Chapter 7: The Theory of Everything Explained (Lecture 7)

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Welcome back to the Deep Dive.

Today we are strapping in for what is probably the ultimate scientific road trip.

I think that's a good way to put it.

We're heading straight for the most ambitious goal in all of theoretical physics.

We're talking about the search for the ultimate, complete, and fully consistent description of the entire universe.

The unified theory, or as some people just call it, the unification of physics.

Okay, so let's just lay out the stakes right away.

When we look at physics right now, we don't have one single instruction manual for how reality works.

Not at all.

What we have is a collection of really powerful but, well, ultimately limited partial theories.

Right, and our goal today is to really get into what's stopping us from putting all those pieces together, and we'll also dive into the revolutionary idea that might solve it, string theory.

That's the plan.

I mean, these partial theories are incredibly successful, but each one only describes a pretty limited range of what's happening.

And they kind of ignore the other effects, right?

Exactly.

You can, say, calculate how chemicals react using quantum mechanics without ever having to think about gravity pulling on a planet.

They operate in different worlds.

So on one side, we have general relativity, that's our theory for gravity.

It governs everything on the huge cosmic scales, planets, stars, black holes, the whole curvature of spacetime.

And then on the other side, at the incredibly small quantum level, we have totally separate theories for the other three fundamental forces.

The weak, the strong, and the electromagnetic forces.

Right, and those three are often combined pretty successfully into what we call grand unified theories, or GUTs.

And these GUTs are great at what they do.

They describe how particles in an atom's nucleus interact.

They're fantastic, but, and this is the absolute crucial failure point, they just completely leave out gravity.

So the ultimate answer is still missing.

And the central defining problem, the thing that has stumped, I mean, the greatest minds for a century, is that general relativity, our theory of gravity, is what's called a classical theory.

A classical theory.

It assumes that spacetime is smooth and continuous and predictable.

It just doesn't have any concept of the uncertainty principle.

Which is the quantum role that says you can't know both the exact position and the exact momentum of a particle at the same time.

But the other theories,

the GUTs, the ones that run the strong, weak, and electromagnetic forces, they depend on quantum mechanics and that uncertainty principle in a really essential way.

They're all about discrete packets of energy, quanta, not smoothness.

So you're trying to merge a theory of smooth, continuous reality with theories that are all about discrete, probabilistic little packets.

Precisely.

And they just clash.

Fundamentally, when you try to apply them to the same place at the same time, it all falls apart.

So the one necessary condition for any successful complete unified theory is to incorporate the uncertainty principle from the very beginning.

If it doesn't, it's just a non -starter.

A total non -starter.

Before we get into the mathematical train wreck that this clash creates, it's probably worth pointing out that the history of physics is just littered with these, what do you call them, false dawns?

Oh, absolutely.

It's a recurring pattern.

Moments where brilliant people were completely convinced they were just about to solve everything.

And then the universe proves them wrong.

Every time.

And the most famous example of a physicist who dedicated his life to this and, well, failed is, of course, Albert Einstein.

He spent his final decades on this search.

But he was sort of working with two hands tied behind his back, wasn't he?

He was.

For one thing, when he was deep in this work, in the 20s and 30s, we knew almost nothing about the nuclear forces, the strong and weak forces.

You can't unify things you don't even know exist.

That's a huge practical problem.

Yeah.

But the real issue, the sort of tragedy of it, was his philosophical position.

Einstein, even though he was crucial to the start of quantum mechanics.

He never really believed in it.

He refused to believe in the uncertainty principle.

He couldn't accept the randomness it implied about the universe.

That famous line, God does not play dice with the universe.

Exactly.

He was rejecting the one framework that any modern unified theory must use.

He was stuck on this continuous deterministic view of reality.

Which meant his whole approach was really doomed from the start.

It was.

Every experiment since has just confirmed that quantum mechanics is fundamental.

So his unified field theory was built on a flawed premise.

But that level of confidence wasn't just limited to him.

Even the people who did accept the quantum world had moments of, well, hubris.

Oh, for sure.

You mentioned false dawns.

I mean, even before we really understood the atom, some physicists thought everything could be explained by properties of continuous matter.

Like elasticity or how heat moves through a solid.

And then the discovery of the atom and specifically the uncertainty principle just blew that whole idea out of the water.

It showed matter was anything but continuous and smooth at the small scales.

And that leads to my favorite story.

That moment in 1928 after Paul Dirac published his famous equation for the electron.

Ah, yes.

Max Born.

Yeah.

One of the giants of quantum theory.

He told visitors at Gettungen University that physics as a field would basically be over in six months.

And you can understand why.

It wasn't arrogance, really.

It was just pure excitement.

Dirac's equation was so beautiful, so mathematically elegant.

And it worked perfectly for the electron.

The thinking was, OK, we've got the electron.

The only other particle we know about is the proton.

Find an equation for that and we're done.

The job's finished.

Theoretical physics is complete.

And then almost immediately that idea gets, as they say, knocked on the head by the discovery of the neutron.

And with it, the realization of just how complex the nuclear forces really are.

It's such a humbling story.

Just when you think you figured it all out, the universe shows you a whole new level of complexity.

And that brings us right back to the great obstacle, the reason we need a completely new idea, something that breaks away from general relativity.

We have to look at what happens when you apply the uncertainty principle to space itself.

OK, so this is where the math just completely goes off the rails.

What happens physically when you say that even empty space has to obey the uncertainty principle?

Well, the principle is really about energy and time.

Heisenberg's idea means that even in the shortest possible moment, you can't have perfect zero energy, not even in the total vacuum.

Energy has to fluctuate.

And those fluctuations show up as what?

They show up as a constant furious blizzard of creation and annihilation, fleeting virtual particle and antiparticle pairs.

They just pop into existence, borrow a bit of energy for an impossibly short time, and then they destroy each other.

It's a quantum foam, a constant boiling energy soup everywhere.

All the time.

But here's the problem.

When you try to calculate the total energy in that foam, when you sum up all those possible fluctuations, you get a catastrophic result.

You get literal mathematical infinity, not just a big number, an infinite amount of energy.

And Einstein's most famous equation tells us that energy and mass are the same thing.

And mass creates gravity.

So infinite energy means an infinite gravitational attraction.

And according to general relativity, an infinite pole would cause space time to just curve up on itself instantly.

The theory predicts the universe would shrink down to an infinitely small point.

But clearly we're sitting here.

The universe is huge.

It's expanding.

It is definitely not an infinitely small point.

So we've reached a complete theoretical breakdown.

The rules we use for gravity and the rules we use for everything else are just mutually incompatible.

When you combine them, they make a prediction that is flatly obviously wrong.

That infinite pole is the brick wall that forced physicists to look for something completely radical.

What's so frustrating about that is that physicists already had this, well, this very clever, if a bit sketchy, way of dealing with infinities in their other theories.

They did.

It's a technique called renormalization.

And this was the brilliant but maybe desperate hack that let physics move forward.

It was.

It's used incredibly successfully in theories like quantum electrodynamics or QED, which describes how light and matter interact.

Okay, so how does this hack actually work?

How do you subtract infinity from infinity and get a number that actually makes sense?

Okay, let's try an analogy.

Imagine you're trying to calculate the mass of an electron.

Your basic theory gives you its bare mass.

But then you have to add in the effects of that quantum foam we just talked about, all the virtual particles buzzing around it.

And when you calculate the effect of that foam.

You get an infinite value.

So your prediction is the electron's bare mass plus infinity,

which is useless.

Right, because you can go into a lab and measure the electron's mass and it's a very specific finite number.

So renormalization says this.

Look, the real physical mass you measure in the lab already includes the effects of that infinite foam.

So what you do is you go back to your theory and you adjust the initial bare mass and the force strengths by an infinite amount.

You're subtracting an infinity.

You're specifically choosing an infinite negative value to perfectly cancel out the infinite positive value you calculated.

That just sounds, it sounds like you're cooking the books.

You have an infinitely broken ruler.

You subtract an infinite number of imaginary inches.

And somehow you measure a foot and it's exactly 12 inches.

You've just forced the answer.

That's a great way to put it.

And mathematically, it is dubious.

Yeah.

But it works,

it's consistent, and the predictions it makes agree with experiments to an absolutely astonishing degree of accuracy.

We're talking nine or ten decimal places.

It's a massive technical success.

But there has to be a cost, right?

Especially if you're looking for a theory of everything.

What's the hidden price of this trick?

The price is predictive power.

If you subtract infinity from infinity, that finite number you're left with, it's arbitrary.

You didn't derive it from the theory.

So the fundamental numbers that define our universe, the exact mass of an electron, the strength of the electromagnetic force, the theory can't predict them.

No.

You have to go out and measure them and then plug them into the equations by hand.

The standard model, which is our best current theory for three of the forces,

has over 20 of these numbers that just have to be put in manually.

A real theory of everything should be able to predict all of those numbers from first principles.

It should.

And renormalization just gives up on that ideal.

Which brings us back to gravity.

Why couldn't we just use this incredibly successful, a flawed trick on general relativity?

Why is gravity different?

It's just too rigid.

In those other theories, you had enough knobs to turn, enough constants you could adjust to cancel out all the different kinds of infinities that popped up.

But general relativity is much more restrictive.

Far more.

When you try to quantize it, you only really have two quantities you can adjust.

The strength of gravity itself and something called the cosmological constant.

And just adjusting two things isn't enough.

It's not nearly enough to cancel out all the quantum gravity infinities that appear.

The theory still predicts that things we can go out and measure, like the actual curvature of spacetime, are infinite.

We know they're not.

So renormalization just fails to save it.

Which forced a radical pivot.

And in 1976, we get the first big attempt at that pivot.

Something called supergravity.

Supergravity was a beautiful idea.

The thinking was, OK, we can't fix general relativity as it is, so let's make it more complex, more symmetrical.

So general relativity says the gravitational force is carried by a particle with spin 2, the graviton.

Right.

Supergravity said, let's add a whole family of new particles to go along with it.

Particles with spin 32, spin 1, spin 12, and spin zero.

And the really clever idea was to say all of these particles were just different faces of one single super particle.

Exactly.

And they had a very specific plan for those infinities.

The theory was engineered so that the virtual particles with spin 12 and 32 would have mathematically negative energy.

And that negative energy would cancel out the positive energy from the other virtual particles, like the graviton.

It was a built -in cancellation mechanism.

No more arbitrary subtraction.

The symmetry of the theory was supposed to do all the work.

So what was the problem?

It sounds perfect.

The problem was proving it.

The theory symmetry meant a lot of infinities had to cancel.

But proving that all of them canceled perfectly?

Well, that required calculations that were just astronomically difficult.

And this is where it stops being a physics problem and becomes a human problem.

What was the estimate for actually doing the math?

The estimates were just staggering.

It was believed that for one physicist, even with a computer, it would take at least four years of nonstop, highly complex work just to check if the theory was even mathematically sound.

Four years.

And the chance of making a mistake in a four -year -long calculation is...

Practically 100%.

And because it was so complex, there was no way for anyone else to check your work without doing the whole four -year calculation themselves.

And if they got a different answer, who's right?

Exactly.

It was an insurmountable hurdle.

This beautiful, elegant theory failed not because it was wrong, but because we were physically incapable of proving it was right.

So physicists had to move on.

They needed a totally new idea, one that just avoided these calculations altogether.

And that's what paved the way for the string revolution.

And that pivot leads us to maybe the most famous and most sci -fi sounding idea in modern physics,

string theories.

This really took off around 1984, and it completely changed what we think the universe is made of.

It's a fundamental shift in perspective.

I mean, in standard particle physics, everything, electrons, quarks, is treated as a point,

a zero -dimensional dot in space.

String theory says, no, the most basic objects are not points.

They're one -dimensional structures.

Infinitely thin strings.

Oh.

Or little lubes of string.

They have length, but no other dimension.

And that one change completely alters how you visualize their history, their path through time.

It does.

A point particle's journey through space -time is a one -dimensional line.

We call it a world line.

But if a string moves through time, it traces out a two -dimensional surface.

The world sheet.

Right.

And you can picture it.

If you have a closed loop of string, as it moves through time, its world sheet looks like a tube or a cylinder.

If you slice that tube at any point, you see the loop at that one moment in time.

Now, in the old point particle theories,

interactions happen at a single point, a collision.

But what about strings?

This is where the real genius of the theory comes in.

All interactions are just described by the geometry of these world sheets.

There are no more singular points where things suddenly happen.

So what does an interaction look like?

The classic analogy is a pair of trousers.

Imagine two strings coming together to form one.

They're two world sheet tubes just smoothly merged together.

It looks just like the two legs of a pair of trousers joining at the waist.

I see.

It's a smooth merger, not a hard collision.

And I assume a string splitting apart looks like the reverse.

Exactly.

Yeah.

And the things we use to call particles, an electron, a photon, a graviton, are now just different ways for the string to vibrate.

There are different waves or vibrational modes traveling down the string.

So it's like a violin string.

You pluck it one way, you get one note, you pluck it another way, you get a different note.

That's the perfect analogy.

One vibrational pattern on the fundamental string shows up to us as an electron.

A different pattern is a quark.

Another is a graviton.

They're all just different notes being played by the same underlying object.

The source material used a great analogy for gravity.

The force between the Earth and the Sun modeled as plumbing.

The H -shaped pipe.

That's a great way to visualize the world sheet of an interaction.

You have the world sheet of the Earth particle and the Sun particle forming the two vertical bars of the H.

And the horizontal bar connecting them.

That's the world sheet of the graviton, the particle carrying the force of gravity as it travels between them.

It's all one smooth, continuous surface.

And that smoothness is the key to solving the infinity problem.

It is.

The infinities in the old theories came from those singular point -like interactions.

String theory gets rid of the points.

It replaces them with these smooth, extended world sheets.

And by removing the source of the breakdown, you remove the breakdown itself.

But string theory wasn't originally designed to be a theory of gravity, was it?

Not at all.

It was invented back in the late 60s to try and describe the strong nuclear force.

And to do that, the strings needed to have a pretty low tension, only about 10 tons.

Then in 1974, Joel Scherk and John Schwartz made a game -changing discovery.

They realized the math of string theory could describe gravity.

But there was a catch.

For it to work for gravity, the string tension had to be enormous.

Not 10 tons, but something like 10 to the power of 39 tons.

That's an incomprehensible number.

The strings are unbelievably stiff.

And that immense tension is why we don't see them.

It means the strings are incredibly tiny and their vibrations correspond to enormous energies.

So the predictions of string theory and general relativity would be basically identical, except at the tiniest possible scales.

Exactly.

The differences would only show up at the Planck scale.

Distances smaller than 10 to the minus 33 centimeters.

I can't even picture how small that is.

Nobody can.

It's a scale so small that if you blew up an atom to be the size of the entire observable universe, the Planck length would be about the height of a tree.

The strings are confined to this impossibly tiny domain.

So why did this idea, which was initially rejected, have this massive revival in 1984?

It was a perfect storm.

On one hand, supergravity research was completely stalled because of those impossible calculations.

And on the other, a huge new discovery was made.

Schwartz and Mike Green.

They showed that string theory might naturally explain a really deep mystery of particle physics.

Why some particles have a kind of built -in left -handedness.

That gave it a connection to real observed data that supergravity just didn't have.

It did.

And the field just exploded.

It led to the discovery that there were five different consistent string theories.

And one of them, called the heterotic string, seemed especially promising for explaining the actual particles we see in the standard model.

Then what about the infinities?

Well, while you still get infinities in the calculations,

the belief, the strong hypothesis, is that the theory's structure and symmetry forces them all to cancel out perfectly.

The smooth geometry of the world sheet is thought to guarantee it without needing an impossible four -year proof.

Okay, so let's say the infinities do cancel out.

String theory still leaves us with what is probably its most famous,

and, well, its most bizarre challenge,

the need for extra dimensions.

This is the biggest conceptual hurdle, for sure.

For the math of string theory to work, for it to be self -consistent, it seems to demand that space -time isn't four -dimensional.

It has to be either 10 or 26 dimensions, three of space and one of time, plus a bunch of others.

10 or 26, we can barely get our heads around four.

So where are they?

Where are all these other dimensions hiding?

The standard sci -fi idea of a higher dimension is as a shortcut, right?

If you're on a two -dimensional sheet of paper, you have to travel across the surface.

But with a third dimension, you could just fold the paper and jump straight across.

That's the idea.

But since we clearly can't do that, the proposed solution is that the other dimensions are curled up.

We only see the four big expanded ones because the others, the extra six or 22, are curled up into an impossibly small, compact space.

And by impossibly small, we're talking about the Planck scale again.

We're talking about a space that's about a million, million, million, million, millionth of an inch across.

They're so tiny, we just don't experience them.

We move through the four big dimensions, which are, on our scale, flat.

The famous analogy for this is an orange, right?

It's a perfect way to think about it.

If you look at an orange from across the room, it looks like a smooth two -dimensional circle.

But if you get really, really close, you see its skin is actually very curved and wrinkled and has all these little pits in it.

So our four dimensions are the smooth surface we see from far away.

And those little pits and wrinkles you only see up close.

Those are the extra curled up dimensions.

So sadly for space travelers, you can't use them as shortcuts.

They're just too small.

Much too small.

But this raises an even deeper question.

If all the dimensions were curled up and tiny in the early universe,

why did three space dimensions and one time dimension flatten out and expand while all the others stayed small?

This is where we have to bring in a different kind of reasoning, isn't it?

The anthropic principle.

We do.

And it's not really a physical law.

It's more of a selection principle, an observation.

It basically says that we will, by definition, only ever find ourselves in a region of the universe with laws that allow for our own existence.

Our very existence filters the kind of universe we can possibly observe.

Let's go through those constraints because they're amazing.

They're incredibly strict.

Take the number of spatial dimensions.

What if there were only two?

Why is complex life impossible in a 2D world like Flatland?

Well, for one, things couldn't pass each other easily.

But the killer is anatomy.

Imagine a 2D creature needs a digestive tract, a tube that runs all the way through its body.

That tube would literally split the creature into two separate pieces.

It would just fall apart.

You can't have a complex integrated body.

And what about things like a circulatory system or a nervous system?

Impossible.

The pathways would have to cross, which you can't do in two dimensions.

So 2D space is just too restrictive for complex life.

Okay, so what about the other way?

What if we had more than three spatial dimensions?

Say four.

It seems like more room would be better.

It's actually even worse.

It leads to total instability.

In our three dimensions, forces like gravity get weaker by the square of the distance.

Double the distance, the force is one quarter as strong.

And in four spatial dimensions?

Gravity would get weaker much, much faster by the cube of the distance or even more.

And that makes stable orbits impossible.

What do you mean?

Any tiny nudge to the Earth's orbit from another planet or anything, and it would just wobble.

It would either spiral straight into the sun to be incinerated or it would fly off into the cold of deep space.

You couldn't have a planet stay in a stable, habitable zone for billions of years.

And it's not just the planets.

The stars themselves would be unstable.

Exactly.

Our sun exists in this delicate balance between the inward crush of gravity and the outward pressure from fusion.

In a higher dimensional universe, that balance is destroyed.

The sun would either collapse into a black hole or just fly apart.

And it even gets down to the atomic level.

It does.

The electrical forces that hold atoms together behave just like gravity.

In four or more spatial dimensions, electrons would either just fly away from the nucleus or spiral into it almost instantly.

So you couldn't have stable matter.

Forget chemistry.

You couldn't even have atoms.

The conclusion is just shockingly precise.

For a life like us to exist, you need exactly three spatial dimensions and one time dimension to be big and flat.

And what string theory has to do is allow for that possibility.

It has to allow for universes where the other dimensions stay curled up.

And it seems that it does.

The anthropic principle just says we're bound to live in one of them.

So we've gone from supergravity's failure to the rise of strings and seen how our own existence seems to demand a certain number of dimensions.

But even a string theory is the leading candidate.

There are still some major hurdles to clear.

Oh, absolutely.

The two biggest are, first, proving for certain that the theory is finite, that all those infinities really do cancel out.

And second, getting more specific.

What do you mean by specific?

Well, we need to figure out exactly how to match the specific vibrational patterns on the string to the very specific family of particles we see in our universe.

The exact masses and charges of the quarks, the leptons, and so on.

So there's still a lot of work to do, but this brings up a bigger, more philosophical question.

Can an ultimate theory even exist or are we just chasing a moving target forever?

Right.

And you can really frame the whole search in terms of three possibilities.

Possibility one, a complete unified theory exists.

It's unique, it's self -consistent, and we will find it.

Possibility two, there is no final theory.

There's just an endless sequence of better and better theories.

Every time we build a bigger particle accelerator, we find new stuff that forces us to refine our current theory.

And that just goes on forever.

Which, to be fair, has been the pattern so far in history.

And possibility three?

Possibility three is that there is no theory at all.

That events are fundamentally random and arbitrary.

But quantum mechanics kind of takes care of that one, doesn't it?

In a way, yes.

The uncertainty principle already builds in a fundamental level of randomness.

So science has just redefined its goal.

We're trying to find laws that let us predict events up to the limit set by that principle.

We predict the probabilities.

So possibility three is more or less off the table.

So it's a final theory versus an infinite sequence of theories.

Given the history, why would we bet against the infinite sequence?

Why should this time be different?

Because of gravity.

Gravity itself seems to put a final ceiling on that sequence.

There's a physical limit called the Planck energy.

The Planck energy.

Okay, explain why this number, 10 to the 19 GV, acts as a barrier.

It's an almost unimaginable amount of energy.

If you could ever concentrate that much energy onto a single particle, something remarkable would happen.

Because energy is equivalent to mass,

that particle would become so dense it would collapse under its own gravity and form a tiny black hole.

And once it becomes a black hole, it's gone.

It effectively cuts itself off from the rest of the universe.

You can't use it to probe some new, even higher energy physics.

So if your infinite sequence of theories requires testing things at higher and higher energies, the Planck energy is a fundamental wall.

You can't go past it.

That's incredible.

The laws of physics themselves seem to prevent the need for an infinite number of laws.

It suggests a final theory must exist.

The practical problem, of course, is that the Planck energy is so far beyond what we can create.

The Large Hadron Collider gets particles to about one GV.

And the Planck energy is 10 to the 19 GV.

To build an accelerator to reach that energy, you'd need a machine bigger than our entire solar system.

Which, as the source Riley notes, is unlikely to be funded in the present economic climate.

A bit of an understatement.

So our only real window into these ultimate laws isn't in a lab.

It's the universe itself.

Specifically, the very early universe, when these kinds of energies were common.

The ultimate laws are written into the cosmos.

And if we can decipher them, if we find that final theory, the impact would be, I mean, it would be transformative.

Not just for physics.

For all of human knowledge,

think about how specialized science is now.

Even experts only understand a tiny sliver of their own field.

The knowledge is fragmented, inaccessible.

But we've seen this before.

In the early 20th century, maybe a dozen people in the world really understood general relativity.

And today,

millions of people are familiar with the basic concepts of curved space time.

Tens of thousands of university students work with the math every day.

So if a unified theory is found, even if it's incredibly complex, eventually it will be simplified, digested.

It could be taught in schools.

Everyone could have a basic understanding of the laws that are responsible for their own existence.

And that takes us to the highest philosophical goal.

It brings us back to Einstein's question.

How much choice did God have in constructing the universe?

If the final theory is unique, if it's the only mathematically self -consistent way a universe could be, what does that mean for choice?

It would mean there was little or no choice.

If the theory is unique, and if ideas like the no -boundary proposal for the universe's origin are right, then the universe was logically compelled to be the way it is.

This completely changes the conversation.

For centuries, philosophers asked why the universe exists.

But then science got so technical that many of them stepped back and physicists just focused on what and how.

But if we find a complete theory, and if everyone can understand its basic principles, then for the first time in history, we can all take part in that discussion.

The discussion of why the universe is here at all, it would be the ultimate triumph of human reason.

It really would be.

The ultimate prize.

So we've taken this deep dive from, well, the overconfidence of early physics to the realization that general relativity and quantum mechanics just catastrophically clash.

We saw how that clash leads to infinite energy and how the leap from point particles to one -dimensional strings and the smooth geometry of the world sheet is an attempt to fix that.

And we learned that our own existence, through the anthropic principle, seems to demand that we live in a universe with three large spatial dimensions because life is just impossible otherwise.

And finally, that incredible barrier, the Planck energy, suggests that this whole search isn't a mirage.

It's a finite, reachable goal.

The lasting impact seems clear.

A unified theory isn't just an equation for physicists.

It's the key to letting everyone understand the fundamental rules of existence.

But the ultimate question still hangs there.

If we find it, this one beautiful, complete set of equations,

is that enough?

Do the equations themselves compel a universe into existence or does something else have to come along and breathe fire into the equations?

And that, that's the boundary between physics and metaphysics.

That's the final question that science, after answering all the what's and how's, has to turn over to all of us.

By finding the answer to why, we would, as the source puts it, know the mind of God.

Thank you for joining us for this deep dive into the ultimate quest for cosmic understanding.