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Can We Ever Truly Understand Reality? · The Last Observer: Science and Beyond

• 0:00
  Speaker 1: I want you to start by just, you know, imagining
• 0:02
  Speaker 1: for a moment the sheer, breathtaking precision of modern scientific achievement.
• 0:07
  Speaker 2: Oh, it's staggering when you actually step back.
• 0:09
  Speaker 1: And look at it, right, I mean truly sit back
• 0:12
  Speaker 1: and think about what we have managed to figure out
• 0:15
  Speaker 1: as a species. It puts everything in perspective. We can
• 0:18
  Speaker 1: predict planetary orbits with the kind of clockwork reliability that
• 0:23
  Speaker 1: would have seemed like pure magic just a few centuries
• 0:26
  Speaker 1: Agoure magic.
• 0:27
  Speaker 2: Yeah, because before that, the sky was just this chaotic,
• 0:30
  Speaker 2: unpredictable mystery exactly.
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  Speaker 1: And all of that clarity is thanks to Isaac Newton
• 0:36
  Speaker 1: just sitting down looking at how things fall and deciding
• 0:39
  Speaker 1: to write the mathematical laws of gravity. And from there
• 0:42
  Speaker 1: we figured out how to unify electricity and magnetism with
• 0:45
  Speaker 1: James Clerk Maxwell's.
• 0:46
  Speaker 2: Equations, which was in the eighteen hundreds, Yeah.
• 0:49
  Speaker 1: Right, the eighteen hundreds, which essentially handed us the blueprints
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  Speaker 1: for the entire modern technological world. Like every screen you
• 0:55
  Speaker 1: look at, every radio wave carrying this very conversation to
• 0:58
  Speaker 1: your ears, it all stems from those specific equations.
• 1:01
  Speaker 2: It's the foundation of everything we use today.
• 1:04
  Speaker 1: It really is and then we've mapped out the fabric
• 1:06
  Speaker 1: of space, time and gravity with Albert Einstein, and if
• 1:10
  Speaker 1: we zoom all the way in, we can actually predict
• 1:13
  Speaker 1: the magnetic moment of an electron to more than ten
• 1:16
  Speaker 1: decimal places using quantum field theory.
• 1:18
  Speaker 2: Ten decimal places, I mean, just think about the level
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  Speaker 2: of certainty that implies.
• 1:22
  Speaker 1: It's insane to more than ten decimal places. We have
• 1:25
  Speaker 1: the standard model of particle physics and the LAMBD to
• 1:30
  Speaker 1: CIDM model of cosmology, which is our current working blueprint
• 1:33
  Speaker 1: of the universe.
• 1:34
  Speaker 2: Yeah, those two frameworks do the heavy lifting for modern physics.
• 1:37
  Speaker 1: They explain almost everything we see, from the faint freezing
• 1:41
  Speaker 1: echoes of the cosmic microwave background radiation left over from
• 1:44
  Speaker 1: the Big Bang to the exact specific way heavy elements
• 1:47
  Speaker 1: like iron and gold were forged in the collapsing fires
• 1:50
  Speaker 1: of dying stars.
• 1:51
  Speaker 2: It really does feel, quite frankly, like we hold a
• 1:54
  Speaker 2: master key to reality itself.
• 1:55
  Speaker 1: That's exactly it, a master key, and it.
• 1:58
  Speaker 2: Is arguably the greatest triumph of the human intellect. When
• 2:02
  Speaker 2: you look at the track record of empirical science, you know,
• 2:06
  Speaker 2: the progression from observing apples falling from trees to detecting
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  Speaker 2: invisible gravitational waves rolling through space time from colliding black
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  Speaker 2: holes billions of light years.
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  Speaker 1: Away, which is still hard to wrap my head around.
• 2:18
  Speaker 2: I know it was wild, but there is this undeniable,
• 2:22
  Speaker 2: overwhelming momentum to it all. It builds this expectation in
• 2:25
  Speaker 2: our culture. It's an almost subconscious assumption that we hold
• 2:29
  Speaker 2: that it is only a matter of time before we
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  Speaker 2: figure literally everything out, right.
• 2:34
  Speaker 1: We just assume we'll get there eventually.
• 2:35
  Speaker 2: Yeah. We tend to view our current ignorance as just
• 2:37
  Speaker 2: a temporary gap in our data. It's a problem that
• 2:40
  Speaker 2: will inevitably be solved by you know, launching a bigger
• 2:43
  Speaker 2: telescope into orbit, or building a more powerful particle accelerator
• 2:47
  Speaker 2: beneath the Swiss Alps, or just programming a faster supercomputer.
• 2:52
  Speaker 1: We assume the universe is just a big puzzle and
• 2:54
  Speaker 1: we just haven't found all the edge pieces yet exactly.
• 2:57
  Speaker 2: That's the prevailing thought, right.
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  Speaker 1: That it's just a matter of leveling up our technology,
• 3:01
  Speaker 1: like we just need a better magnifying glass. Yeah, but
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  Speaker 1: here is where the journey really begins today, and here's
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  Speaker 1: where it gets incredibly strange, very strange, because despite all
• 3:12
  Speaker 1: of this astonishing accuracy, despite all the decimals and the
• 3:15
  Speaker 1: massive telescopes, we are slowly waking up to a profound,
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  Speaker 1: unsettling realization science might actually never explain.
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  Speaker 2: Everything, and not for a lack of trying.
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  Speaker 1: Exactly, not because we are lazy, or because society will
• 3:31
  Speaker 1: run out of funding, or because we just need another
• 3:33
  Speaker 1: thousand years to invent better gadgets. We are talking about fundamental,
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  Speaker 1: hard coded limits that are woven into the very fabric
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  Speaker 1: of mathematics, the physical laws of nature, and the architecture
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  Speaker 1: of the human mind itself.
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  Speaker 2: That's the crucial distinction here. What we are confronting now
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  Speaker 2: is not a lack of effort. We are running face
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  Speaker 2: first into the structural boundaries.
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  Speaker 1: Of reality, like hitting a brick wall.
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  Speaker 2: Yeah, exactly. We are discovering that the universe comes with
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  Speaker 2: its own intrinsic Do not enter sciences as if reality
• 4:01
  Speaker 2: has a maximum resolution and once you hit it, there
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  Speaker 2: is simply no more information to extract.
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  Speaker 1: So what does this actually mean for us for our
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  Speaker 1: understanding of our place in the cosmos? Today? We are
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  Speaker 1: taking you right to the absolute edge of human knowledge.
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  Speaker 1: We are going to explore the uncrossable boundaries of reality.
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  Speaker 2: It's a bit of a dizzying trip, it really is.
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  Speaker 1: We'll look at the mind bending paradoxes hidden inside pure mathematics.
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  Speaker 1: We'll travel to the unreachable dark horizons of did space,
• 4:31
  Speaker 1: and finally we will look inward to the unyielding biological
• 4:34
  Speaker 1: limits of your own brain.
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  Speaker 2: We have to look at the observer too.
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  Speaker 1: Yeah. Right, It's like we've been spending the last few
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  Speaker 1: centuries drawing the most incredibly detailed map of a vast island.
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  Speaker 1: We've been zooming in so closely we can see the
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  Speaker 1: microscopic veins on a single leaf, a beautiful map. But
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  Speaker 1: suddenly we've walked right up to the shoreline, and it
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  Speaker 1: doesn't matter how good our map making tools are or
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  Speaker 1: how sharp our pencils are, the ocean ahead simply cannot
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  Speaker 1: be drawn on the paper we have. The map.
• 5:00
  Speaker 2: Analogy captures the situation beautifully, because if we want to
• 5:04
  Speaker 2: understand why the physical universe has these edges, these dark
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  Speaker 2: oceans we can't cross, we first have to look at
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  Speaker 2: the fundamental language we use to draw the map in
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  Speaker 2: the first place, which is mathematics.
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  Speaker 1: The ultimate tool.
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  Speaker 2: Mathematics is the absolute bedrock of scientific explanation. It is
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  Speaker 2: how we encode the patterns of the stars, how we
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  Speaker 2: predict the outcomes of chemical reactions. We rely on it completely.
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  Speaker 2: But over the last century we have discovered that mathematics
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  Speaker 2: itself harbours intrinsic inescapable boundaries, the language itself has flaws.
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  Speaker 1: Okay, wait, we need to unpack this carefully because usually
• 5:39
  Speaker 1: when you and I think of math, we think is
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  Speaker 1: something flawless like two plus two is four, a triangle
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  Speaker 1: has three sides.
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  Speaker 2: It feels absolutely yeah, it's.
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  Speaker 1: The one place in the universe where absolute, undehiable truth exists.
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  Speaker 1: How can math have a boundary?
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  Speaker 2: To understand how the boundary was found, we have to
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  Speaker 2: go back to the early twentieth century. Mathematicians at that time,
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  Speaker 2: led by brilliant minds like David Hilbert, had this map massive,
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  Speaker 2: ambitious goal.
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  Speaker 1: What were they trying to do?
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  Speaker 2: They wanted to prove that all of mathematics could be
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  Speaker 2: boiled down to a single, perfect formal system.
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  Speaker 1: Okay, before we go further, what actually is a formal system?
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  Speaker 1: Are there like official rules written down somewhere?
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  Speaker 2: Yeah, think of a formal system just like the rules
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  Speaker 2: of jess Okay, chess you have a board, you have pieces,
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  Speaker 2: and you have a very strict set of rules, which
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  Speaker 2: in math are called axioms, that dictate exactly how those
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  Speaker 2: pieces are allowed to move.
• 6:26
  Speaker 1: So a night moves in an L shape, always exactly.
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  Speaker 2: The mathematicians wanted to find a handful of basic, undeniable
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  Speaker 2: axioms for arithmetic, and from those they believe they could
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  Speaker 2: logically derive every single true mathematical statement in existence.
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  Speaker 1: They wanted an air tight, complete rule book.
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  Speaker 2: Perfectly consistent, where every math problem could eventually be proven
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  Speaker 2: true or false. It was called Hilbert's program.
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  Speaker 1: So they wanted to write the ultimate source code for numbers.
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  Speaker 2: That's exactly what they wanted. But then in nineteen thirty one,
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  Speaker 2: a young mathematician named Kurt Guttle come completely shattered the stream.
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  Speaker 1: Just broke it entirely.
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  Speaker 2: Oh, he demolished it. He published what are now known
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  Speaker 2: as his incompleteness theorems. Godle proved with absolute mathematical certainty
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  Speaker 2: that in any formal system powerful enough to handle basic
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  Speaker 2: addition and multiplication, there will always be true statements that
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  Speaker 2: simply cannot be proven from within that system.
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  Speaker 1: Wait, I'm getting stuck in the terminology here. Yeah, isn't
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  Speaker 1: math just numbers we use to count and measure? How
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  Speaker 1: can a math problem be true but unprovable?
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  Speaker 2: It sounds paradoxical, doesn't it.
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  Speaker 1: It sounds like a complete contradiction. If you can't prove it,
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  Speaker 1: how do you know it's true?
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  Speaker 2: It bends the mind. Absolutely. Let's look at how Godel
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  Speaker 2: actually did it, because the mechanism is pure genius. Think
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  Speaker 2: of a classic logical paradox. If I say to you
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  Speaker 2: this statement is a lie. What happens in your brain?
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  Speaker 1: Well, if the statement is true, then it's a lie.
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  Speaker 1: But if it's a lie, then it's telling the truth.
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  Speaker 1: So it just loops forever.
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  Speaker 2: It breaks logic precisely, it's a short circuit. Found a
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  Speaker 2: way to encode a paradox just like that into pure mathematics.
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  Speaker 2: He invented a system called Godal numbering.
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  Speaker 1: What does that do?
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  Speaker 2: Well, every mathematical symbol, every equation, and every proof is
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  Speaker 2: translated into a unique, specific number. This allowed mathematics to
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  Speaker 2: basically talk about itself. Equations could refer to other equations.
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  Speaker 1: So he turned the rules of math into numbers themselves.
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  Speaker 2: He did, and using this, he constructed an equation that
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  Speaker 2: when you translate it back into English, effectively says this
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  Speaker 2: specific mathematical statement cannot be proven to be true within
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  Speaker 2: this system.
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  Speaker 1: Oh wow, he built a self destruct button inside the math.
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  Speaker 2: That's a great way to put it. Now, let's analyze
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  Speaker 2: the trap he built. If his mathematical statement is false,
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  Speaker 2: that means it can be proven. Okay, following, But if
• 8:45
  Speaker 2: you can prove a false statement, your entire system of
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  Speaker 2: mathematics is broken and inconsistent. You've just proved that one
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  Speaker 2: equals zero, so to keep math from collapsing, the statement
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  Speaker 2: must be true.
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  Speaker 1: But wait, If the statement is true, then what it
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  Speaker 1: says is a f act, and what it says is
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  Speaker 1: that it cannot be proven.
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  Speaker 2: You've got it. It is a mathematical truth that is
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  Speaker 2: fundamentally impossible to prove using the rules of the system.
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  Speaker 2: That is wild and Goodle showed that no matter how
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  Speaker 2: many new rules or axioms you add to your system
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  Speaker 2: to tray and cover up these gaps, your new, bigger
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  Speaker 2: system will just generate brand new, true but unprovable statements, so.
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  Speaker 1: The system can never ever be complete.
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  Speaker 2: Never.
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  Speaker 1: It's as if the universe is an incredibly complex video game,
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  Speaker 1: but it's mathematically impossible for the game to ever fully
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  Speaker 1: process its own source code without completely crashing. It's locked
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  Speaker 1: out of fully understanding itself. The rule book can never
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  Speaker 1: finish writing itself.
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  Speaker 2: And the implications of that don't just stay on chalkboards
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  Speaker 2: in university math departments. Alan Turing, who is widely considered
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  Speaker 2: the father of modern computing, took Goodle's concept and applied
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  Speaker 2: it to physical computation.
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  Speaker 1: This is the nineteen thirties two right, yeah.
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  Speaker 2: Nineteen thirty six. Turing was trying to figure out if
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  Speaker 2: there was a mechanical way to solve mathematic problems. In
• 10:01
  Speaker 2: doing so, he basically conceptualized the general purpose computer. But
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  Speaker 2: he also stumbled into a physical wall called the halting problem.
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  Speaker 1: I've heard of the halting problem, but I've never fully
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  Speaker 1: understood the mechanics of it. What exactly is halting? Does
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  Speaker 1: it just mean a computer freezing up?
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  Speaker 2: Essentially? Yes? Turing asked a very specific practical question. Imagine
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  Speaker 2: you have a computer program, any program in the world, Okay.
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  Speaker 2: Turing wanted to know, is it possible to write a
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  Speaker 2: universal master program that can look at any other program's
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  Speaker 2: code and predict perfectly whether that program will eventually finish?
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  Speaker 2: Its task and halt, or if it will get stuck
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  Speaker 2: in an infinite loop and run forever.
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  Speaker 1: That sounds like a basic debugging tool. When an app
• 10:43
  Speaker 1: on my phone freezes, the operating system eventually realizes it's
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  Speaker 1: stuck and force closes it. Do we already have this?
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  Speaker 2: We have tools that catch specific known errors or use timeouts. Sure,
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  Speaker 2: but a universal, flawless predictor that works purely by analyzing
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  Speaker 2: the logic of the code. Turing proved it's logically impossible
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  Speaker 2: to build it.
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  Speaker 1: How did he prove that?
• 11:03
  Speaker 2: To prove it, He's another brilliant thought experiment, he said.
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  Speaker 2: Let's pretend for a moment you did build this perfect
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  Speaker 2: predictor machine. Let's call it the Oracle.
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  Speaker 1: Okay, I have my magical oracle machine.
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  Speaker 2: You feed a piece of code into the oracle and
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  Speaker 2: it spits out a simple, guaranteed answer. This code will
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  Speaker 2: halt or this code will loop forever.
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  Speaker 1: Sounds useful.
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  Speaker 2: It would be now, Turing says, Let's write a brand new,
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  Speaker 2: highly malicious program. Let's call it the Contrarian.
• 11:28
  Speaker 1: Oh.
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  Speaker 2: The Contrarian is designed to ask the oracle what it
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  Speaker 2: is going to do, and then deliberately do the exact opposite.
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  Speaker 1: I see where this is going. It's the liar paradox
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  Speaker 1: all over again.
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  Speaker 2: It is the contrarian's code says, hey, oracle, if you
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  Speaker 2: predict that I am going to halt, I will trigger
• 11:46
  Speaker 2: an infinite loop. But if you predict I am going
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  Speaker 2: to loop forever, I will immediately halt. Right now, what
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  Speaker 2: happens when you feed the contrarian program into the oracle.
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  Speaker 1: The oracle is totally trapped. If it predicts the contrarian halts,
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  Speaker 1: the contrarian loop loops. If it predicts the contrarian loops,
• 12:01
  Speaker 1: the contrarian halts. So the oracle's perfect prediction is mathematically
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  Speaker 1: guaranteed to be wrong.
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  Speaker 2: Which proves that the perfectly predicting oracle cannot exist. There
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  Speaker 2: is no general algorithmic process that can predict the outcome
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  Speaker 2: of every other process.
• 12:15
  Speaker 1: You just have to wait and see exactly.
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  Speaker 2: You can only know for sure what a complex program
• 12:19
  Speaker 2: will do by actually running it, and if it runs forever, well,
• 12:22
  Speaker 2: you'll be waiting forever to find out.
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  Speaker 1: So even if we had a supercomputer the size of
• 12:26
  Speaker 1: the Milky Way galaxy running with absolute perfection, it could
• 12:31
  Speaker 1: not predict the outcome of every possible computational process.
• 12:34
  Speaker 2: It couldn't.
• 12:35
  Speaker 1: It's a hard limit of what can be calculated.
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  Speaker 2: It is a profound limit. And if we push even
• 12:39
  Speaker 2: deeper into the abstract foundations of math, we hit boundaries
• 12:43
  Speaker 2: regarding the concept of infinity itself, specifically the continuum hypothesis.
• 12:48
  Speaker 1: Okay, infinity, that always gives me a headache? What is
• 12:51
  Speaker 1: the continuum hypothesis?
• 12:53
  Speaker 2: To get there, we have to look at the work
• 12:55
  Speaker 2: of a late nineteenth century mathematician named George Cantor. Cantor
• 13:00
  Speaker 2: Or drove himself to the edge of madness studying infinity.
• 13:04
  Speaker 2: Before him, people just thought infinity was infinity. It's just
• 13:07
  Speaker 2: everything that never ends. But Cantor proved mathematically that there
• 13:10
  Speaker 2: are actually different sizes of infinity.
• 13:13
  Speaker 1: Wait, different sizes.
• 13:14
  Speaker 2: Yes, some infinities are larger than others.
• 13:17
  Speaker 1: How can anything be larger than infinity? That feels like
• 13:20
  Speaker 1: saying something is wetter than water.
• 13:22
  Speaker 2: Let's break it down. Think about integer's whole numbers like one, two, three, four,
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  Speaker 2: going on forever.
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  Speaker 1: Okay, an infinitely large set, right.
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  Speaker 2: But now think about real numbers. Real numbers include the integers,
• 13:34
  Speaker 2: but also every single fraction and decimal in between them.
• 13:37
  Speaker 2: So between the integer one and the integer two. You
• 13:40
  Speaker 2: have one point one, one point one one, one point
• 13:42
  Speaker 2: one one, and so on forever.
• 13:44
  Speaker 1: Right, you could keep adding decimal places infinitely, just between
• 13:47
  Speaker 1: one and two exactly.
• 13:48
  Speaker 2: Cantor used a brilliant technique called the diagonal argument to
• 13:52
  Speaker 2: prove that the infinity of those real numbers is vastly
• 13:55
  Speaker 2: immeasurably larger than the infinity of the whole numbers.
• 13:58
  Speaker 1: Even though they both never end.
• 13:59
  Speaker 2: Even though both sets go on forever, you can never
• 14:02
  Speaker 2: match them up one to one. The real numbers represent
• 14:04
  Speaker 2: a higher order of infinity, which.
• 14:06
  Speaker 1: Is already a lot to wrap your head around. But
• 14:08
  Speaker 1: where does the hypothesis come in.
• 14:10
  Speaker 2: The continuum hypothesis simply asks a question, is there another
• 14:15
  Speaker 2: size of infinity that exists strictly between the smaller infinity
• 14:18
  Speaker 2: of the whole numbers and the larger infinity of the
• 14:21
  Speaker 2: real numbers.
• 14:22
  Speaker 1: Like a middle size infinity?
• 14:23
  Speaker 2: Exactly? Is there a middle one?
• 14:25
  Speaker 1: Okay, So what's the answer? Yes or no?
• 14:26
  Speaker 2: The mind blowing part is that we have proven that
• 14:29
  Speaker 2: the answer is completely undecidable. It is entirely independent of
• 14:33
  Speaker 2: our standard foundation in mathematics, which is called Zumelo francal
• 14:37
  Speaker 2: set theory.
• 14:37
  Speaker 1: Wait, I need you to translate that. What does it
• 14:40
  Speaker 1: mean for a math problem to be independent of the
• 14:42
  Speaker 1: foundation of math.
• 14:43
  Speaker 2: Let's go back to our chess analogy. Zumello Frankel set theory,
• 14:47
  Speaker 2: often just called ZFC, is the rule book for modern math.
• 14:51
  Speaker 2: It's the list of axioms that mathematicians agreed upon in
• 14:54
  Speaker 2: the early twentieth century to serve as the bedrock for
• 14:57
  Speaker 2: all other math.
• 14:58
  Speaker 1: Okay, but the standard rule book.
• 14:59
  Speaker 2: What mathemat titians discovered in the nineteen sixties is that
• 15:02
  Speaker 2: the continuum hypothesis isn't governed by those rules.
• 15:06
  Speaker 1: So the rule book just doesn't have an answer.
• 15:08
  Speaker 2: It's worse than that, the rule book allows you to
• 15:10
  Speaker 2: choose your own answer without breaking the game. Really, yes,
• 15:13
  Speaker 2: you can assume the continuum hypothesis is true and you
• 15:16
  Speaker 2: can build a perfectly logical, consistent system of mathematics from
• 15:19
  Speaker 2: that point forward. Or you can assume it is false
• 15:23
  Speaker 2: and build an equally consistent logical system of.
• 15:26
  Speaker 1: Mathematics and neither breaks math.
• 15:28
  Speaker 2: Neither choice will ever lead to a contradiction within ZFC.
• 15:32
  Speaker 2: It is fundamentally undecidable. Based on the standard rules of
• 15:36
  Speaker 2: math we use to describe the world.
• 15:38
  Speaker 1: So we literally just have to pick a lane and
• 15:39
  Speaker 1: go with it. That feels so arbitrary for something that
• 15:43
  Speaker 1: is supposed to be the objective bedrock of reality.
• 15:45
  Speaker 2: You're hitting on the exact reason why physicists care about this.
• 15:49
  Speaker 2: Science relies on computable, predictive mathematical models. We use math
• 15:55
  Speaker 2: to describe the physical universe, right, But if mathematics itself
• 15:59
  Speaker 2: has these unresolve maupable blind spots. If there are truths
• 16:02
  Speaker 2: we can't prove, programs we can't predict, and infinite sets
• 16:05
  Speaker 2: we can't pin down, then what does that say about
• 16:08
  Speaker 2: our physics?
• 16:09
  Speaker 1: It means the language is incomplete.
• 16:11
  Speaker 2: If the universe contains non computable or non algorithmic processes,
• 16:15
  Speaker 2: our physical theories are always going to be approximations. Godal
• 16:19
  Speaker 2: and Turing didn't just find bugs in our math, they
• 16:21
  Speaker 2: discovered structural features of logic itself.
• 16:24
  Speaker 1: So even if an alien species handed us a perfect
• 16:27
  Speaker 1: mathematical description of reality.
• 16:29
  Speaker 2: It would inevitably contain blind spots.
• 16:31
  Speaker 1: And we actually see this abstract mathematical limitation play out
• 16:35
  Speaker 1: in the messy physical world when we look at chaos theory,
• 16:38
  Speaker 1: don't we Because even when we theoretically have the math
• 16:41
  Speaker 1: figured out. Physical reality completely refuses to be perfectly predicted.
• 16:46
  Speaker 2: Chaos theory is the perfect bridge from the abstract limits
• 16:50
  Speaker 2: of pure math to the practical limits of everyday physics.
• 16:54
  Speaker 2: In classical mechanics, you know, the physics of Newton, everything
• 16:57
  Speaker 2: is supposed to be deterministic, like billie balls. Exactly, if
• 17:01
  Speaker 2: you hit a billiard ball with a certain amount of
• 17:03
  Speaker 2: force at a certain angle, it will bounce in a
• 17:06
  Speaker 2: perfectly predictable.
• 17:07
  Speaker 1: Way, pure cause and effects.
• 17:09
  Speaker 2: And this led to a famous philosophical concept called Laplace's demon,
• 17:13
  Speaker 2: named after the mathematician Pierre Simon la Place.
• 17:16
  Speaker 1: I've heard of this demon.
• 17:17
  Speaker 2: He proposed a thought experiment. Imagine a superintellect, a demon
• 17:22
  Speaker 2: that at one specific moment knows the exact location and
• 17:25
  Speaker 2: momentum of every single atom in the entire universe, and
• 17:29
  Speaker 2: understands all the forces.
• 17:30
  Speaker 1: Acting upon them, So it knows everything right now right.
• 17:33
  Speaker 2: Laplace argued that for such an intellect, nothing would be uncertain.
• 17:37
  Speaker 2: The entire future and the entire past would be perfectly
• 17:41
  Speaker 2: visible to it, like a simple math equation.
• 17:43
  Speaker 1: If you know the starting lineup, you know the final score.
• 17:46
  Speaker 2: That was the dream. But chaos theory dismantled it by
• 17:50
  Speaker 2: showing us that in complex nonlinear systems, microscopic determinism does
• 17:55
  Speaker 2: not equal macroscopic predictability.
• 17:57
  Speaker 1: What's a nonlinear system?
• 17:58
  Speaker 2: A nonlinear system is one where a tiny change in
• 18:02
  Speaker 2: the starting conditions doesn't just produce a tiny change in
• 18:05
  Speaker 2: the outcome, it produces an exponentially massive change in the outcome.
• 18:10
  Speaker 1: Oh, this is the famous butterfly effect, right, That's the
• 18:13
  Speaker 1: one A butterfly flaps its wings in Brazil and the
• 18:16
  Speaker 1: tiny change in air pressure eventually compounds and sets off
• 18:19
  Speaker 1: a tornado in Texas weeks later.
• 18:22
  Speaker 2: That's the classic example, originally formulated by the meteorologist Edward Lorenz.
• 18:26
  Speaker 2: He was running a computer simulation of the weather in
• 18:29
  Speaker 2: the nineteen sixties. He decided to rerun a sequence, but
• 18:32
  Speaker 2: to save time, he started it from the middle.
• 18:34
  Speaker 1: Okay, makes sense.
• 18:36
  Speaker 2: Instead of typing in the full decimal value of a
• 18:38
  Speaker 2: number like zero point five zero six one two seven,
• 18:42
  Speaker 2: he rounded it slightly to two point five zero six.
• 18:45
  Speaker 2: He expected the weather simulation to diverge slightly from his.
• 18:48
  Speaker 1: First run, but it didn't just diverge slightly.
• 18:50
  Speaker 2: No, that microscopic difference compounded, so rapidly that the simulation
• 18:54
  Speaker 2: produced a completely wildly different weather.
• 18:58
  Speaker 1: Pattern just from cutting off a few discs places.
• 19:00
  Speaker 2: Because to predict a chaotic system perfectly, you would need
• 19:03
  Speaker 2: to know the initial conditions with absolutely infinite perfect precision.
• 19:08
  Speaker 2: And as we just discussed with Godal and Turing, our
• 19:11
  Speaker 2: mathematical and computational frameworks simply don't allow for infinite precision
• 19:15
  Speaker 2: handling in the real.
• 19:16
  Speaker 1: World, right the infinite decimals.
• 19:18
  Speaker 2: Think about the three body problem in astronomy. If you
• 19:21
  Speaker 2: have two massive objects like the Earth and the Sun,
• 19:24
  Speaker 2: Newton's laws can predict their orbits forever, but the moment
• 19:27
  Speaker 2: you add a third object like Jupiter, their gravitational pulls
• 19:30
  Speaker 2: on each other become chaotic.
• 19:32
  Speaker 1: The math gets messy.
• 19:33
  Speaker 2: The math tells us exactly how gravity works between them,
• 19:36
  Speaker 2: but it also tells us we can never practically predict
• 19:39
  Speaker 2: their exact positions millions of years from now. Any measurement error,
• 19:44
  Speaker 2: even one ten billionth of a decimal point, will explode
• 19:48
  Speaker 2: over time until your prediction is worse than a wild guess.
• 19:51
  Speaker 1: Wow. So if the mathematical code of reality has these
• 19:56
  Speaker 1: build in logical blind spots, and our macroscopic eva day
• 20:00
  Speaker 1: world is completely tangled up in the unpredictable butterfly wings
• 20:04
  Speaker 1: of chaos. What happens when we go the other way
• 20:07
  Speaker 1: you mean zooming in? Yeah, what happens when we zoom
• 20:09
  Speaker 1: all the way in? Because you'd think if the big
• 20:11
  Speaker 1: things are chaotic, maybe the smallest building blocks are solid
• 20:14
  Speaker 1: and reliable. But when we look at the physical pixels
• 20:17
  Speaker 1: of the universe, we find that at the smallest level,
• 20:20
  Speaker 1: reality doesn't just get a little blurry. It fundamentally refuses
• 20:23
  Speaker 1: to be pinned down. Welcome to the deeply uncomfortable world
• 20:27
  Speaker 1: of quantum mechanics.
• 20:28
  Speaker 2: Calling it uncomfortable as an understatement, quantum mechanics is arguably
• 20:32
  Speaker 2: the most successful, rigorously tested scientific theory in human history.
• 20:36
  Speaker 1: Really more than relativity, Oh absolutely.
• 20:39
  Speaker 2: It underpins almost our entire modern technological world. The semiconductors
• 20:45
  Speaker 2: and the device you're using right now to listen to this,
• 20:47
  Speaker 2: the principles of modern chemistry, lasers, MRI, machines, and hospitals.
• 20:53
  Speaker 2: None of these exist without an incredibly deep mathematical mastery
• 20:57
  Speaker 2: of quantum mechanics. That we know how to use it,
• 20:59
  Speaker 2: We know exactly how to use it. But what the
• 21:02
  Speaker 2: theory actually says about the fundamental nature of reality is
• 21:06
  Speaker 2: deeply unsettling because it introduces irreducible, fundamental randomness into the universe.
• 21:12
  Speaker 2: It completely kills Laplace's dream of a perfectly predictable clockwork cosmos.
• 21:18
  Speaker 1: Let's start with the most famous roadblock down there, Heisenberg's
• 21:21
  Speaker 1: uncertainty principle, because I think people often hear the word
• 21:24
  Speaker 1: uncertainty and they think, oh, our electron microscopes just aren't
• 21:27
  Speaker 1: good enough yet, if we just build a better tool,
• 21:29
  Speaker 1: we'll be certain. Right.
• 21:30
  Speaker 2: That's a very common assumption.
• 21:31
  Speaker 1: But that's not what Erner Heisenberg was saying at all,
• 21:33
  Speaker 1: is it.
• 21:34
  Speaker 2: No, you are absolutely right. Heisenberg's principle states that you
• 21:37
  Speaker 2: cannot simultaneously know both the exact position and the exact
• 21:40
  Speaker 2: momentum of a quantum particle like an electron at the
• 21:44
  Speaker 2: same time at the same time. And it is crucial
• 21:46
  Speaker 2: to emphasize that this is not a limitation of our
• 21:49
  Speaker 2: measuring tools. It is not clumsiness on the part of
• 21:51
  Speaker 2: the scientist. So what is it the universe physically forbids
• 21:55
  Speaker 2: those two properties from having perfectly defined values at the
• 21:58
  Speaker 2: exact same time.
• 21:59
  Speaker 1: I need a way to visualize this, because if I
• 22:01
  Speaker 1: am driving down the highway. My car has a very
• 22:04
  Speaker 1: specific location, say mile mark or forty two, and a
• 22:07
  Speaker 1: very specific momentum sixty five miles per hour. Why doesn't
• 22:12
  Speaker 1: an electron.
• 22:13
  Speaker 2: To understand why, you have to abandon the idea that
• 22:16
  Speaker 2: an electron is a tiny, hard, little billiard ball. At
• 22:19
  Speaker 2: the quantum level, matter exhibits wave particle duality. Particles act
• 22:24
  Speaker 2: like waves, Okay, waves. Imagine a wave rolling across the ocean.
• 22:27
  Speaker 2: If I ask you what is the exact precise location
• 22:31
  Speaker 2: of that wave, you'd struggle to answer, because the wave
• 22:33
  Speaker 2: is spread out over a wide area.
• 22:35
  Speaker 1: Right, it doesn't have a single coordinate.
• 22:36
  Speaker 2: But if I ask you what is the wavelength, which
• 22:39
  Speaker 2: translates to momentum and physics of that wave, you can
• 22:42
  Speaker 2: measure the distance between the crests very easily.
• 22:45
  Speaker 1: Okay, So a spread out wave has a clear momentum
• 22:47
  Speaker 1: but a fuzzy location exactly.
• 22:49
  Speaker 2: Now, imagine you want to give that wave a precise location.
• 22:52
  Speaker 2: You try to squeeze it down into a single, tiny,
• 22:55
  Speaker 2: sharp spike of water.
• 22:56
  Speaker 1: Okay, I'm squeezing it.
• 22:58
  Speaker 2: You now know exactly where it is. But in squeezing
• 23:00
  Speaker 2: it into a spike, you destroyed the repeating pattern of
• 23:03
  Speaker 2: crests and troughs. It no longer has a wavelength. The
• 23:08
  Speaker 2: more precisely you pin down its position, the more wildly
• 23:11
  Speaker 2: undefined its momentum becomes. It is baked into the mathematical
• 23:15
  Speaker 2: nature of what a wave is.
• 23:17
  Speaker 1: So it's not that the electron is hiding its location
• 23:20
  Speaker 1: in steed from us. It's that the electron literally doesn't
• 23:24
  Speaker 1: possess a precise location and speed at the same time.
• 23:27
  Speaker 1: The concept of it having both doesn't exist in nature.
• 23:30
  Speaker 2: That is the heart of it, and this realization leads
• 23:32
  Speaker 2: us directly to the core mathematical tool physicists used to
• 23:36
  Speaker 2: describe the quantum world, the Schrodinger equation. Schrodinger, like the cat,
• 23:40
  Speaker 2: same guy Erwin Schrodinger created an equation that is mathematically
• 23:44
  Speaker 2: beautiful and surprisingly, it evolves completely deterministically. If you have
• 23:48
  Speaker 2: an isolated quantum system, the Schrodinger equation tells you exactly
• 23:51
  Speaker 2: how its wave function changes over time.
• 23:53
  Speaker 1: Okay, we need to define wave function. What is that Physically?
• 23:57
  Speaker 2: A wave function is a mathematical description of all the
• 24:00
  Speaker 2: possible states a quantum particle could be in. Let's say
• 24:03
  Speaker 2: you fire an electron at a wall with two tiny slits.
• 24:06
  Speaker 1: In it, the famous double slit experience.
• 24:09
  Speaker 2: The wave function describes the probability of the electron going
• 24:12
  Speaker 2: through the left slit and the probability of it going
• 24:15
  Speaker 2: through the right slit. Before you measure it, the electron
• 24:18
  Speaker 2: isn't in one place or the other. It exists in
• 24:20
  Speaker 2: a superposition a smear of probabilities, a smear, and the
• 24:25
  Speaker 2: Schrodinger equation tells us exactly how that smear of probability
• 24:29
  Speaker 2: is ripples and moves through space.
• 24:31
  Speaker 1: Right, the wave function is just a list of changing possibilities.
• 24:35
  Speaker 1: But obviously, when I look at the wall, I don't
• 24:37
  Speaker 1: see a smear of probabilities. I see a single physical
• 24:41
  Speaker 1: mark where the electron actually hit. So how do we
• 24:44
  Speaker 1: get from a mathematical smear to a physical reality?
• 24:47
  Speaker 2: And now you have arrived at the measurement problem, which
• 24:50
  Speaker 2: is perhaps the greatest unresolved mystery in physics.
• 24:53
  Speaker 1: What happens when you measure it?
• 24:54
  Speaker 2: When you actually look at the particle, When a conscious
• 24:57
  Speaker 2: observer or even just a macroscopic measuring device interacts with it,
• 25:02
  Speaker 2: the deterministic evolution of the Shroudinger equation instantly stops. The
• 25:07
  Speaker 2: wave function is said to collapse.
• 25:09
  Speaker 1: It just snaps into reality.
• 25:10
  Speaker 2: Yes, out of all those spread out probabilities, one single
• 25:15
  Speaker 2: definite outcome suddenly materializes.
• 25:18
  Speaker 1: And how does the universe decide which outcome materializes?
• 25:21
  Speaker 2: As far as we can tell, it is completely fundamentally random.
• 25:25
  Speaker 2: The exact outcome that happens is probabilistic.
• 25:27
  Speaker 1: It's like running a cosmic lottery. We know exactly what
• 25:30
  Speaker 1: the odds are. The Shrodinger equation tells us perfectly how
• 25:33
  Speaker 1: many tickets are sold and what the chances are of
• 25:35
  Speaker 1: each number winning, But it is physically impossible to know
• 25:39
  Speaker 1: who holds the winning ticket until the exact moment it
• 25:42
  Speaker 1: is drawn. The universe just reaches into the hat and picks.
• 25:45
  Speaker 2: That's a great way to think about it.
• 25:46
  Speaker 1: So I have to ask you a direct, deeply philosophical
• 25:49
  Speaker 1: question here. If individual quantum events happen without a traditional cause,
• 25:55
  Speaker 1: like if there is absolutely no underlying physical reason radioactive
• 26:00
  Speaker 1: atom decides to decay at this exact millisecond instead of
• 26:04
  Speaker 1: a year from now, does this mean the universe is
• 26:07
  Speaker 1: essentially making things up as it goes along.
• 26:10
  Speaker 2: That question keeps physicists up at night. Does the universe
• 26:13
  Speaker 2: make it up on the fly? Rolling dice in the
• 26:15
  Speaker 2: dark or is there a deeper hidden script we just
• 26:18
  Speaker 2: can't read?
• 26:19
  Speaker 1: What do physicists think?
• 26:20
  Speaker 2: Because the math works perfectly for calculating the odds, but
• 26:24
  Speaker 2: it remains entirely silent on what reality is actually doing
• 26:27
  Speaker 2: behind the scenes to make those odds happen. To deal
• 26:30
  Speaker 2: with this silence, physicists have proposed various interpretations of quantum mechanics.
• 26:34
  Speaker 2: Interpretations not new math, right, These aren't different maths. There
• 26:37
  Speaker 2: are different stories we tell ourselves to try and make
• 26:39
  Speaker 2: sense of the math.
• 26:40
  Speaker 1: Let's go through some of these stories, because I know
• 26:42
  Speaker 1: they get pretty wild.
• 26:43
  Speaker 2: They get incredibly wild. The most famous alternative to true
• 26:46
  Speaker 2: randomness is the many worlds interpretation, originally proposed by Hugh Everett.
• 26:51
  Speaker 1: Many Worlds I've seen the sci fi movies.
• 26:54
  Speaker 2: This interpretation suggests that the wave function never actually collapses at.
• 26:57
  Speaker 1: All, but I only see one elect hit the wall.
• 27:00
  Speaker 2: According to Many Worlds, that's because you are only experiencing
• 27:04
  Speaker 2: one branch of reality. This interpretation posits that every single
• 27:08
  Speaker 2: time a quantum measurement happens, reality itself physically splits the
• 27:14
  Speaker 2: universe branches into multiple, paralleled, non communicating realities.
• 27:18
  Speaker 1: So every possibility happens.
• 27:20
  Speaker 2: Every possible outcome contained in the wave function actually physically happens,
• 27:24
  Speaker 2: just in different universes. So in one universe the atom
• 27:28
  Speaker 2: decays today, and in another parallel universe, an identical version
• 27:32
  Speaker 2: of you watches the atom wait until tomorrow to decay, which.
• 27:36
  Speaker 1: Is mathematically very elegant because you don't have to explain
• 27:38
  Speaker 1: the mysterious collapse, but philosophically it is absolutely insane. You
• 27:42
  Speaker 1: are conjuring an infinite number of completely real, entire universes
• 27:47
  Speaker 1: every single fraction of a millisecond, just to avoid saying
• 27:50
  Speaker 1: the universe rolls dice.
• 27:52
  Speaker 2: It is a massive ontological price to pay just to
• 27:55
  Speaker 2: save determinism.
• 27:56
  Speaker 1: What are the other options?
• 27:57
  Speaker 2: On the other end of the spectrum, you have the
• 27:59
  Speaker 2: Copenhagen interpretation, spearheaded by Nils Bohr and Werner Heisenberg. This
• 28:04
  Speaker 2: is historically the most popular view among working physicists.
• 28:07
  Speaker 1: What's their story?
• 28:08
  Speaker 2: It essentially says, stop worrying about what's happening behind the scenes.
• 28:12
  Speaker 2: The wave function isn't a real physical object. It's just
• 28:16
  Speaker 2: a mathematical tool we use to calculate probabilities. The active
• 28:20
  Speaker 2: measurement simply forces reality to make a.
• 28:23
  Speaker 1: Choice, so they just accept the randomness.
• 28:25
  Speaker 2: Yes, the Copenhagen interpretation accepts fundamental, uncaused randomness as a
• 28:31
  Speaker 2: bedrock feature of nature.
• 28:33
  Speaker 1: That's the shut up and calculate approach. Don't ask what
• 28:35
  Speaker 1: reality is, just use the math to build better lasers.
• 28:39
  Speaker 2: Quite literally, yes, But for physicists who hate randomness and
• 28:43
  Speaker 2: hate infinite universes, there are pilot wave theories like the
• 28:46
  Speaker 2: Debrugli boom theory.
• 28:48
  Speaker 1: How does that one work?
• 28:49
  Speaker 2: This suggests the randomness is just an illusion of our ignorance.
• 28:52
  Speaker 2: They propose that particles do actually have exact positions at
• 28:56
  Speaker 2: all times, and they are guided by invisible pilot waves.
• 28:59
  Speaker 1: That sounds reasonable. Why isn't that the standard?
• 29:01
  Speaker 2: Because to make the math of the pilot wave work,
• 29:04
  Speaker 2: the theory has to be radically non local.
• 29:07
  Speaker 1: What does non local mean?
• 29:09
  Speaker 2: That means every single particle in the universe must be
• 29:12
  Speaker 2: instantly instantaneously connected to the pilot wave of every other particle,
• 29:17
  Speaker 2: regardless of distance. If you wiggle an electron here on Earth,
• 29:21
  Speaker 2: the pilot wave guiding an electron in the Andromeda galaxy
• 29:25
  Speaker 2: has to adjust instantly faster than the speed of light.
• 29:28
  Speaker 1: Which violates Einstein's theory of relativity.
• 29:30
  Speaker 2: It severely strains it. Yes, and finally we have newer,
• 29:35
  Speaker 2: more subjective ideas like cubism, quantum Beaiesianismubism. Cubism argues that
• 29:40
  Speaker 2: the wave function isn't a physical thing out in the world,
• 29:43
  Speaker 2: nor is it a mechanism of multiple universes. It argues,
• 29:47
  Speaker 2: the wave function is merely a mathematical representation of an
• 29:50
  Speaker 2: observer's subjective degree of belief about what they will measure next.
• 29:53
  Speaker 1: So it puts the human at the center.
• 29:55
  Speaker 2: It places the observer's information right at the center of reality.
• 29:59
  Speaker 1: So we have made any worlds, creating infinite realities. Copenhagen
• 30:03
  Speaker 1: accepting uncaused magic, dice, pilot wave breaking, the speed limit
• 30:08
  Speaker 1: of light, and cubism saying it's all just subjective belief.
• 30:12
  Speaker 1: None of these actually resolve the mystery without forcing us
• 30:15
  Speaker 1: to make massive, deeply uncomfortable assumptions about how the universe operates.
• 30:20
  Speaker 2: None of them. And what's truly fascinating is that physicists
• 30:23
  Speaker 2: didn't just sit around debating philosophy. They actually figured out
• 30:26
  Speaker 2: a way to run physical experiments to see if there's
• 30:29
  Speaker 2: some hidden clockwork, some secret variables acting behind the scenes
• 30:32
  Speaker 2: that we just couldn't see, which would prove laplus right
• 30:35
  Speaker 2: after all.
• 30:36
  Speaker 1: Wait, they tested this.
• 30:37
  Speaker 2: In nineteen sixty four, a physicist named John Bell formulated
• 30:40
  Speaker 2: Bell's theorem. He came up with a brilliant mathematical way
• 30:43
  Speaker 2: to test if reality has what are called local hidden variables.
• 30:47
  Speaker 1: Let's break that phrase down. Yeah, local meaning that cause
• 30:50
  Speaker 1: and effect are bound by the speed of light, things
• 30:52
  Speaker 1: only affect their immediate surroundings. And hidden variables meaning secret
• 30:56
  Speaker 1: classical gears making the quantum world turn kind of like
• 30:59
  Speaker 1: the pilot wave idea, without the faster than light weirdness.
• 31:02
  Speaker 2: That's a perfect summary. Bell proposed an experiment using quantum entanglement.
• 31:08
  Speaker 2: Entanglement is a phenomenon where two particles, say two electrons,
• 31:13
  Speaker 2: interact and become deeply linked. Their quantum states merge.
• 31:17
  Speaker 1: Okay, so they're connected.
• 31:18
  Speaker 2: If you measure the spin of one electron and find
• 31:21
  Speaker 2: its pointing up, the other electron will instantly be found
• 31:24
  Speaker 2: pointing down. They always perfectly anti correlate, and no matter
• 31:28
  Speaker 2: how far apart you separate.
• 31:29
  Speaker 1: Them, even if one is on Earth and the other
• 31:31
  Speaker 1: is on Mars.
• 31:32
  Speaker 2: Yes. Now, Einstein hated this. He called it spooky action.
• 31:36
  Speaker 2: At a distance. Einstein believed the electrons must have had
• 31:40
  Speaker 2: a hidden variable.
• 31:41
  Speaker 1: Like they secretly agreed beforehand.
• 31:43
  Speaker 2: He argued, it was like putting a left glove in
• 31:45
  Speaker 2: one box and a right glove in another box and
• 31:47
  Speaker 2: shipping them to Mars and Earth. When you open the
• 31:50
  Speaker 2: Earth box and see a left glove, you instantly know
• 31:52
  Speaker 2: the Mars box has a right glove.
• 31:54
  Speaker 1: That makes total sense.
• 31:55
  Speaker 2: There's no spooky communication. The gloves knew what they were
• 31:58
  Speaker 2: the whole time, were hidden inside them from the start.
• 32:02
  Speaker 1: That is a very logical, classical way to think about it. Okay,
• 32:05
  Speaker 1: so how did Bell prove Einstein wrong?
• 32:07
  Speaker 2: Bell realized that if you measure the spin of these
• 32:09
  Speaker 2: electrons not just purely up or down, but along different
• 32:13
  Speaker 2: randomly chosen angled axes, the math of hidden variables predicts
• 32:17
  Speaker 2: a very specific statistical limit on how often the measurements
• 32:21
  Speaker 2: should match up.
• 32:22
  Speaker 1: A ceiling on the correlation.
• 32:24
  Speaker 2: He created an absolute mathematical ceiling for the gloves theory.
• 32:28
  Speaker 2: If Einstein was right, the correlation could never exceed a
• 32:31
  Speaker 2: certain percentage. But if quantum mechanics was right, and the
• 32:34
  Speaker 2: particles were truly undefined until measured and somehow acting as
• 32:38
  Speaker 2: a single non local system, they would violate Bell's limit
• 32:41
  Speaker 2: and correlate more often.
• 32:43
  Speaker 1: And what happened when we actually ran the experiment.
• 32:45
  Speaker 2: Over the last few decades, culminating in the twenty twenty
• 32:48
  Speaker 2: two Nobel Prize in physics, scientists have run incredibly precise
• 32:52
  Speaker 2: experiments separating entangled particles over massive distances. They have conclusively,
• 32:57
  Speaker 2: definitively violated Bell's limit. Wow, they have ruled out local
• 33:02
  Speaker 2: hidden variables entirely.
• 33:04
  Speaker 1: Meaning Einstein's left and right glove analogy is physically incorrect.
• 33:08
  Speaker 2: It is dead. The results show that reality must be
• 33:11
  Speaker 2: either fundamentally non local, meaning there truly is spooky action
• 33:16
  Speaker 2: at a distance, where an entangled particle here is instantly
• 33:20
  Speaker 2: coordinating with a particle across the galaxy entirely bypassing the
• 33:24
  Speaker 2: speed of light. Or reality is incredibly contextual, meaning the
• 33:29
  Speaker 2: physical properties of a particle literally do not exist in
• 33:31
  Speaker 2: any meaningful way until a measurement is forced upon them.
• 33:35
  Speaker 2: Either way, Laplace's dream of a perfectly predictable, localized clockwork
• 33:40
  Speaker 2: universe is dead and buried.
• 33:42
  Speaker 1: Science can predict the statistical behavior of a crowd of
• 33:45
  Speaker 1: particles flawlessly, but the individual quantum event is fundamentally unknowable
• 33:50
  Speaker 1: before it happens. It lacks a classical cause.
• 33:53
  Speaker 2: It's just inherently fuzzy.
• 33:54
  Speaker 1: And as if quantum randomness wasn't enough of a cage,
• 33:57
  Speaker 1: we are now learning that there might be a hard
• 33:59
  Speaker 1: physic limit to how much information a given volume of
• 34:02
  Speaker 1: space can even hold in the first place.
• 34:04
  Speaker 2: Yes, this brings us to the holographic principle. This is
• 34:07
  Speaker 2: a concept that emerged from the intersection of quantum mechanics,
• 34:10
  Speaker 2: black hole thermal dynamics, and string theory.
• 34:12
  Speaker 1: Black holes always make things weirder.
• 34:14
  Speaker 2: A physicist named Jacob Beegenstein discovered something astonishing about black holes.
• 34:19
  Speaker 2: He realized that the amount of information the entropy that
• 34:23
  Speaker 2: a black hole can contain is not proportional to its
• 34:26
  Speaker 2: three dimensional volume as you would intuitively expect.
• 34:29
  Speaker 1: What is there proportional too?
• 34:30
  Speaker 2: It is proportional only to the two dimensional surface area
• 34:34
  Speaker 2: of its event horizon.
• 34:35
  Speaker 1: Wait, if I pack more stuff into a box, the
• 34:37
  Speaker 1: amount of stuff at holds depends on the volume of
• 34:39
  Speaker 1: the box. How can it only depend on the surface area?
• 34:42
  Speaker 2: That is exactly why it was so shocking Bigenstein and
• 34:46
  Speaker 2: later Gerard Hoofed and Leonard Suskin generalize this into the
• 34:49
  Speaker 2: holographic principle. It posits that all the information contained within
• 34:53
  Speaker 2: any three dimensional volume of space, your living room, the Earth,
• 34:57
  Speaker 2: the entire universe can actually be fully described by a
• 35:01
  Speaker 2: mathematically equivalent theory operating purely on the two dimensional surface
• 35:05
  Speaker 2: boundary that encloses that space.
• 35:07
  Speaker 1: Like a literal hologram. Yeah, the three D image of
• 35:10
  Speaker 1: a princess I see floating in the air is just
• 35:12
  Speaker 1: a projection encoded on a flat two D piece.
• 35:14
  Speaker 2: Of plastic precisely the right analogy. And while that mathematical
• 35:18
  Speaker 2: trick solves some incredibly deep problems in theoretical physics, it
• 35:22
  Speaker 2: implies a profound hard limit on reality itself. Also, it
• 35:26
  Speaker 2: gives us the Baekenstein bound, a strict limit on the
• 35:30
  Speaker 2: maximum amount of information you can pack into a region
• 35:32
  Speaker 2: of space before it collapses into a black hole. If
• 35:36
  Speaker 2: the maximum amount of information in a space is bounded
• 35:39
  Speaker 2: by its surface area rather than its volume, it means
• 35:42
  Speaker 2: reality is far less dense with information than we thought.
• 35:45
  Speaker 1: It's like looking at a screen too closely and seeing
• 35:47
  Speaker 1: the pixels.
• 35:47
  Speaker 2: Yes, it means we may never be able to access
• 35:50
  Speaker 2: a true, independent interior description of space time, the ultimate
• 35:54
  Speaker 2: highest resolution pixel of reality might be forever locked on
• 35:57
  Speaker 2: a two D boundary, and the three D world world
• 36:00
  Speaker 2: we experience is just a holographic projection of that data.
• 36:03
  Speaker 1: So we can't perfectly zoom in on the quantum realm.
• 36:05
  Speaker 1: If we try, reality fuzzes out into probabilities, spooky entanglement,
• 36:10
  Speaker 1: and two D holograms. The microscopic map just dissolved.
• 36:14
  Speaker 2: It dissolves completely.
• 36:15
  Speaker 1: But surely if we go the other way, if we
• 36:18
  Speaker 1: zoom out to the macroscopic world of stars and galaxies,
• 36:22
  Speaker 1: things make sense, right, we have big telescopes. But what
• 36:24
  Speaker 1: we find when we zoom out is that the cosmos
• 36:27
  Speaker 1: itself has built physical cages around us. We are trapped
• 36:30
  Speaker 1: in a finite bubble of observability and we can never leave.
• 36:34
  Speaker 2: We really are. Our knowledge isn't just bounded by the
• 36:38
  Speaker 2: microscopic weirdness of quantum theory. It is physically literally bounded
• 36:42
  Speaker 2: by the geometry and the history of the universe itself.
• 36:45
  Speaker 1: Okay, let's zoom out.
• 36:46
  Speaker 2: We have to set the scale here to understand the cage.
• 36:49
  Speaker 2: The universe, according to our best cosmological models, is approximately
• 36:53
  Speaker 2: thirteen point eight billion years old. Because nothing in the
• 36:57
  Speaker 2: universe can travel faster than the speed of light. Common
• 36:59
  Speaker 2: sense might tell you that we can only see things
• 37:01
  Speaker 2: that are a maximum of thirteen point eight billion light
• 37:04
  Speaker 2: years away from us in any direction, right.
• 37:06
  Speaker 1: Because light from further away wouldn't have had enough time
• 37:09
  Speaker 1: to reach our telescopes. Yet.
• 37:10
  Speaker 2: That would be true in a static universe, But we
• 37:13
  Speaker 2: live in an expanding universe. The space between galaxies is stretching,
• 37:16
  Speaker 2: and it has been stretching ever since the Big Bang.
• 37:19
  Speaker 1: I always struggle with this space itself is stretching, like
• 37:22
  Speaker 1: the emptiness is getting bigger. How does nothing stretch?
• 37:24
  Speaker 2: It's a concept called metric expansion. Imagine you have a
• 37:28
  Speaker 2: loaf of raisin bread dough. You put it in the oven,
• 37:31
  Speaker 2: and the dough rises and expands.
• 37:33
  Speaker 1: Okay, I see the dough rising.
• 37:35
  Speaker 2: The raisins aren't swimming or moving through the dough. The
• 37:38
  Speaker 2: dough itself is swelling, pushing all the raisins further apart
• 37:41
  Speaker 2: from each other. In this analogy, the raisins are galaxies
• 37:45
  Speaker 2: and the dough is the fabric of space time. Well,
• 37:48
  Speaker 2: that makes sense because space time has been stretching for
• 37:50
  Speaker 2: a thirteen point eight billion years. The light that started
• 37:53
  Speaker 2: traveling toward us thirteen point eight billion years ago came
• 37:56
  Speaker 2: from objects that have now been pushed much much further away.
• 38:00
  Speaker 1: So how big is our actual visible bubble?
• 38:02
  Speaker 2: Because of that stretching, the actual edge of our observable universe,
• 38:06
  Speaker 2: what we call our cosmic horizon, is currently about forty
• 38:10
  Speaker 2: six billion light years away in every direction forty six billion. Okay,
• 38:14
  Speaker 2: that sphere forms our absolute bubble of observability. But here
• 38:18
  Speaker 2: is the terrifying truth that limits our science. The further
• 38:22
  Speaker 2: away you look, the faster the space between us and
• 38:25
  Speaker 2: those galaxies is expanding, and past a certain distance, the
• 38:29
  Speaker 2: cumulative stretching of space means that distant galaxies are receding
• 38:32
  Speaker 2: from us faster than the speed of light.
• 38:34
  Speaker 1: Hold on, Einstein's whole thing was that nothing can go
• 38:37
  Speaker 1: faster than the speed of light. It's the ultimate cosmic
• 38:41
  Speaker 1: speed limit.
• 38:41
  Speaker 2: It is the speed limit for things moving through space.
• 38:44
  Speaker 2: No spaceship, no particle, no ray of light can travel
• 38:47
  Speaker 2: through the fabric of space faster than light. But space
• 38:51
  Speaker 2: itself is under no such restriction.
• 38:53
  Speaker 1: Wait, really, space can just do whatever it wants.
• 38:55
  Speaker 2: The fabric of space time is allowed to stretch at
• 38:58
  Speaker 2: any speed at once because aus. The universe is so
• 39:01
  Speaker 2: vast and the stretching is cumulative. Objects beyond our cosmic
• 39:04
  Speaker 2: horizon are being carried away from us faster than their
• 39:07
  Speaker 2: light can travel toward us.
• 39:08
  Speaker 1: It's like trying to run on a treadmill that is
• 39:10
  Speaker 1: moving backwards faster than you can sprint. You'll never reach
• 39:13
  Speaker 1: the front exactly.
• 39:14
  Speaker 2: And because of that, light from objects beyond that forty
• 39:18
  Speaker 2: six billion light year horizon will literally never reach us.
• 39:22
  Speaker 2: Even if humanity survives for another trillion years, even if
• 39:26
  Speaker 2: we build telescopes the size of a solar system, the
• 39:29
  Speaker 2: space between us and them is growing faster than the
• 39:31
  Speaker 2: light can cross it.
• 39:32
  Speaker 1: That's depressing.
• 39:33
  Speaker 2: Those galaxies and whatever physical realities exist out there are
• 39:37
  Speaker 2: permanently physically and mathematically removed from our observable reality. They
• 39:42
  Speaker 2: are dead to us.
• 39:44
  Speaker 1: It's like being on a tiny raft in the middle
• 39:46
  Speaker 1: of a pitch black ocean. We have a flashlight and
• 39:49
  Speaker 1: we can only see as far as our flashlight beam
• 39:51
  Speaker 1: reaches into the fog. We can assume the rest of
• 39:53
  Speaker 1: the ocean is just more of the same water, but
• 39:55
  Speaker 1: we can't actually prove there isn't a giant sea monster
• 39:57
  Speaker 1: or a massive waterfall, just past the a the light,
• 40:00
  Speaker 1: we are totally permanently blind past that line.
• 40:03
  Speaker 2: We can't ever see past the beam.
• 40:05
  Speaker 1: So what do physicists actually think is out there in
• 40:08
  Speaker 1: the dark?
• 40:08
  Speaker 2: That is where cosmology starts bordering on the metaphysical. Our
• 40:12
  Speaker 2: best models of the early universe include a theory called
• 40:15
  Speaker 2: inflationary cosmology. This suggests that right after the Big Bang,
• 40:19
  Speaker 2: space expanded at an unbelievably violent exponential rate for a
• 40:23
  Speaker 2: fraction of.
• 40:24
  Speaker 1: A second just blew up instantly.
• 40:26
  Speaker 2: The equations that describe this inflation strongly suggest that the
• 40:29
  Speaker 2: process didn't just happen once and stop everywhere.
• 40:32
  Speaker 1: It might be eternal eternal inflation, meaning it's still happening. Yes.
• 40:37
  Speaker 2: This leads directly to the concept of the multiverse. The
• 40:40
  Speaker 2: mathematical models suggest that our entire visible universe is just
• 40:44
  Speaker 2: one tiny, relatively calm bubble that stopped inflating, situated within
• 40:49
  Speaker 2: a vast, endlessly boiling ocean of other universes that are
• 40:53
  Speaker 2: still inflating and spawning new.
• 40:55
  Speaker 1: Bubbles bubbles inside bubbles.
• 40:56
  Speaker 2: And if we look at string theory, which is our
• 40:58
  Speaker 2: most rigorous mathematical tempt to unite the gravity of Einstein
• 41:01
  Speaker 2: with the quantum mechanets we talked about earlier. It presents
• 41:04
  Speaker 2: us with something called the string theory landscape.
• 41:06
  Speaker 1: What is a landscape?
• 41:07
  Speaker 2: String theory requires extra dimensions of space, up to eleven
• 41:10
  Speaker 2: dimensions in total. Because we only see three dimensions of space,
• 41:14
  Speaker 2: the theory says the other extra dimensions must be curled
• 41:17
  Speaker 2: up or compactified into microscopic shapes at every.
• 41:21
  Speaker 1: Point in space, Okay, hidden dimensions.
• 41:23
  Speaker 2: The math of string theory allows for an absolutely mind
• 41:26
  Speaker 2: boggling number of possible ways to fold up those extra dimensions.
• 41:31
  Speaker 2: Each different fold, each different configuration represents a different vacuum
• 41:35
  Speaker 2: state with entirely different physical properties.
• 41:37
  Speaker 1: How many possible configurations are we talking about?
• 41:39
  Speaker 2: Estimates put it at around ten to the power of
• 41:42
  Speaker 2: five hundred possible vacuum states.
• 41:44
  Speaker 1: That's a one with five hundred zeros.
• 41:46
  Speaker 2: That is a one followed by five hundred zeros. To
• 41:49
  Speaker 2: put that in perspective, they're only about ten to the
• 41:52
  Speaker 2: power of eighty atoms in our entire observable universe. Ten
• 41:56
  Speaker 2: to the five hundred is an inconceivably massive number.
• 41:58
  Speaker 1: It's practically infinity.
• 42:00
  Speaker 2: Ziverse series suggests that out there beyond our cosmic horizon,
• 42:03
  Speaker 2: in all those other inflating bubbles. Every single one of
• 42:06
  Speaker 2: those ten to the five hundred configurations is being realized.
• 42:09
  Speaker 2: Each bubble universe would have completely different fundamental laws of physics.
• 42:13
  Speaker 1: So you're saying, in another bubble, gravity might repel instead
• 42:16
  Speaker 1: of a tract.
• 42:17
  Speaker 2: Yes. In one bubble, the mass of an electron might
• 42:20
  Speaker 2: be ten times heavier, which means atoms could never form.
• 42:24
  Speaker 2: In another bubble, there might only be two dimensions of space.
• 42:28
  Speaker 2: In another, the strong nuclear force might be too weak
• 42:30
  Speaker 2: to hold protons together, resulting in a universe filled with
• 42:34
  Speaker 2: nothing but drifting, isolated particles, which means.
• 42:37
  Speaker 1: Our local laws of physics, the ones we teach in
• 42:39
  Speaker 1: textbooks and think are universal absolute truths, might just be
• 42:42
  Speaker 1: a random environmental accident.
• 42:44
  Speaker 2: That is a very real possibility. This forces physicists to
• 42:47
  Speaker 2: grapple with nthropic reasoning. For decades, scientists have wondered, why
• 42:52
  Speaker 2: do we see the universe we do. Why is the
• 42:55
  Speaker 2: math perfectly balanced to allow for stars to ignite, for
• 42:58
  Speaker 2: carbon deform, and for life time to evolve.
• 43:00
  Speaker 1: Why are we so lucky?
• 43:01
  Speaker 2: The anthropic answer is simple, but deeply unsatisfying to many,
• 43:06
  Speaker 2: because if the laws weren't perfectly balanced, to allow for life,
• 43:09
  Speaker 2: we wouldn't be here to observe them. We just happened
• 43:11
  Speaker 2: to live in one of the incredibly rare lucky bubbles
• 43:14
  Speaker 2: that permits complex chemistry. Out of ten to the five
• 43:17
  Speaker 2: hundred dead chaotic ones, Okay, I.
• 43:19
  Speaker 1: Have to push back on this. If string theory predicts
• 43:22
  Speaker 1: ten to the five hundred universes, but we can literally
• 43:25
  Speaker 1: never ever observe them because they're expanding away from us
• 43:29
  Speaker 1: past a cosmic horizon we can never cross. Is that
• 43:32
  Speaker 1: even physics anymore? Or have we accidentally crossed into philosophy
• 43:36
  Speaker 1: and religion? Because if you can't observe it and you
• 43:38
  Speaker 1: can't test it, how is it science.
• 43:40
  Speaker 2: You have hit the exact nerve that divides the physics
• 43:43
  Speaker 2: community today. It is a massive point of tension. Traditional
• 43:47
  Speaker 2: science relies on empirical falsification. As philosopher Karl Popper argued,
• 43:52
  Speaker 2: if you can't test a hypothesis and potentially prove it wrong,
• 43:55
  Speaker 2: you are doing metaphysics, not science.
• 43:57
  Speaker 1: Right, You have to be able to test it.
• 43:59
  Speaker 2: We usually rely on the cosmological principle, the basic assumption
• 44:02
  Speaker 2: that the universe looks basically the same everywhere on large
• 44:04
  Speaker 2: enough scales. But extrapolating our local laws pasted a permanently
• 44:08
  Speaker 2: uncrossable horizon is a massive leap of faith, not direct observation.
• 44:13
  Speaker 2: The cosmic horizon acts as a permanent physical veil.
• 44:16
  Speaker 1: So how do the multiverse proponents justify it?
• 44:19
  Speaker 2: Physicists who support it, like Sean Carroll or Leonard Suskind
• 44:23
  Speaker 2: argue that if a mathematical theory like eternal inflation or
• 44:27
  Speaker 2: string theory elegantly explains a wide variety of phenomena that
• 44:30
  Speaker 2: we can see and test, we should trust its mathematical
• 44:34
  Speaker 2: predictions about the things we can't see. They argue that
• 44:36
  Speaker 2: demanding direct observation of everything is an outdated view of science.
• 44:41
  Speaker 1: But the critics don't buy that.
• 44:42
  Speaker 2: Critics like Sabine Hausenfelder or Peter White argue vehemently that
• 44:46
  Speaker 2: if a theory can predict literally anything across ten to
• 44:49
  Speaker 2: the five hundred universes, then it practically predicts nothing at all.
• 44:54
  Speaker 2: If it is untestable, it belongs in the realm of philosophy.
• 44:57
  Speaker 2: We are fundamentally caged by our.
• 44:59
  Speaker 1: Horizon, and it's not just the very edge of the universe.
• 45:01
  Speaker 1: It's a problem. We have massive, glaring mysteries right here
• 45:05
  Speaker 1: in our own visible bubble. Things we can observe but
• 45:07
  Speaker 1: can't explain. Dark energy, for example.
• 45:10
  Speaker 2: Dark energy is perhaps the greatest embarrassment in modern observational physics.
• 45:15
  Speaker 2: In nineteen ninety eight, astronomers studying distant supernova's discovered something
• 45:19
  Speaker 2: that shocked the world. Not only is the universe expanding,
• 45:22
  Speaker 2: but the rate of that expansion is accelerating.
• 45:25
  Speaker 1: It's speeding up.
• 45:26
  Speaker 2: The galaxies are flying apart faster and faster every day.
• 45:29
  Speaker 2: We call the mysterious force driving this acceleration dark energy.
• 45:34
  Speaker 2: And based on the rate of acceleration, dark energy makes
• 45:36
  Speaker 2: up roughly sixty eight percent of the entire mass energy
• 45:40
  Speaker 2: content of the universe.
• 45:41
  Speaker 1: Sixty eight percent more than two thirds of the universe.
• 45:44
  Speaker 1: And we don't know what it is.
• 45:45
  Speaker 2: We have absolutely no idea what its microscopic origin is.
• 45:48
  Speaker 2: Is it a cosmological constant which Einstein originally proposed as
• 45:52
  Speaker 2: a fudge factor to keep the universe static. If it's
• 45:55
  Speaker 2: a cosmological constant, it means empty space itself inherently possesses
• 45:59
  Speaker 2: a repulsive energy, and the bigger space gets, the more
• 46:01
  Speaker 2: energy there is. What's the alternative or is it a
• 46:04
  Speaker 2: dynamic changing field sometimes called quintessence, that might shift over
• 46:09
  Speaker 2: time depending on what actually is the ultimate fate of
• 46:12
  Speaker 2: the universe changes drastically. It might expand forever until everything
• 46:16
  Speaker 2: freezes in a big freeze, or the dark energy might
• 46:18
  Speaker 2: strengthen and literally rip space, time and atoms apart in
• 46:22
  Speaker 2: a big rip.
• 46:22
  Speaker 1: And we just can't test it.
• 46:24
  Speaker 2: We don't know, and because it only interacts on unbelievably
• 46:26
  Speaker 2: massive cosmic scales, we are structurally limited in how we
• 46:30
  Speaker 2: can test it in a laboratory and.
• 46:32
  Speaker 1: Then hiding out there in the dark. There are black holes,
• 46:35
  Speaker 1: which act as their own kind of physical cage.
• 46:37
  Speaker 2: Black holes are the ultimate hard horizon within our own galaxy.
• 46:41
  Speaker 2: The boundary of a black hole is called the event horizon.
• 46:44
  Speaker 2: It is a mathematical sphere marking the point of no return.
• 46:48
  Speaker 1: Right where gravity is just too strong.
• 46:50
  Speaker 2: Within that sphere, gravity is so intense that the escape
• 46:53
  Speaker 2: velocity exceeds the speed of light. Because nothing can travel
• 46:57
  Speaker 2: faster than light, absolutely no light, matter or in information
• 47:00
  Speaker 2: can ever escape from inside. The interior of a black
• 47:03
  Speaker 2: hole is completely hidden from the rest of the external universe.
• 47:07
  Speaker 2: It is a region of space mathematically and physically cordoned off.
• 47:11
  Speaker 1: But didn't Stephen Hawking show that black holes aren't completely black.
• 47:15
  Speaker 1: They leak, right, he did.
• 47:17
  Speaker 2: In nineteen seventy four. Hawking applied quantum mechanics to the
• 47:21
  Speaker 2: edge of the event horizon and prove that black holes
• 47:24
  Speaker 2: must slowly leak thermal radiation now called Hawking radiation. Because
• 47:28
  Speaker 2: they are radiating energy away over trillions upon trillions of years,
• 47:32
  Speaker 2: black holes will slowly shrink and eventually evaporate away into
• 47:36
  Speaker 2: absolute nothingness.
• 47:37
  Speaker 1: Okay, so they eventually disappear.
• 47:39
  Speaker 2: Why is that a problem because it creates the famous
• 47:41
  Speaker 2: black hole information paradox. Let's say you take an encyclopedia
• 47:46
  Speaker 2: which contains highly specific information, and you toss it into
• 47:49
  Speaker 2: a black hole. For billions of years it sits inside,
• 47:53
  Speaker 2: then the black hole slowly evaporates into random, featureless thermal radiation.
• 48:00
  Speaker 1: Encyclopedia gets burned up.
• 48:01
  Speaker 2: The encyclopedia seems to be completely destroyed, But a fundamental,
• 48:05
  Speaker 2: unbreakable rule of quantum mechanics, a principle called unitarity, states
• 48:10
  Speaker 2: that quantum information can never ever be truly destroyed. In
• 48:13
  Speaker 2: the universe. You must always be able to run the
• 48:16
  Speaker 2: equations backward to see how things started.
• 48:18
  Speaker 1: But if the black hole evaporates into random heat. The
• 48:21
  Speaker 1: information is gone. You can't rebuild the book from.
• 48:24
  Speaker 2: The heat, exactly the paradox. So does the Hawking radiation
• 48:27
  Speaker 2: somehow secretly contain the scrambled, encoded information of the encyclopedia
• 48:32
  Speaker 2: as it leaks out, or is the information truly lost
• 48:35
  Speaker 2: forever when the singularity vanishes.
• 48:37
  Speaker 1: If it's lost, you break quantum mechanics.
• 48:40
  Speaker 2: You completely break the foundations of quantum theory. This paradox
• 48:44
  Speaker 2: has sparked decades of furious, incredibly complex debate. Theoretical physicists
• 48:49
  Speaker 2: have proposed wild ideas to solve it, like what some
• 48:52
  Speaker 2: suggested firewalls, a blazing ring of high energy particles right
• 48:56
  Speaker 2: at the event horizon that incinerates anything falling in in
• 48:59
  Speaker 2: code the information on the surface. Others invoke the holographic principle,
• 49:04
  Speaker 2: arguing the information is plastered on the two D boundary
• 49:07
  Speaker 2: and slowly leaks off. But they all remain purely theoretical,
• 49:11
  Speaker 2: and the biggest problem of all lies at the very
• 49:13
  Speaker 2: center of the black hole, the singularity.
• 49:16
  Speaker 1: The point of infinite density.
• 49:18
  Speaker 2: That's what the math says, but physicists hate infinities. When
• 49:22
  Speaker 2: a physical theory spits out in infinity. It usually means
• 49:25
  Speaker 2: the theory has broken down. The singularity is the point
• 49:28
  Speaker 2: where Einstein's equations of general relativity fail entirely. The curvature
• 49:33
  Speaker 2: of space time becomes infinite. Our mathematical descriptions simply stop working.
• 49:38
  Speaker 1: Because to understand the singularity, you are dealing with something
• 49:40
  Speaker 1: that has massive star crouching gravity but is compressed to
• 49:44
  Speaker 1: a microscopic quantum size. You need a theory that marries
• 49:48
  Speaker 1: the massive scale of relativity with the microscopic scale of
• 49:50
  Speaker 1: quantum mechanics. You need a unified theory of quantum gravity.
• 49:55
  Speaker 2: Exactly what we need. We need to be able to
• 49:56
  Speaker 2: mathematically probe the Plank scale.
• 49:58
  Speaker 1: What is the Plank scale.
• 50:00
  Speaker 2: It is the absolute smallest meaningful measurement in the universe.
• 50:04
  Speaker 2: It is the realm of ten to the power of
• 50:06
  Speaker 2: negative thirty five meters and time intervals of ten to
• 50:10
  Speaker 2: the negative forty three seconds.
• 50:12
  Speaker 1: That is impossibly small.
• 50:13
  Speaker 2: It is the incredibly tiny scale where the smooth, continuous
• 50:17
  Speaker 2: fabric of Einstein's spacetime breaks down completely and starts to
• 50:20
  Speaker 2: get violently churned up by quantum fluctuations. It becomes a
• 50:24
  Speaker 2: chaotic quantum foam. But here is the practical insurmountable physical
• 50:29
  Speaker 2: limit to understanding it. To see things that are incredibly small,
• 50:33
  Speaker 2: you need a microscope that uses incredibly high energy particles.
• 50:37
  Speaker 1: Why do you need high energy to see small things?
• 50:39
  Speaker 2: Think about waves again. To probe a tiny distance, you
• 50:42
  Speaker 2: need a wave with a very very short wavelength, and
• 50:45
  Speaker 2: in quantum mechanics, shorter wavelengths require vastly higher energies to
• 50:49
  Speaker 2: smash particles together with enough energy. To create a wavelength
• 50:52
  Speaker 2: short enough to probe the Plank scale, you need a
• 50:55
  Speaker 2: massive particle accelerator like cirn. Current accelerators like the large
• 50:59
  Speaker 2: Hadron cl lighter in Europe are an incredible feat of engineering.
• 51:03
  Speaker 2: They form a ring twenty seven kilometers around, but they
• 51:06
  Speaker 2: are vastly, almost lappably too weak to probe the plank scale.
• 51:11
  Speaker 1: How much bigger would a quietter need to be to
• 51:13
  Speaker 1: actually see the.
• 51:13
  Speaker 2: Quantum phone To generate the energy required to test theories
• 51:17
  Speaker 2: like string theory or loop quantum gravity directly at the
• 51:20
  Speaker 2: plank to scale, you would need a particle accelerator roughly
• 51:24
  Speaker 2: the size of the entire Milky Way galaxy, a.
• 51:27
  Speaker 1: Galaxy size machine. Okay, yeah, that's.
• 51:29
  Speaker 2: Not happening constrained by the sheer energy requirements, the material
• 51:32
  Speaker 2: limits of what we can build, and the universe's own
• 51:35
  Speaker 2: physical dimensions. We may simply never ever build machines powerful
• 51:39
  Speaker 2: enough to see the ultimate foundation of reality. We are
• 51:42
  Speaker 2: boxed out by energy limits.
• 51:44
  Speaker 1: So we've hit the edge of the expanding universe, and
• 51:46
  Speaker 1: we've hit the bottom of the quantum realm. We are
• 51:49
  Speaker 1: boxed in by the speed of light, expanding space, unresolvable paradoxes,
• 51:54
  Speaker 1: and the sheer galactic energy requirements needed to zoom in
• 51:57
  Speaker 1: any further. But there's an even more intimate boundary we
• 52:01
  Speaker 1: have to confront before we finish mapping the edge. It's
• 52:04
  Speaker 1: a very instrument we're using to think about all of this.
• 52:06
  Speaker 1: In the first place, we have to talk about the
• 52:08
  Speaker 1: hardware problem. We have to talk about the biological limits
• 52:10
  Speaker 1: of human cognition.
• 52:12
  Speaker 2: This might be the most humbling horizon of all because
• 52:15
  Speaker 2: it turns the lens back on ourselves. We like to
• 52:18
  Speaker 2: think of our brains as perfect, objective, truth seeking machines,
• 52:22
  Speaker 2: but human cognition is first and foremost a messy biological
• 52:27
  Speaker 2: evolutionary tool. It's an organ It was designed by natural
• 52:30
  Speaker 2: selection over millions of years for one primary overriding purpose, survival.
• 52:37
  Speaker 2: It was emphatically not designed for unraveling the ultimate truths
• 52:40
  Speaker 2: of the cosmos.
• 52:41
  Speaker 1: It's a very weird, uncomfortable thing to step back and
• 52:44
  Speaker 1: think about your own brain as just a survival organ
• 52:47
  Speaker 1: trying to keep a primate alive, rather than a perfect
• 52:50
  Speaker 1: mirror reflecting reality.
• 52:51
  Speaker 2: It is uncomfortable, but it is exactly what the field
• 52:53
  Speaker 2: of evolutionary epistemology teaches us. Consider the environment. Our brains
• 52:58
  Speaker 2: evolved in the African savannah to survive there. Our neural
• 53:02
  Speaker 2: architecture got incredibly highly optimized for certain.
• 53:05
  Speaker 1: Specific tasks like hunting and gathering.
• 53:07
  Speaker 2: We became masters of pattern recognition so we could spot
• 53:10
  Speaker 2: the subtle camouflage of a predator in the tall grass.
• 53:14
  Speaker 2: We developed intense social navigation skills so we could cooperate
• 53:18
  Speaker 2: in complex tribes, track alliances, and detect deception. And we
• 53:22
  Speaker 2: evolved an intuitive grasp of classical mechanics. If I throw
• 53:26
  Speaker 2: a rock or a spear, your brain can instantly and
• 53:28
  Speaker 2: intuitively calculate a parabolic trajectory and predict exactly where it
• 53:32
  Speaker 2: will land.
• 53:32
  Speaker 1: Right, our brains are perfectly optimized for medium sized objects
• 53:36
  Speaker 1: moving at medium steeds.
• 53:37
  Speaker 2: That is the limit of our intuitive umwelt, our perceived world.
• 53:41
  Speaker 2: Our brains were emphatically not built to intuitively grasp an
• 53:44
  Speaker 2: eleven dimensional string theory landscape. They were not built to
• 53:47
  Speaker 2: understand the non locality of entangled quantum particles or objects
• 53:51
  Speaker 2: moving at ninety nine percent the speed of light where
• 53:54
  Speaker 2: time slows down. Evolution favors fitness and survival, not objective
• 53:58
  Speaker 2: absolute truth.
• 53:59
  Speaker 1: Can you give me example of evolution choosing survival over truth.
• 54:03
  Speaker 2: Think about optical illusions or how we perceive color. Color
• 54:07
  Speaker 2: doesn't actually exist in the physical universe. The universe just
• 54:10
  Speaker 2: has electromagnetic waves of varying frequencies.
• 54:12
  Speaker 1: Right, It's just waves, but our.
• 54:14
  Speaker 2: Brains translate a specific frequency into the vibrant, subjective experience
• 54:18
  Speaker 2: of red. Because recognizing a ripe fruit against a background
• 54:22
  Speaker 2: of green leaves offered a massive survival advantage to our ancestors.
• 54:27
  Speaker 2: If a distorted perception of reality helps an organism survive
• 54:30
  Speaker 2: and reproduce better than a perfectly accurate perception, evolution will
• 54:34
  Speaker 2: hardwire that distortion into the visual cortex.
• 54:37
  Speaker 1: So our senses are lying to us to keep us alive.
• 54:40
  Speaker 2: Our senses, our logic, and our reasoning are deeply fundamentally
• 54:44
  Speaker 2: filtered through a biological lens.
• 54:46
  Speaker 1: It's like trying to understand the fundamental fabric of reality
• 54:49
  Speaker 1: using a tool that was only ever designed to dodge
• 54:52
  Speaker 1: tigers and forage for berries. Which brings us to the biggest,
• 54:56
  Speaker 1: most intractable mystery of the brain itself, the hard problem
• 55:00
  Speaker 1: of consciousness.
• 55:01
  Speaker 2: The philosopher David Schamers coined the term the hard problem
• 55:04
  Speaker 2: in the nineteen nineties, and it remains the deepest chasm
• 55:07
  Speaker 2: in science today. Chalmers distinguished between the easy problems of
• 55:12
  Speaker 2: the brain and the hard problem.
• 55:14
  Speaker 1: What are the easy problems?
• 55:15
  Speaker 2: Neuroscience is currently making incredible strides on the easy problems,
• 55:19
  Speaker 2: though to be fair, they aren't actually easy. We can
• 55:23
  Speaker 2: map neural correlates of consciousness. We can put someone in
• 55:26
  Speaker 2: an fMRI machine, show them a picture, and say, ah,
• 55:30
  Speaker 2: this specific cluster of neurons in the visual cortex is firing.
• 55:33
  Speaker 1: We could see the wiring.
• 55:35
  Speaker 2: We can track the precise electro chemical signals of a
• 55:37
  Speaker 2: pain response traveling up the nervous system from a stubbed
• 55:40
  Speaker 2: toe to the brain. We can even build advanced AI
• 55:43
  Speaker 2: systems that can mimic complex human behavior, hold conversations and
• 55:47
  Speaker 2: solve problems.
• 55:48
  Speaker 1: Wait, if we keep mapping in the brain, if we
• 55:50
  Speaker 1: go neuron by neurons, sentouts by synaps mapping every chemical interaction, Yeah,
• 55:54
  Speaker 1: won't we eventually just find the exact physical spark that
• 55:58
  Speaker 1: equals the feeling of experiencing the color red. Doesn't the
• 56:01
  Speaker 1: whole puzzle eventually get solved?
• 56:03
  Speaker 2: That is exactly the core of the hard problem. Chalmers
• 56:06
  Speaker 2: argues that no matter how perfectly you map the physical
• 56:09
  Speaker 2: mechanics of the brain, there remains an unbridgable explanatory gap.
• 56:14
  Speaker 2: You can perfectly describe the physics of a six hundred
• 56:17
  Speaker 2: nanometer wavelength of light bouncing off an apple and hitting
• 56:20
  Speaker 2: the retina. You can perfectly describe the chemistry of the
• 56:23
  Speaker 2: neurotransmitters firing across the synapse in the visual cortex.
• 56:27
  Speaker 1: You have the whole map.
• 56:27
  Speaker 2: You can have a one hundred percent complete objective map
• 56:30
  Speaker 2: of the mechanics, but absolutely nothing in that purely physical
• 56:34
  Speaker 2: mechanical description explains why those physical processes give rise to
• 56:38
  Speaker 2: the subjective, rich, first person experience of seeing red. The
• 56:42
  Speaker 2: inner feeling, what philosophers call the quality of the experience,
• 56:46
  Speaker 2: is missing from the physics.
• 56:47
  Speaker 1: Because You could theoretically have a biological or mechanical system
• 56:50
  Speaker 1: that processes all that visual data perfectly reacts to it,
• 56:54
  Speaker 1: avoids obstacles, but feels absolutely nothing inside. The lights are on,
• 56:59
  Speaker 1: but nobody is home.
• 57:00
  Speaker 2: Yes, philosophers call that a philosophical zombie, a creature that
• 57:04
  Speaker 2: looks human, acts human, and even screens when you poke it,
• 57:07
  Speaker 2: but lacks any inner subjective experience. Why aren't we zombies?
• 57:11
  Speaker 2: How does three pounds of wet meat suddenly generate a mind?
• 57:14
  Speaker 1: It's the ghost in the machine.
• 57:16
  Speaker 2: Science deals exclusively in objective third person measurable facts, mass,
• 57:22
  Speaker 2: charge velocity, but consciousness is entirely subjective in first person,
• 57:27
  Speaker 2: it is private. No physical experiment involving scalpels or microscope
• 57:32
  Speaker 2: seems fundamentally capable of bridging that gap, because you cannot
• 57:35
  Speaker 2: measure an experience.
• 57:36
  Speaker 1: Trying to understand quantum gravity or the origins of subjective
• 57:40
  Speaker 1: consciousness using a biological human brain is like trying to
• 57:43
  Speaker 1: run a next gen photorealistic virtual reality simulation on a
• 57:47
  Speaker 1: clunky desktop computer from nineteen ninety five. The hardware simply
• 57:51
  Speaker 1: wasn't designed for the software. We just lack the processing
• 57:54
  Speaker 1: power and the right kind of architecture.
• 57:56
  Speaker 2: There is a philosopher named Colin McGinn who formalized this
• 57:59
  Speaker 2: exact intuition. He calls it cognitive closure.
• 58:01
  Speaker 1: Cognitive closure.
• 58:03
  Speaker 2: The concept is simple but humbling. Just as a dog
• 58:07
  Speaker 2: is a perfectly intelligent creature in its own evolutionary context,
• 58:11
  Speaker 2: its brain is completely cognitively closed to understanding calculus.
• 58:16
  Speaker 1: Right, you can't teach a dog math.
• 58:18
  Speaker 2: It's not that the dog just needs more time to study.
• 58:20
  Speaker 2: It's that, no matter how long you sit a dog
• 58:22
  Speaker 2: in front of a chalkboard, it will never ever grasp
• 58:25
  Speaker 2: differential equations. It simply lacks the necessary cognitive architecture. McGinn
• 58:30
  Speaker 2: suggests that human beings, as biological organisms, might similarly be
• 58:34
  Speaker 2: cognitively closed to certain ultimate truths about the universe.
• 58:38
  Speaker 1: So there might be concepts about the true nature of time,
• 58:40
  Speaker 1: or how infinity works, or how consciousness emerges from matter
• 58:43
  Speaker 1: that are just fundamentally beyond the limits of our biological hardware.
• 58:47
  Speaker 2: Precisely the point we think in distinctly human constructs. We
• 58:50
  Speaker 2: structure reality through narratives, linguistic categories, and classical linear causal
• 58:54
  Speaker 2: chains cause and effect, But the universe is under no
• 58:57
  Speaker 2: obligation to adhere to those humans constructs.
• 59:00
  Speaker 1: Our brain is a filter.
• 59:02
  Speaker 2: Take the true nature of time. For instance, we experience
• 59:05
  Speaker 2: time as a flowing river moving from past to future,
• 59:08
  Speaker 2: but physics tells us time is just another dimension woven
• 59:11
  Speaker 2: into space time. Does time actually flow or is our
• 59:15
  Speaker 2: perception of flow just a neurological illusion created by how
• 59:19
  Speaker 2: memory works? Is mathematics something we objectively discover out there
• 59:23
  Speaker 2: in the universe? Or is it a tool we invented
• 59:25
  Speaker 2: a reflection of how our specific brains evolve to process patterns.
• 59:29
  Speaker 1: It gets really circular.
• 59:30
  Speaker 2: These questions strain our intuitions because we are trying to
• 59:33
  Speaker 2: use the very tool our brain, whose nature we are questioning.
• 59:36
  Speaker 2: It's a closed loop.
• 59:37
  Speaker 1: But what if we bypass our biology? Even if our
• 59:40
  Speaker 1: brains are clunky nineteen ninety five desktops, we are currently
• 59:44
  Speaker 1: building superintelligent AI. If we build a machine a million
• 59:48
  Speaker 1: times smarter than us, can't we just cheat the system
• 59:51
  Speaker 1: and have it figure out the ultimate truths for us.
• 59:53
  Speaker 2: It's a compelling idea, but even advanced AI runs into
• 59:56
  Speaker 2: fundamental roadblocks. AI might extend our cognitive reach exponentially, but
• 1:00:01
  Speaker 2: it still inherits human designed logical architectures, and more importantly,
• 1:00:05
  Speaker 2: it inherits the absolute physical limits of computation.
• 1:00:08
  Speaker 1: Because it's still a physical machine.
• 1:00:10
  Speaker 2: A superintelligent AI still has to operate within the physical
• 1:00:13
  Speaker 2: bounds of the universe. It still requires energy, it still
• 1:00:16
  Speaker 2: generates heat, and it is still constrained by the speed
• 1:00:19
  Speaker 2: of light for processing information across its own circuits. Furthermore,
• 1:00:24
  Speaker 2: if the universe contains truly non computable elements, as we
• 1:00:27
  Speaker 2: discussed with Turing's halting problem in Girdle's incompleteness, no machine,
• 1:00:31
  Speaker 2: no matter how hyperintelligent or massive, could ever fully simulate
• 1:00:36
  Speaker 2: or unravel it.
• 1:00:37
  Speaker 1: Well, let's play Devil's advocate. Let's say hypothetically, a thousand
• 1:00:41
  Speaker 1: years from now, we somehow upgrade our brains, we merge
• 1:00:44
  Speaker 1: with AI, we bypass the quantum blur, and we figure
• 1:00:47
  Speaker 1: out a way to travel past the cosmic horizon. Let's
• 1:00:50
  Speaker 1: say we finally possess all the perfectly understood fundamental puzzle
• 1:00:53
  Speaker 1: pieces of the universe.
• 1:00:54
  Speaker 2: Okay, I'll play along.
• 1:00:55
  Speaker 1: Even if we do all that, putting those pieces together
• 1:00:58
  Speaker 1: creates a completely new type of mystery, which brings us
• 1:01:01
  Speaker 1: to the forest. In the trees, we have to confront
• 1:01:04
  Speaker 1: the limits of complexity, emergence, and the search for meaning.
• 1:01:07
  Speaker 2: This is the final frontier, and it's where we see
• 1:01:10
  Speaker 2: that knowing the fundamental parts of a system does not
• 1:01:12
  Speaker 2: automatically explain the whole. For the last four hundred years,
• 1:01:16
  Speaker 2: science has excelled brilliantly at a philosophy called reductionism, breaking
• 1:01:20
  Speaker 2: things down. Reductionism is the idea that if you want
• 1:01:23
  Speaker 2: understand how a complex clock works, you take it apart
• 1:01:26
  Speaker 2: and look at the gears. It answers the how of
• 1:01:29
  Speaker 2: physical interactions beautifully, But as systems get more complex, reductionism
• 1:01:34
  Speaker 2: begins to fail and science struggles profoundly with the why.
• 1:01:38
  Speaker 1: I think we need to talk about emergence here, because
• 1:01:40
  Speaker 1: it's one thing to understand a single molecule, and it's
• 1:01:43
  Speaker 1: another entirely to understand a hurricane.
• 1:01:45
  Speaker 2: Emergence is a cornerstone of modern complexity theory. It is
• 1:01:49
  Speaker 2: the principle that complex systems develop novel properties that are
• 1:01:53
  Speaker 2: entirely irreducible to their individual parts. Let's take a simple,
• 1:01:56
  Speaker 2: everyday example water. We understand the auto mechanics of hydrogen
• 1:02:01
  Speaker 2: and oxygen atoms perfectly.
• 1:02:03
  Speaker 1: Two hydrogens, one oxygen.
• 1:02:05
  Speaker 2: But if you take a supercomputer and stare at the
• 1:02:07
  Speaker 2: equations for a single isolated H two molecule. You will
• 1:02:12
  Speaker 2: never ever find the property of wetness. Wetness or liquidity,
• 1:02:16
  Speaker 2: or the macroscopic laws of fluid dynamics, or the turbulent
• 1:02:19
  Speaker 2: crash of an ocean wave are emergent properties. They simply
• 1:02:23
  Speaker 2: do not exist at the atomic level. They only come
• 1:02:26
  Speaker 2: into existence when billions of molecules interact in a complex network.
• 1:02:30
  Speaker 1: So knowing the physics of the atom doesn't automatically hand
• 1:02:32
  Speaker 1: you the physics of the wave exactly.
• 1:02:34
  Speaker 2: You need completely new, additional mathematical organizing principles to describe
• 1:02:39
  Speaker 2: the wave. The universe is stratified into levels of complexity.
• 1:02:42
  Speaker 2: Biology emerges from chemistry, but you can't fully explain a living,
• 1:02:46
  Speaker 2: dividing cell just by listing its chemical reactions. Psychology and
• 1:02:50
  Speaker 2: neuroscience emerge from biology, but as we saw with the
• 1:02:53
  Speaker 2: hard problem, you can't explain the subjective mind just by
• 1:02:56
  Speaker 2: looking at neurons.
• 1:02:57
  Speaker 1: The sum is greater than the parts.
• 1:02:59
  Speaker 2: Economics and sooology emerged from psychology. Reductionism is a powerful tool,
• 1:03:03
  Speaker 2: but it eventually hits a hard wall where higher level
• 1:03:06
  Speaker 2: laws become entirely autonomous. You cannot reduce sociology to quantum mechanics.
• 1:03:11
  Speaker 2: The attempt is.
• 1:03:11
  Speaker 1: Absurd, and this limitation hits its absolute staggering peak when
• 1:03:16
  Speaker 1: we ask the ultimate origin question, the one that every
• 1:03:19
  Speaker 1: child eventually asks, Why is there something rather than nothing?
• 1:03:25
  Speaker 2: That is the question that transcends physics entirely. Physicists do
• 1:03:28
  Speaker 2: try to answer it. Of course, we talk about quantum
• 1:03:30
  Speaker 2: fluctuations in a vacuum. We theorize that if you have
• 1:03:33
  Speaker 2: empty space, the laws of quantum mechanics allow virtual particles
• 1:03:37
  Speaker 2: to spontaneously pop into and out of existence. Cosmologists like
• 1:03:42
  Speaker 2: Stephen Hawking and James Hardle proposed the no boundary proposal.
• 1:03:46
  Speaker 2: It's a beautiful mathematical description where the universe doesn't have
• 1:03:49
  Speaker 2: a singular, sharp starting point in time, much like the
• 1:03:53
  Speaker 2: North Pole doesn't have an edge you can fall off.
• 1:03:55
  Speaker 2: These are incredibly elegant mathematical descriptions of how a universe
• 1:03:58
  Speaker 2: might have begun, assuming certain laws of physics were already
• 1:04:01
  Speaker 2: in place.
• 1:04:01
  Speaker 1: That's a massive assumption. It just pushes the problem back
• 1:04:04
  Speaker 1: a step. It completely begs the question, why do the
• 1:04:07
  Speaker 1: specific laws of physics that permit quantum fluctuations exist in
• 1:04:11
  Speaker 1: the first place. Why does the mathematical rule book exist?
• 1:04:14
  Speaker 1: Who or what breathe fire into the equations to make
• 1:04:17
  Speaker 1: them real?
• 1:04:17
  Speaker 2: And that is exactly where empirical science exhausts itself and
• 1:04:21
  Speaker 2: hands the baton to philosophy, metaphysics, and theology. Science is
• 1:04:26
  Speaker 2: the ultimate unrivaled tool for describing how the universe evolves
• 1:04:30
  Speaker 2: given a specific set of initial conditions and fundamental laws,
• 1:04:34
  Speaker 2: but it is fundamentally inherently unequipped to answer why those
• 1:04:38
  Speaker 2: specific laws exist at all instead of some other laws,
• 1:04:41
  Speaker 2: or instead of absolute blank nothingness.
• 1:04:44
  Speaker 1: It makes me think of a musical analogy. Imagine you
• 1:04:47
  Speaker 1: have a futuristic supercomputer that can perfectly analyze a Mozart's symphony.
• 1:04:51
  Speaker 1: The computer could measure the exact microscopic frequency of every
• 1:04:55
  Speaker 1: single sound way moving through the air. It could map
• 1:04:57
  Speaker 1: the physical tension of the violin strings via breeding, analyze
• 1:05:01
  Speaker 1: the acoustics of the concert hall, and perfectly detail the
• 1:05:04
  Speaker 1: biological mechanism of the musician's muscles moving.
• 1:05:07
  Speaker 2: A perfect physical map of the performance.
• 1:05:09
  Speaker 1: Exactly, it would have a one hundred percent complete physical
• 1:05:12
  Speaker 1: reductionist description of the song. But none of that physics,
• 1:05:15
  Speaker 1: no matter how precise, will ever explain why the melody
• 1:05:17
  Speaker 1: makes you cry.
• 1:05:18
  Speaker 2: That is a phenomenal way to frame the boundary. The
• 1:05:21
  Speaker 2: physical description is total and complete, but the meaning, the
• 1:05:25
  Speaker 2: esthetic weight is entirely absent from the equations. Science relies,
• 1:05:29
  Speaker 2: as we discussed on empirical falsification. You formulate a hypothesis,
• 1:05:34
  Speaker 2: you run a physical test, you prove it wrong or right.
• 1:05:37
  Speaker 2: But questions of meaning, purpose, aesthetics, and morality are fundamentally
• 1:05:41
  Speaker 2: outside the bounds of empirical falsification.
• 1:05:44
  Speaker 1: Right, I can't put goodness or beauty in a test
• 1:05:47
  Speaker 1: tube in way you cannot.
• 1:05:48
  Speaker 2: Evolutionary biology can explain the historical origins of cooperation. It
• 1:05:53
  Speaker 2: can show us how altruism helped our primate ancestors survive
• 1:05:56
  Speaker 2: in tribes, share food, and raise offspring. That is the
• 1:05:59
  Speaker 2: objective science of what is. But as the philosopher David
• 1:06:02
  Speaker 2: Hume pointed out centuries ago, you cannot logically derive an
• 1:06:05
  Speaker 2: aught from an is.
• 1:06:06
  Speaker 1: Science just tells you what happens, not what should happen.
• 1:06:09
  Speaker 2: Science cannot tell us what we should do, or what
• 1:06:12
  Speaker 2: is objectively right or wrong. Physics can tell us exactly
• 1:06:15
  Speaker 2: how to split an atom and build a nuclear reactor,
• 1:06:18
  Speaker 2: but it cannot tell us whether we should use that
• 1:06:20
  Speaker 2: reactor to power a hospital or build a bomb to
• 1:06:23
  Speaker 2: destroy city. The scientific method is morally silent, and it.
• 1:06:27
  Speaker 1: Leaves us staring at mysteries like the fine tuning of
• 1:06:30
  Speaker 1: the universe with no real scientific way to resolve them.
• 1:06:34
  Speaker 2: Fine tuning is the perfect example of this silent boundary.
• 1:06:37
  Speaker 2: When we look at the universe, we see that the
• 1:06:39
  Speaker 2: fundamental physical constants, the exact strength of gravity, the specific
• 1:06:43
  Speaker 2: mass of an electron, the rate of cosmic expansion are
• 1:06:47
  Speaker 2: balanced on an unimaginably thin razor's edge.
• 1:06:50
  Speaker 1: Like if they were off by a tiny bit.
• 1:06:52
  Speaker 2: If you tweak the strength of the strong nuclear force
• 1:06:54
  Speaker 2: by just a fraction of a percent, stars burn out
• 1:06:57
  Speaker 2: too quickly, carbon never forms, and biologue life is impossible.
• 1:07:01
  Speaker 2: The universe appears suspiciously dialed in for complex chemistry.
• 1:07:05
  Speaker 1: So how do we interpret that scientifically?
• 1:07:07
  Speaker 2: That's the problem. The science can only measure the dials,
• 1:07:10
  Speaker 2: it can't tell us who turned them. Does this fine
• 1:07:12
  Speaker 2: tuning imply anthropic selection via massive unseen multiverse where we
• 1:07:17
  Speaker 2: just won the cosmic lottery? Does it imply some form
• 1:07:20
  Speaker 2: of conscious teleological design, or is it just a brute
• 1:07:24
  Speaker 2: mathematical fact a lucky role of the cosmic dice that
• 1:07:28
  Speaker 2: requires no deeper explanation. Science can precisely measure the fine
• 1:07:32
  Speaker 2: tuning down to the tenth decimal place, but the empirical
• 1:07:35
  Speaker 2: evidence for why it is fine tuned remains prominently intrinsically inconclusive.
• 1:07:40
  Speaker 1: Okay, I want to take a breath and look at
• 1:07:41
  Speaker 1: the picture we've painted today, because if I am listening
• 1:07:44
  Speaker 1: to this, I might feel a bit of exidential dread
• 1:07:47
  Speaker 1: creeping in. If we are surrounded on all signs by
• 1:07:49
  Speaker 1: physical horizons we can never cross, trapped by mathematical paradox
• 1:07:53
  Speaker 1: as we can never solve, boxed in by biological cognitive
• 1:07:56
  Speaker 1: limits we can't outgrow, and left with deep questions of
• 1:07:59
  Speaker 1: mean that science can't touch. Does that mean the scientific
• 1:08:03
  Speaker 1: endeavor is fundamentally a tragedy? Are we just doomed to
• 1:08:06
  Speaker 1: be perpetually frustrated primates banging our heads against the glass
• 1:08:09
  Speaker 1: walls of our cage.
• 1:08:10
  Speaker 2: It is very easy to feel that way, but actually
• 1:08:12
  Speaker 2: I believe it's the exact opposite. Recognizing our fundamental boundaries
• 1:08:16
  Speaker 2: does not diminish the majesty of science. It enriches it profoundly.
• 1:08:21
  Speaker 2: When we understand our limits, we strip away our intellectual arrogance.
• 1:08:25
  Speaker 2: It forces us to adopt a deep, essential humility and
• 1:08:28
  Speaker 2: an enduring sense of wonder. How so, think of Isaac Newton,
• 1:08:32
  Speaker 2: the man who literally cracked the code of gravity and motion,
• 1:08:35
  Speaker 2: who ushered in the scientific revolution, didn't view himself as
• 1:08:39
  Speaker 2: an all knowing conqueror of nature. He famously described himself
• 1:08:42
  Speaker 2: toward the end of his life as merely a young
• 1:08:44
  Speaker 2: boy playing on the seashore, diverting himself by occasionally finding
• 1:08:48
  Speaker 2: a smoother pebble or a prettier shell than ordinary, while
• 1:08:51
  Speaker 2: the great vast ocean of truth lay all undiscovered before him.
• 1:08:55
  Speaker 1: That brings us perfectly back to the map analogy we
• 1:08:58
  Speaker 1: started the episode with. We map the beach with incredible precision,
• 1:09:01
  Speaker 1: but the ocean is impossibly vast.
• 1:09:03
  Speaker 2: And Albert Einstein, the man who completely rewrote Newton's universe,
• 1:09:08
  Speaker 2: constantly marveled at the very fact that the universe was
• 1:09:11
  Speaker 2: comprehensible to us at all. He felt that the most
• 1:09:14
  Speaker 2: incomprehensible thing about the universe is that it is comprehensible.
• 1:09:18
  Speaker 2: Why should a universe of chaotic quantum fields and warping
• 1:09:21
  Speaker 2: space time make sense to the brain of a primate.
• 1:09:23
  Speaker 1: It's a miracle. It works at all.
• 1:09:25
  Speaker 2: Modern theoretical physicists today, thinkers like Carlo Rivelli and Sabine
• 1:09:29
  Speaker 2: Hausenfelder argue fiercely that acknowledging our deep ignorance is exactly
• 1:09:34
  Speaker 2: the engine that drives progress. If we arrogantly assumed we
• 1:09:37
  Speaker 2: were on the verge of knowing everything, science would stagnate
• 1:09:40
  Speaker 2: and stop.
• 1:09:41
  Speaker 1: The beauty of hitting the edge is that science progresses
• 1:09:44
  Speaker 1: by constantly expanding the knowable frontier. We launched the James
• 1:09:48
  Speaker 1: Webb Space Telescope, a marvel of engineering, and suddenly we
• 1:09:51
  Speaker 1: are seeing the faint, red shifted light of galaxies that
• 1:09:54
  Speaker 1: formed just hundreds of millions of years after the Big Bang.
• 1:09:58
  Speaker 1: We are revealing galactic extra ructures and complexities that completely
• 1:10:02
  Speaker 1: defy our early models.
• 1:10:03
  Speaker 2: We push the boundary outward every single day.
• 1:10:06
  Speaker 1: We make massive cross disciplinary leaps in quantum computing, blending
• 1:10:10
  Speaker 1: abstract information theory with microscopic physics to manipulate atoms in
• 1:10:15
  Speaker 1: ways Turing never could have imagined.
• 1:10:17
  Speaker 2: We push it outward, and the horizon is always receding.
• 1:10:20
  Speaker 2: But here is the crucial, beautiful part of the scientific process.
• 1:10:25
  Speaker 2: Every single profound answer we find births a dozen new
• 1:10:29
  Speaker 2: unexpected questions. The frontier of human knowledge expands continuously, but
• 1:10:34
  Speaker 2: the circumference of our ignorance, the perimeter where our knowledge
• 1:10:37
  Speaker 2: meets the unknown, expands right along with it. The universe
• 1:10:41
  Speaker 2: is simply not obligated to be fully legible to minds
• 1:10:44
  Speaker 2: like ours.
• 1:10:44
  Speaker 1: It's a tension, a permanent, beautiful tension between our incredible,
• 1:10:48
  Speaker 1: hard won mastery of the cosmos, the fact that we
• 1:10:50
  Speaker 1: can measure an electrons magnetic moment to ten decimal places,
• 1:10:54
  Speaker 1: and our profound humility in the face of the vast
• 1:10:57
  Speaker 1: dark unknown. That tension is what defines the entire human
• 1:11:00
  Speaker 1: scientific endeavor. We are mapping what we can, drawing the
• 1:11:03
  Speaker 1: veins on the leaves, while learning to deeply appreciate the dark,
• 1:11:06
  Speaker 1: unmapped spaces on the map.
• 1:11:08
  Speaker 3: And those dark spaces, those profound questions that may never
• 1:11:12
  Speaker 3: be answered mathematically or physically, are perhaps what make the
• 1:11:15
  Speaker 3: pursuit of knowledge so endlessly Worthwhile science illuminates extraordinary, breath
• 1:11:20
  Speaker 3: taking swaths of existence.
• 1:11:23
  Speaker 2: It is undoubtedly the greatest, most powerful tool humanity has
• 1:11:26
  Speaker 2: ever invented. But the remainder, the permanently veiled truth at
• 1:11:29
  Speaker 2: the edge of the universe remind us that while mathematical
• 1:11:32
  Speaker 2: explanation has fundamental limits, human wonder absolutely does not.
• 1:11:35
  Speaker 1: I want to leave you with a final provocative thought today,
• 1:11:38
  Speaker 1: something for you to just mull over, to explore on
• 1:11:41
  Speaker 1: your own, that builds on the incredible journey we just took.
• 1:11:44
  Speaker 1: We've talked a lot today about how human biology, our
• 1:11:47
  Speaker 1: savannah evolved primate brains filters and limits our understanding of
• 1:11:51
  Speaker 1: ultimate reality. But imagine, just for a second, a completely
• 1:11:56
  Speaker 1: different kind of conscious observer. Imagine a decentralized network worked
• 1:12:00
  Speaker 1: intelligence spread out across an entire galaxy. An entity that
• 1:12:04
  Speaker 1: doesn't perceive time in fleeting biological seconds, but experiences a
• 1:12:08
  Speaker 1: single thought over the course of millions of years. If
• 1:12:12
  Speaker 1: their cognitive hardware, their physical brain, is that radically fundamentally
• 1:12:15
  Speaker 1: different from ours, would they hit the exact same horizons
• 1:12:18
  Speaker 1: we do? Would the microscopic quantum world still look random
• 1:12:22
  Speaker 1: to an entity that massive? Would the hard problem of
• 1:12:25
  Speaker 1: consciousness even exist for a decentralized hive mind. Or is
• 1:12:29
  Speaker 1: our universe a completely different shape, a completely different physical reality,
• 1:12:33
  Speaker 1: depending entirely on the specific kind of mind that looks
• 1:12:35
  Speaker 1: at it. Something for you to ponder the next time
• 1:12:37
  Speaker 1: you step outside, look up at the stars and realize
• 1:12:42
  Speaker 1: you are standing on the shoreline of that vast, undrawable ocean.