not what the brain produces. but what the brain receives,
1:50:07
Speaker 1: that awareness might be a field property of space-time itself
1:50:12
Speaker 1: that biological quantum systems are tuned to detect, and the
1:50:16
Speaker 1: scientist who spent years measuring the electromagnetic field of the
1:50:21
Speaker 1: brain found something in the data that he could not.
1:50:25
Speaker 1: Explain away. Every neuron in your brain right now is
1:50:30
Speaker 1: both a receiver and a transmitter of electromagnetic fields. Not metaphorically. Literally,
1:50:38
Speaker 1: every time a neuron fires, it pushes charged ions across
1:50:42
Speaker 1: its membrane, and that movement of charge generates an electric
1:50:47
Speaker 1: field that radiates outward through the surrounding tissue, passing through
1:50:52
Speaker 1: neighboring neurons, through glial cells, through the fluid between them,
1:50:57
Speaker 1: touching everything within reach. And a neuroscientist at the University
1:51:02
Speaker 1: of Surrey spent years asking whether those fields, the ones
1:51:08
Speaker 1: that drift invisibly through the brain's warm interior, might themselves
1:51:13
Speaker 1: be a medium for conscious experience rather than just a
1:51:17
Speaker 1: shadow of it. John Joe McFadden is a molecular biologist
1:51:23
Speaker 1: and quantum biology theorist, co-author with Jim Al-Khalili of the
1:51:28
Speaker 1: 2015 book Life on the Edge, and one of the
1:51:31
Speaker 1: researchers who has spent two decades building the case that
1:51:35
Speaker 1: quantum effects in biology are not exotic exceptions, but foundational rules.
1:51:42
Speaker 1: In 2002, he published a two-part paper in the Journal
1:51:47
Speaker 1: of Consciousness Studies, proposing what he called the Conscious Electromagnetic
1:51:53
Speaker 1: Information Field Theory, which researchers in the field abbreviate to SEMI.
1:51:59
Speaker 1: The central claim of semi is not subtle. McFadden proposed
1:52:05
Speaker 1: that the brain's endogenous electromagnetic field, the field you can
1:52:10
Speaker 1: measure with electrodes pressed against the scalp during an EEG recording,
1:52:14
Speaker 1: is not a signature of consciousness produced somewhere else in
1:52:18
Speaker 1: the brain. It is consciousness. The field is not the readout.
1:52:24
Speaker 1: The field is the thing. To understand why this idea
1:52:29
Speaker 1: is more than a metaphor, you have to understand a
1:52:33
Speaker 1: problem that has haunted neuroscience for as long as the
1:52:36
Speaker 1: discipline has existed. It is called the binding problem. Your
1:52:41
Speaker 1: experience right now, if you are listening to this in
1:52:44
Speaker 1: a quiet room, is unified. The sound of this voice,
1:52:49
Speaker 1: the feeling of your breath, the dim awareness of whatever
1:52:53
Speaker 1: is around you, all of these arrive as one experience,
1:52:57
Speaker 1: not as a list of separate reports from separate brain regions.
1:53:02
Speaker 1: But the neurons processing each of those streams are physically
1:53:06
Speaker 1: distributed across different cortical areas, connected by synapses that transmit
1:53:12
Speaker 1: signals at speeds measured in milliseconds. There is no obvious
1:53:17
Speaker 1: place in the brain where all of those signals converge
1:53:21
Speaker 1: into a single felt moment. The binding problem asks what
1:53:26
Speaker 1: unifies them, Classical neural network models have no clean answer.
1:53:32
Speaker 1: Information in a classical network travels through wires, meaning axons
1:53:37
Speaker 1: and synapses, and those wires have finite speed and finite bandwidth.
1:53:43
Speaker 1: To bind distributed signals into a unified experience, you would
1:53:48
Speaker 1: need some central integration point, and the brain does not
1:53:52
Speaker 1: seem to have one, at least not in the way
1:53:54
Speaker 1: a classical computer does. has a central processor. McFadden's answer
1:54:01
Speaker 1: is that the electromagnetic field is that integrator. The speed
1:54:06
Speaker 1: of electromagnetic field propagation is the speed of light, which
1:54:12
Speaker 1: means field interactions across the entire volume of a human brain,
1:54:17
Speaker 1: roughly 1,400 cubic centimeters, are essentially instantaneous relative to any
1:54:24
Speaker 1: neural process measured in milliseconds. When billions of neurons fire
1:54:30
Speaker 1: in patterns across the brain, each one contributes to a
1:54:35
Speaker 1: shared electromagnetic field that encompasses the whole volume simultaneously. The
1:54:41
Speaker 1: field does not travel from one neuron to another the
1:54:45
Speaker 1: way a synaptic signal does. It is everywhere the brain is,
1:54:50
Speaker 1: all at once. That simultaneity is what makes it a
1:54:54
Speaker 1: candidate for for the physical basis of unified experience. But
1:55:00
Speaker 1: critics of SEMI raised an immediate objection. A field that
1:55:05
Speaker 1: is everywhere is a field that is weak. Could the
1:55:08
Speaker 1: brain's endogenous electromagnetic field actually do anything to the neurons
1:55:14
Speaker 1: it passes through, or does it simply wash through tissue
1:55:19
Speaker 1: without any meaningful interaction? The answer came not from theory,
1:55:25
Speaker 1: but for measurement. A 2019 paper by Anastasio and colleagues
1:55:30
Speaker 1: in Nature Neuroscience demonstrated that weak electric fields of exactly
1:55:36
Speaker 1: the kind generated by normal neural activity can influence the
1:55:41
Speaker 1: timing of action potentials in neighboring neurons through what is
1:55:45
Speaker 1: called a faptic coupling, a coupling that requires no synapse,
1:55:51
Speaker 1: no neurotransmitter, no physical contact between cells, the field itself
1:55:57
Speaker 1: reaches through the tissue and nudges the electrical threshold of
1:56:02
Speaker 1: nearby neurons with enough force to shift their firing by
1:56:07
Speaker 1: measurable fractions of a millisecond. The field is not a passenger.
1:56:14
Speaker 1: It has a hand on the wheel. And then the
1:56:18
Speaker 1: data got stranger. A 2022 paper in Cell Reports by
1:56:23
Speaker 1: Hahn and colleagues showed that the brain's endogenous electromagnetic fields
1:56:29
Speaker 1: carry structured information, not noise, structured information. In the experiments,
1:56:36
Speaker 1: the field's patterns predicted the behavioral choices of the animal
1:56:40
Speaker 1: before the neurons generating that information had finished transmitting it
1:56:45
Speaker 1: through synaptic pathways. The field was ahead of the wiring,
1:56:50
Speaker 1: Something in the field's organization was reflecting a decision that
1:56:54
Speaker 1: the classical network had not yet finished computing. That finding
1:57:00
Speaker 1: does not prove semi. But it is the kind of
1:57:04
Speaker 1: result that makes a theory stop sounding like philosophy and
1:57:09
Speaker 1: start sounding like a research program. McFadden updated his theory
1:57:14
Speaker 1: in a 2023 paper titled responding directly to the advances
1:57:19
Speaker 1: in quantum biology that had accumulated since his original proposal.
1:57:25
Speaker 1: And here is where the threads of this entire night
1:57:28
Speaker 1: begin to pull toward each other. In the 2023 update,
1:57:33
Speaker 1: McFadden proposed that microtubule quantum coherence and the brain's electromagnetic
1:57:39
Speaker 1: field are coupled processes. The quantum coherence states in tubulin lattices,
1:57:46
Speaker 1: the oscillations measured in Surrey at 310 Kelvin, the tryptophan
1:57:53
Speaker 1: networks that persist in superposition for hundreds of femtoseconds, are
1:57:58
Speaker 1: not isolated from the larger electromagnetic environment of the brain.
1:58:04
Speaker 1: When those quantum states collapse, when objective reduction in the
1:58:08
Speaker 1: Penrose sense or simple decoherence in the conventional sense brings
1:58:14
Speaker 1: a superposition to a definite outcome, the collapse event injects
1:58:20
Speaker 1: a structured signal into the surrounding electromagnetic field at timescales
1:58:26
Speaker 1: consistent with with the predictions of orchestrated objective reduction. If
1:58:32
Speaker 1: that coupling is real, then the brain is doing something
1:58:36
Speaker 1: no human technology has yet achieved. It is using quantum
1:58:40
Speaker 1: mechanical events at the nanometer scale of protein lattices to
1:58:45
Speaker 1: write structured information into a macroscopic electromagnetic field that spans
1:58:51
Speaker 1: the entire volume of the organ. The quantum computation in
1:58:56
Speaker 1: the microtubule is not the end of the process. It
1:59:00
Speaker 1: is the beginning. The classical field receives the output of
1:59:04
Speaker 1: the quantum process and broadcasts it through every cell in
1:59:09
Speaker 1: the brain simultaneously, binding a billion separate neural events into
1:59:15
Speaker 1: one felt moment at the speed of light. The brain's
1:59:19
Speaker 1: electromagnetic field is not an echo of consciousness. It may
1:59:24
Speaker 1: be its body. And if quantum collapses in microtubules are
1:59:29
Speaker 1: writing into that field, then awareness is not computed in
1:59:34
Speaker 1: any place you can point to, but is woven through
1:59:37
Speaker 1: the whole volume of your head, present everywhere the field
1:59:41
Speaker 1: is present, instantaneous across all of it, at the speed
1:59:45
Speaker 1: of light. One small thread remains loose. If the field
1:59:51
Speaker 1: is the substrate of experience... and quantum collapse writes into
1:59:55
Speaker 1: the field, then the question of what sets the geometry
1:59:59
Speaker 1: of that collapse, what determines which Planck scale structure produces
2:00:06
Speaker 1: which felt quality, is the question that neither Semi nor
2:00:10
Speaker 1: Orch or has yet answered in a form that experiment
2:00:15
Speaker 1: can reach. We are ready now to hold everything together,
2:00:21
Speaker 1: the olive oil correlation and the xenon that erases you,
2:00:26
Speaker 1: the seven-nanometer tube vibrating at terahertz frequencies, the green bacterium
2:00:32
Speaker 1: moving energy without a wasted step, the robin crossing a
2:00:37
Speaker 1: continent on the spin of one electron, the oscillation on
2:00:41
Speaker 1: the screen in Surrey, the mathematician's incompleteness theorem, the decoherence
2:00:48
Speaker 1: time that the protein lattice overturned, the taxol rat taking
2:00:52
Speaker 1: longer to go under, the philosopher's silence in Tucson, and
2:00:56
Speaker 1: this field that binds them all and ask what the
2:00:59
Speaker 1: answer actually is. Charles Overton sat with his bottles of
2:01:04
Speaker 1: olive oil in 1901 and noticed that 19 unrelated molecules,
2:01:12
Speaker 1: a noble gas, a laughing gas, an ether, a dozen
2:01:17
Speaker 1: others with almost nothing in common, all dissolved into lipid
2:01:22
Speaker 1: at precisely the rate they dissolved a mind. That correlation,
2:01:28
Speaker 1: sitting quietly in the literature for a century, was the
2:01:32
Speaker 1: first suggestion that whatever consciousness is, it lives somewhere inside
2:01:37
Speaker 1: the fatty membrane of a cell, somewhere chemistry shades into physics.
2:01:44
Speaker 1: Inside that cell, inside every neuron firing right now, As
2:01:48
Speaker 1: you read this towards sleep, there is a 7-nanometer hollow
2:01:53
Speaker 1: tube of tubulin protein, and it is not scaffolding. It
2:01:58
Speaker 1: is vibrating at terahertz frequencies. Its tryptophan residues are spaced
2:02:04
Speaker 1: at intervals of 1.2 nanometers in a geometry that matches
2:02:09
Speaker 1: the architecture of a quantum error correcting code. It has
2:02:14
Speaker 1: crystalline long-range order stretching for micrometers. The numbers that describe
2:02:20
Speaker 1: it are not the numbers of passive structure. They are
2:02:24
Speaker 1: the numbers of computation. The idea that warm, wet matter
2:02:29
Speaker 1: cannot compute quantum mechanically was demolished not in a brain lab,
2:02:35
Speaker 1: but in a garden by a green sulfur bacterium that
2:02:39
Speaker 1: has been moving photon energy from its antenna complex to
2:02:43
Speaker 1: its reaction center in essentially zero wasted steps. for three
2:02:49
Speaker 1: billion years. Graham Fleming watched quantum beating in his spectroscopy
2:02:54
Speaker 1: data and understood that biology had been running a quantum
2:02:59
Speaker 1: algorithm since before animals existed. The protein scaffold around the
2:03:05
Speaker 1: pigment molecules was not destroying coherence. It was sustaining it,
2:03:11
Speaker 1: tuned to the task by selection pressure across geological time.
2:03:18
Speaker 1: The warm, wet objection died that day, though it took
2:03:21
Speaker 1: years for the news to travel. The robin already knew.
2:03:27
Speaker 1: Eighteen grams of bird, crossing from Scandinavia to sub-Saharan Africa,
2:03:34
Speaker 1: guided by the spin state of a single electron in
2:03:37
Speaker 1: the cryptochrome protein of its retina, entangled with the magnetic
2:03:42
Speaker 1: field of the earth at fifty microtesla. Henrik Moritzson built
2:03:48
Speaker 1: wooden huts and wrapped them in metal and removed every
2:03:52
Speaker 1: classical explanation one by one until only the quantum one remained.
2:03:58
Speaker 1: The radical pair survives for a microsecond in a warm
2:04:02
Speaker 1: biological protein. That is not a small fact. That is
2:04:08
Speaker 1: proof of concept for every skeptic who said living matter
2:04:12
Speaker 1: and quantum entanglement cannot share a sentence, and then the
2:04:16
Speaker 1: oscillation appeared on the screen in Surrey at 310 Kelvin,
2:04:22
Speaker 1: which is the temperature of your body right now. The
2:04:26
Speaker 1: quantum coherence signal in tubulin, predicted for 20 years, dismissed
2:04:32
Speaker 1: for 20 years, measured in the 2022 paper with two-dimensional
2:04:38
Speaker 1: electronic spectroscopy, showing coherence times in the range of hundreds
2:04:43
Speaker 1: of femtoseconds, comparable to photosynthetic systems arising in the same
2:04:49
Speaker 1: protein that lines the interior of every neuron in a
2:04:53
Speaker 1: human brain. John Joe McFadden described the moment the field
2:04:59
Speaker 1: stopped being fringe, the data had arrived. Roger Penrose, at
2:05:05
Speaker 1: his desk in Oxford in 1989, had already written the
2:05:10
Speaker 1: argument that made the data necessary. Human mathematicians can see
2:05:15
Speaker 1: the truth of statements no algorithm can prove. That is
2:05:20
Speaker 1: not a poetic claim. It is a consequence of Gödel' s
2:05:24
Speaker 1: incompleteness theorem applied to the question of what minds do
2:05:30
Speaker 1: that machines cannot. Penrose proposed that the missing physics was
2:05:35
Speaker 1: quantum gravity. that consciousness is not a byproduct of computation,
2:05:42
Speaker 1: but is the physical event of space-time geometry collapsing a
2:05:47
Speaker 1: quantum superposition in a biologically tuned way, and that this
2:05:53
Speaker 1: process is intrinsically experiential rather than merely informational. Max Tegmark
2:06:01
Speaker 1: sat down in 2000 and calculated that that the decoherence
2:06:06
Speaker 1: time for a quantum superposition in a neuron was 10
2:06:10
Speaker 1: to the power of negative 13 seconds, which is 13
2:06:16
Speaker 1: orders of magnitude too short to matter. He was calculating
2:06:21
Speaker 1: the right physics in the wrong geometry. A quantum system
2:06:25
Speaker 1: sitting in water decoheres in femtoseconds. A quantum system embedded
2:06:31
Speaker 1: in a crystalline protein lattice decoheres with topological protection decoheres
2:06:37
Speaker 1: on a time scale that may reach tens to hundreds
2:06:40
Speaker 1: of milliseconds, which is the time scale of the gamma
2:06:44
Speaker 1: oscillations that accompany conscious awareness. The calculation was correct. The
2:06:51
Speaker 1: assumption beneath it was not. Then the Taxol rat took
2:06:56
Speaker 1: 23% longer to go under. Stuart Hameroff waited 27 years
2:07:03
Speaker 1: for that data point. The drug that stiffens microtubules, that
2:07:08
Speaker 1: locks the tubulin lattice in the polymerized state, made the
2:07:13
Speaker 1: brain more resistant to the anesthetic that erases you in
2:07:17
Speaker 1: a dose-dependent curve that looked exactly like a genuine pharmacological mechanism.
2:07:25
Speaker 1: One study in rats is not a revolution, but a
2:07:29
Speaker 1: theory that waits 27 years and then predicts a new
2:07:34
Speaker 1: result correctly has earned the right to be taken seriously.
2:07:40
Speaker 1: David Chalmers stood up in Tucson in 1995 and asked
2:07:45
Speaker 1: why any of this feels like anything at all. He
2:07:49
Speaker 1: called it the hard problem, and the silence that followed
2:07:54
Speaker 1: was the sound of neuroscience realizing it had no answer.
2:07:58
Speaker 1: Classical computation offers no reason why a system processing information
2:08:04
Speaker 1: should feel, from the inside, like anything rather than nothing.
2:08:10
Speaker 1: Quantum collapse, if it is intrinsically experiential as Penrose proposed,
2:08:16
Speaker 1: at least offers a physical process that is more than
2:08:19
Speaker 1: information moving in the dark. And the brain's electromagnetic field,
2:08:25
Speaker 1: spreading through tissue at the speed of light, weaving the
2:08:29
Speaker 1: output of a billion quantum collapses in microtubules into one
2:08:34
Speaker 1: unified felt moment, is at least the shape of an
2:08:37
Speaker 1: answer to the binding question that classical neuroscience has never solved.
2:08:43
Speaker 1: So here is where the evidence points. Not to certainty,
2:08:47
Speaker 1: but to a direction. The brain is not a classical
2:08:51
Speaker 1: computer running a program that happens to produce experience as
2:08:56
Speaker 1: a side effect. The evidence against that picture has been
2:09:00
Speaker 1: accumulating for decades and it is now heavy. The brain
2:09:06
Speaker 1: is also not a simple quantum device in the way
2:09:09
Speaker 1: a superconducting qubit is a quantum device, fragile and cold
2:09:15
Speaker 1: and isolated. It is something biology invented. a system that
2:09:21
Speaker 1: uses the structure of its proteins to protect quantum coherence
2:09:26
Speaker 1: from thermal noise. That converts quantum mechanical events at the
2:09:31
Speaker 1: nanometer scale into macroscopic electromagnetic field patterns, and that has
2:09:38
Speaker 1: been refined by selection for long enough that the words
2:09:43
Speaker 1: accidental and unoptimized no longer apply. Whether that quantum biological
2:09:49
Speaker 1: system is the origin of your experience, whether the collapse
2:09:53
Speaker 1: of a tubulin superposition at the Planck scale is the
2:09:57
Speaker 1: physical event that corresponds to a moment of feeling, whether
2:10:01
Speaker 1: the hard problem dissolves into physics or simply moves one
2:10:05
Speaker 1: level deeper into it, that is not a question this
2:10:08
Speaker 1: evidence can yet answer. The experiments are pointing somewhere specific.
2:10:15
Speaker 1: they are not yet pointing all the way. What you
2:10:19
Speaker 1: can hold, quietly, at the edge of sleep, is this.
2:10:25
Speaker 1: The same universe that built quantum coherence into the photosynthetic
2:10:31
Speaker 1: bacterium and the radical pair in the robin's eye also
2:10:37
Speaker 1: built microtubule lattices into every neuron behind your eyes. The
2:10:43
Speaker 1: same selection pressure that tuned protein geometry to preserve quantum
2:10:48
Speaker 1: states in a leaf may have tuned protein geometry to
2:10:52
Speaker 1: preserve quantum states in a thought. The measurement in Surrey
2:10:58
Speaker 1: at body temperature was not a surprise to biology. It
2:11:03
Speaker 1: may have been the most ancient trick in the living world, repurposed, scaled.
2:11:10
Speaker 1: orchestrated into the organ that now asks whether it is
2:11:15
Speaker 1: doing what it is clearly doing. You are a warm,
2:11:19
Speaker 1: wet system that should not, by the first estimates, be
2:11:23
Speaker 1: able to sustain quantum coherence for long enough to think.
2:11:28
Speaker 1: And yet here you are, thinking and feeling the thinking,
2:11:33
Speaker 1: and noticing the feeling of both, in the dark, at
2:11:37
Speaker 1: the edge of sleep. where the quantum and the classical
2:11:41
Speaker 1: blur together in the way that waking and dreaming blur together,
2:11:46
Speaker 1: and the boundary between them is not a wall but
2:11:49
Speaker 1: a gradient, and no one on either side of that
2:11:52
Speaker 1: gradient has yet explained why there is a someone on
2:11:57
Speaker 1: either side at all. That question is yours to carry.
2:12:03
Speaker 1: The experiments will continue, the rats will be replicated, the
2:12:08
Speaker 1: spectroscopy will be refined, the field theory will be tested,
2:12:14
Speaker 1: and one day, perhaps, the darkness will answer. Until then,
2:12:20
Speaker 1: the darkness knows what it is, even if we do not.
2:12:27
Speaker 1: Good night.