Illustration by Andy Martin
Published: March 23, 2012
Original Link: http://www.nytimes.com/2012/03/25/books/review/a-universe-from-nothing-by-lawrence-m-krauss.html?pagewanted=all
Lawrence M. Krauss, a well-known cosmologist and prolific
popular-science writer, apparently means to announce to the world, in
this new book, that the laws of quantum mechanics have in them the
makings of a thoroughly scientific and adamantly secular explanation of
why there is something rather than nothing. Period. Case closed. End of
story. I kid you not. Look at the subtitle. Look at how Richard Dawkins
sums it up in his afterword: “Even the last remaining trump card of the
theologian, ‘Why is there something rather than nothing?,’ shrivels up
before your eyes as you read these pages. If ‘On the Origin of Species’
was biology’s deadliest blow to supernaturalism, we may come to see ‘A
Universe From Nothing’ as the equivalent from cosmology. The title means
exactly what it says. And what it says is devastating.”
Well, let’s see. There are lots of different sorts of conversations one might want to have about a claim like that: conversations, say, about what it is to explain something, and about what it is to be a law of nature, and about what it is to be a physical thing. But since the space I have is limited, let me put those niceties aside and try to be quick, and crude, and concrete.
Where, for starters, are the laws of quantum mechanics themselves
supposed to have come from? Krauss is more or less upfront, as it turns
out, about not having a clue about that. He acknowledges (albeit in a
parenthesis, and just a few pages before the end of the book) that
everything he has been talking about simply takes the basic principles
of quantum mechanics for granted. “I have no idea if this notion can be
usefully dispensed with,” he writes, “or at least I don’t know of any
productive work in this regard.” And what if he did know of some
productive work in that regard? What if he were in a position to
announce, for instance, that the truth of the quantum-mechanical laws
can be traced back to the fact that the world has some other, deeper
property X? Wouldn’t we still be in a position to ask why X rather than
Y? And is there a last such question? Is there some point at
which the possibility of asking any further such questions somehow
definitively comes to an end? How would that work? What would that be
like?
Never mind. Forget where the laws came from. Have a look instead at what
they say. It happens that ever since the scientific revolution of the
17th century, what physics has given us in the way of candidates for the
fundamental laws of nature have as a general rule simply taken it for
granted that there is, at the bottom of everything, some basic,
elementary, eternally persisting, concrete, physical stuff.
Newton, for example, took that elementary stuff to consist of material
particles. And physicists at the end of the 19th century took that
elementary stuff to consist of both material particles and
electromagnetic fields. And so on. And what the fundamental laws of
nature are about, and all the fundamental laws of nature are about, and all there is
for the fundamental laws of nature to be about, insofar as physics has
ever been able to imagine, is how that elementary stuff is arranged.
The fundamental laws of nature generally take the form of rules
concerning which arrangements of that stuff are physically possible and
which aren’t, or rules connecting the arrangements of that elementary
stuff at later times to its arrangement at earlier times, or something
like that. But the laws have no bearing whatsoever on questions of where
the elementary stuff came from, or of why the world should have
consisted of the particular elementary stuff it does, as opposed to
something else, or to nothing at all.
The fundamental physical laws that Krauss is talking about in “A
Universe From Nothing” — the laws of relativistic quantum field theories
— are no exception to this. The particular, eternally persisting,
elementary physical stuff of the world, according to the standard
presentations of relativistic quantum field theories, consists
(unsurprisingly) of relativistic quantum fields. And the fundamental
laws of this theory take the form of rules concerning which arrangements
of those fields are physically possible and which aren’t, and rules
connecting the arrangements of those fields at later times to their
arrangements at earlier times, and so on — and they have nothing
whatsoever to say on the subject of where those fields came from, or of
why the world should have consisted of the particular kinds of fields it
does, or of why it should have consisted of fields at all, or of why
there should have been a world in the first place. Period. Case closed.
End of story.
What on earth, then, can Krauss have been thinking? Well, there is, as
it happens, an interesting difference between relativistic quantum field
theories and every previous serious candidate for a fundamental
physical theory of the world. Every previous such theory counted
material particles among the concrete, fundamental, eternally persisting
elementary physical stuff of the world — and relativistic quantum field
theories, interestingly and emphatically and unprecedentedly, do not.
According to relativistic quantum field theories, particles are to be
understood, rather, as specific arrangements of the fields. Certain
arrangements of the fields, for instance, correspond to there being 14
particles in the universe, and certain other arrangements correspond to
there being 276 particles, and certain other arrangements correspond to
there being an infinite number of particles, and certain other
arrangements correspond to there being no particles at all. And
those last arrangements are referred to, in the jargon of quantum field
theories, for obvious reasons, as “vacuum” states. Krauss seems to be
thinking that these vacuum states amount to the
relativistic-quantum-field-theoretical version of there not being any physical stuff at all.
And he has an argument — or thinks he does — that the laws of
relativistic quantum field theories entail that vacuum states are
unstable. And that, in a nutshell, is the account he proposes of why
there should be something rather than nothing.
But that’s just not right. Relativistic-quantum-field-theoretical vacuum
states — no less than giraffes or refrigerators or solar systems — are
particular arrangements of elementary physical stuff. The true
relativistic-quantum-field-theoretical equivalent to there not being
any physical stuff at all isn’t this or that particular arrangement of
the fields — what it is (obviously, and ineluctably, and on the
contrary) is the simple absence of the fields! The fact that
some arrangements of fields happen to correspond to the existence of
particles and some don’t is not a whit more mysterious than the fact
that some of the possible arrangements of my fingers happen to
correspond to the existence of a fist and some don’t. And the fact that
particles can pop in and out of existence, over time, as those fields
rearrange themselves, is not a whit more mysterious than the fact that
fists can pop in and out of existence, over time, as my fingers
rearrange themselves. And none of these poppings — if you look at them
aright — amount to anything even remotely in the neighborhood of a
creation from nothing.
Krauss, mind you, has heard this kind of talk before, and it makes him
crazy. A century ago, it seems to him, nobody would have made so much as
a peep about referring to a stretch of space without any material
particles in it as “nothing.” And now that he and his colleagues think
they have a way of showing how everything there is could imaginably have
emerged from a stretch of space like that, the nut cases are moving the
goal posts. He complains that “some philosophers and many theologians
define and redefine ‘nothing’ as not being any of the versions of
nothing that scientists currently describe,” and that “now, I am told by
religious critics that I cannot refer to empty space as ‘nothing,’ but
rather as a ‘quantum vacuum,’ to distinguish it from the philosopher’s
or theologian’s idealized ‘nothing,’ ” and he does a good deal of
railing about “the intellectual bankruptcy of much of theology and some
of modern philosophy.” But all there is to say about this, as far as I
can see, is that Krauss is dead wrong and his religious and
philosophical critics are absolutely right. Who cares what we would or
would not have made a peep about a hundred years ago? We were wrong
a hundred years ago. We know more now. And if what we formerly took for
nothing turns out, on closer examination, to have the makings of
protons and neutrons and tables and chairs and planets and solar systems
and galaxies and universes in it, then it wasn’t nothing, and it couldn’t
have been nothing, in the first place. And the history of science — if
we understand it correctly — gives us no hint of how it might be
possible to imagine otherwise.
And I guess it ought to be mentioned, quite apart from the question of
whether anything Krauss says turns out to be true or false, that the
whole business of approaching the struggle with religion as if it were a
card game, or a horse race, or some kind of battle of wits, just feels
all wrong — or it does, at any rate, to me. When I was growing up, where
I was growing up, there was a critique of religion according to which
religion was cruel, and a lie, and a mechanism of enslavement, and
something full of loathing and contempt for everything essentially
human. Maybe that was true and maybe it wasn’t, but it had to do with
important things — it had to do, that is, with history, and with
suffering, and with the hope of a better world — and it seems like a
pity, and more than a pity, and worse than a pity, with all that in the
back of one’s head, to think that all that gets offered to us now, by
guys like these, in books like this, is the pale, small, silly, nerdy
accusation that religion is, I don’t know, dumb.
