Why is there — Okay. Okay. (Laughter)

This is a cosmic mystery. Be solemn.

Why is there a world, why are we in it,

and why is there something rather than nothing at all?

I mean, this is the super ultimate "why" question?

So I'm going to talk about the mystery of existence,

the puzzle of existence,

where we are now in addressing it,

and why you should care,

and I hope you do care.

The philosopher Arthur Schopenhauer said that

those who don't wonder about the contingency of their existence,

of the contingency of the world's existence,

are mentally deficient.

That's a little harsh, but still. (Laughter)

So this has been called the most sublime

and awesome mystery,

the deepest and most far-reaching question

man can pose.

It's obsessed great thinkers.

Ludwig Wittgenstein, perhaps the greatest

philosopher of the 20th century,

was astonished that there should be a world at all.

He wrote in his "Tractatus," Proposition 4.66,

"It is not how things are in the world

that is the mystical,

it's that the world exists."

And if you don't like taking your epigrams

from a philosopher, try a scientist.

John Archibald Wheeler, one of the great physicists

of the 20th century,

the teacher of Richard Feynman,

the coiner of the term "black hole,"

he said, "I want to know

how come the quantum,

how come the universe, how come existence?"

And my friend Martin Amis —

sorry that I'll be doing a lot of name-dropping in this talk,

so get used to it —

my dear friend Martin Amis once said

that we're about five Einsteins away from answering

the mystery of where the universe came from.

And I've no doubt there are five Einsteins

in the audience tonight.

Any Einsteins? Show of hands? No? No? No?

No Einsteins? Okay.

So this question, why is there something rather than nothing,

this sublime question, was posed rather late

in intellectual history.

It was towards the end of the 17th century,

the philosopher Leibniz who asked it,

a very smart guy, Leibniz,

who invented the calculus

independently of Isaac Newton, at about the same time,

but for Leibniz, who asked why is there something rather than nothing,

this was not a great mystery.

He either was or pretended to be

an Orthodox Christian in his metaphysical outlook,

and he said it's obvious why the world exists:

because God created it.

And God created, indeed, out of nothing at all.

That's how powerful God is.

He doesn't need any preexisting materials to fashion a world out of.

He can make it out of sheer nothingness,

creation ex nihilo.

And by the way, this is what

most Americans today believe.

There is no mystery of existence for them.

God made it.

So let's put this in an equation.

I don't have any slides so I'm going to mime my visuals,

so use your imaginations.

So it's God + nothing = the world.

Okay? Now that's the equation.

And so maybe you don't believe in God.

Maybe you're a scientific atheist

or an unscientific atheist, and you don't believe in God,

and you're not happy with it.

By the way, even if we have this equation,

God + nothing = the world,

there's already a problem:

Why does God exist?

God doesn't exist by logic alone

unless you believe the ontological argument,

and I hope you don't, because it's not a good argument.

So it's conceivable, if God were to exist,

he might wonder, I'm eternal, I'm all-powerful,

but where did I come from?

(Laughter)

Whence then am I?

God speaks in a more formal English.

(Laughter)

And so one theory is that God was so bored with

pondering the puzzle of His own existence

that He created the world just to distract himself.

But anyway, let's forget about God.

Take God out of the equation: We have

________ + nothing = the world.

Now, if you're a Buddhist,

you might want to stop right there,

because essentially what you've got is

nothing = the world,

and by symmetry of identity, that means

the world = nothing. Okay?

And to a Buddhist, the world is just a whole lot of nothing.

It's just a big cosmic vacuity.

And we think there's a lot of something out there

but that's because we're enslaved by our desires.

If we let our desires melt away,

we'll see the world for what it truly is,

a vacuity, nothingness,

and we'll slip into this happy state of nirvana

which has been defined as having

just enough life to enjoy being dead. (Laughter)

So that's the Buddhist thinking.

But I'm a Westerner, and I'm still concerned

with the puzzle of existence, so I've got

________ + —

this is going to get serious in a minute, so —

________ + nothing = the world.

What are we going to put in that blank?

Well, how about science?

Science is our best guide to the nature of reality,

and the most fundamental science is physics.

That tells us what naked reality really is,

that reveals what I call TAUFOTU,

the True And Ultimate Furniture Of The Universe.

So maybe physics can fill this blank,

and indeed, since about the late 1960s or around 1970,

physicists have purported to give

a purely scientific explanation of how

a universe like ours could have popped into existence

out of sheer nothingness,

a quantum fluctuation out of the void.

Stephen Hawking is one of these physicists,

more recently Alex Vilenkin,

and the whole thing has been popularized

by another very fine physicist and friend of mine,

Lawrence Krauss, who wrote a book called

"A Universe from Nothing,"

and Lawrence thinks that he's given —

he's a militant atheist, by the way,

so he's gotten God out of the picture.

The laws of quantum field theory,

the state-of-the-art physics, can show how

out of sheer nothingness,

no space, no time, no matter, nothing,

a little nugget of false vacuum

can fluctuate into existence,

and then, by the miracle of inflation,

blow up into this huge and variegated cosmos

we see around us.

Okay, this is a really ingenious scenario.

It's very speculative. It's fascinating.

But I've got a big problem with it,

and the problem is this:

It's a pseudo-religious point of view.

Now, Lawrence thinks he's an atheist,

but he's still in thrall to a religious worldview.

He sees physical laws as being like divine commands.

The laws of quantum field theory for him

are like fiat lux, "Let there be light."

The laws have some sort of ontological power or clout

that they can form the abyss,

that it's pregnant with being.

They can call a world into existence out of nothing.

But that's a very primitive view of what

a physical law is, right?

We know that physical laws are actually

generalized descriptions of patterns and regularities

in the world.

They don't exist outside the world.

They don't have any ontic cloud of their own.

They can't call a world into existence

out of nothingness.

That's a very primitive view

of what a scientific law is.

And if you don't believe me on this,

listen to Stephen Hawking,

who himself put forward a model of the cosmos

that was self-contained,

didn't require any outside cause, any creator,

and after proposing this,

Hawking admitted that he was still puzzled.

He said, this model is just equations.

What breathes fire into the equations

and creates a world for them to describe?

He was puzzled by this,

so equations themselves can't do the magic,

can't resolve the puzzle of existence.

And besides, even if the laws could do that,

why this set of laws?

Why quantum field theory that describes

a universe with a certain number of forces

and particles and so forth?

Why not a completely different set of laws?

There are many, many mathematically consistent sets of laws.

Why not no laws at all? Why not sheer nothingness?

So this is a problem, believe it or not,

that reflective physicists really think a lot about,

and at this point they tend to go metaphysical,

say, well, maybe the set of laws

that describes our universe,

it's just one set of laws

and it describes one part of reality,

but maybe every consistent set of laws

describes another part of reality,

and in fact all possible physical worlds

really exist, they're all out there.

We just see a little tiny part of reality

that's described by the laws of quantum field theory,

but there are many, many other worlds,

parts of reality that are described

by vastly different theories

that are different from ours in ways we can't imagine,

that are inconceivably exotic.

Steven Weinberg, the father

of the standard model of particle physics,

has actually flirted with this idea himself,

that all possible realities actually exist.

Also, a younger physicist, Max Tegmark,

who believes that all mathematical structures exist,

and mathematical existence is the same thing

as physical existence,

so we have this vastly rich multiverse

that encompasses every logical possibility.

Now, in taking this metaphysical way out,

these physicists and also philosophers are actually

reaching back to a very old idea

that goes back to Plato.

It's the principle of plenitude or fecundity,

or the great chain of being,

that reality is actually as full as possible.

It's as far removed from nothingness

as it could possibly be.

So we have these two extremes now.

We have sheer nothingness on one side,

and we have this vision of a reality

that encompasses every conceivable world

at the other extreme: the fullest possible reality,

nothingness, the simplest possible reality.

Now what's in between these two extremes?

There are all kinds of intermediate realities

that include some things and leave out others.

So one of these intermediate realities

is, say, the most mathematically elegant reality,

that leaves out the inelegant bits,

the ugly asymmetries and so forth.

Now, there are some physicists who will tell you

that we're actually living in the most elegant reality.

I think that Brian Greene is in the audience,

and he has written a book called "The Elegant Universe."

He claims that the universe we live in mathematically

is very elegant.

Don't believe him. (Laughter)

It's a pious hope, I wish it were true,

but I think the other day he admitted to me

it's really an ugly universe.

It's stupidly constructed,