At the Temple of
Physics With Sherrilyn Roush
By Jill Neimark
It’s a
rare philosopher who comes knocking at the gilded doors of the temple of
physics: philosophers aren’t often
invited in, even for a polite afternoon tea.
Physics, like all of science, may recognize that it shares much with
philosophy—both fields center around what we
know about the world, and both would be bankrupt without the imaginative leap,
the bold new conjecture. But even so,
physicists are our culture’s high priests of big science, the kind where
big bang means not only atomic bombs but a theory of the beginning of the
universe. They don’t need to spoil
their fun with philosophy, especially since most philosophers can’t even talk
basic math with them.
But Sherrilyn Roush can and does. Assistant Professor of Philosophy at
This is the
third in a series where we ask deep thinkers about their views of cosmology and
the universe. The first was with
theoretical physicist Lee Smolin, and the second with
theoretical biologist Stuart Kauffman.
—Jill
Neimark
Q: Physics needs philosophers and critics like yourself, people thinking about how science imagines and
envisions the world, and how that imagining influences the future of
research. And yet it still tends to snub
philosophers.
A: That’s true, and I was much more
ambitious when I was younger about getting them to listen to me.
Q: Why don’t they?
A: A lot of the field’s prestige comes
from the cultural power it got during the cold war, after the atomic bomb. That
era in American physics was very pragmatic, partly because of individuals like
Richard Feynman.
He was very, very smart and a clear thinker, but he also had a disdain
for anything philosophical. He was the
leader of an era in which philosophical understanding of what you were doing
was not highly valued. And philosophy
was not going to be rewarded with defense contracts. Also, American culture tends to be pragmatic
rather than philosophical.
Q: Still,
it’s amazing that so many of us look to physicists now to tell us whether
or not God exists. How did that happen?
A: It’s extraordinary,
the implication that people who knew how to make bombs would be experts on God. I don’t think religion should be in the
business of explaining the physical world, and I don’t think science
should tell us how to live our lives or create community and spiritual
experience.
Q: Let’s discuss the place where physics
encounters God: the anthropic
principle—the recognition that the laws of the universe seem fine-tuned,
and that this fine-tuning may have a purpose.
You make a powerful case against the so called “strong”
version of the anthropic principle (SAP), and just as
powerful a case for what you see as the properly interpreted version of the
“weak” anthropic principle (WAP).
A: First, I should say I don’t like those
names, weak and strong, because they imply that the weak is just a version of
the strong that doesn’t claim quite as much. And that’s not true,
they’re actually totally opposite in what they’re claiming. The strong is speculative, and trying to
infer a positive conclusion from the evidence, whereas the weak is skeptical
and questions the quality of evidence.
I’d rather call the strong anthropic
principle metaphysical, and the weak epistemic—which means it simply has
to do with knowledge.
Q: You’ve said that the claims the SAP make
actually betray the traditional goals of physics. In one essay you write: “Physics prides itself on seeking and
offering objective explanations of natural phenomena. It tries to say how things are, and why they
are as they are, in the physical world that exists independently of
us…The scale of a human being’s ordinary concerns—the world
of middle-sized dry goods, as J.L. Austin called it—does not restrict the
interest of the physicist…Above all, the goal of physics is not to
describe the world in such as a way as to make human beings feel they are
significant to it.” And yet the SAP
does just that.
A: There’s a central flaw with the SAP,
and that’s the clear sense in which appealing to the ‘God made
it’ hypothesis looks like it’s appealing to something that is very
comforting to human beings. In addition,
the hypothesis is teleological, and physics has traditionally avoided that kind
of thinking.
Q: One version of the strong principle is the
many-worlds hypothesis. There are
different versions of this hypothesis floating around, but all of them posit an
endless number of possible universes—thus explaining the mystery of
seemingly fine-tuned laws by saying that there are so many universes, this one
just happens to have laws suited to life.
A: It’s a cheat. The attempt of such hypotheses is to remove
the question of why this one is the way it is, so you postulate that all
possibilities exist, and therefore this one is not special. However, there are
some versions of the many-worlds hypothesis that actually explain why and how
these worlds might exist. When Lee Smolin proposed that baby universes were born out of black
holes, he gave universes heritable traits, and suggested that concentration of
black holes is correlated with concentration of galaxies, stars, and the
possibility of life—giving us an explanation of why the universe is
habitable. That’s a story and a
physical theory. Another reasonable
theory was Andre Linde’s inflationary
cosmology, which gave us a physical explanation for how certain laws became
exponentially large. These views are
different than SAP many-world views that simply posit the mere existence of
many universes.
Q: We tend to think of nature as efficient. It would seem a waste of energy to generate
infinite universes.
A: There’s certainly no physical reason
why they should exist, and the theory definitely violates Occam’s
razor, which says one should not increase, beyond what is necessary, the number
of entities required to explain anything.
Q: I’m always mystified when physicists
who propose many worlds talk as if there are multiple versions of me that
actually exist out there. I haven’t noticed any yet.
A: The convenient thing is that those other
branches, or universes, are not available to us, and so their existence is not measurable. We can’t really test it. However, views like that actually follow from
making philosophical assumptions about the math. Personally, if I were forced
to choose between the SAP’s God-hypothesis or the many-worlds hypothesis, I’d prefer the
God-hypothesis on the grounds of simplicity.
It seems simpler ontologically to call on God to choose the one world
that fits the bill, than to suppose that all of them happened.
Q: Let’s talk about WAP. You see that as reasonable, and also as
strongly within the tradition of Copernicus, but a Copernicus that most of us
are not familiar with. We tend to take
his idea that our place in the universe is not special, and abstract out an
entire credo that pits science against humanity and religion, as a destroyer of
the human need to be special and meaningful.
A: A lot of proponents of the anthropic principle say that it represents a step away from
Copernicus. I think that shows a
misunderstanding about the WAP as well as about Copernicus. The WAP recognizes that our evidence about
the universe is restricted by the conditions necessary for our presence as
observers.
Q: Why do some think it means we’re moving
away from Copernicus?
A: People tend to focus on the part of
Copernicus’ theory where he throws the earth out of the center, and
neglect the part where he makes arguments that the earth moves. And it’s in that part that the more
interesting stuff is happening. When he
argues for his theory, he is taking into account the fact that we are observing
from a particular place, and that place is part of the subject matter that
we’re trying to figure out. We look out and we don’t feel any
motion of the earth. He notices that the
position from which we’re observing doesn’t give us good evidence
about whether the earth is moving or the stars are moving.
Q: As a culture we focused on the part that
says, ‘We’re not special.’ Has that influenced the direction
of our science?
A: Yes.
If you think that one of your chief aims must be to avoid thinking
you’re special, you may ignore the observer. As Copernicus showed, you have to pay
attention to the observer, you have to say, ‘Wait a minute, we’re
looking, and we’re looking from a particular place, and what is the
consequence of that?’
Q: If we understood Copernicus more richly than
we do, how would scientific research have proceeded differently?
A: That’s a very interesting
question. I think it matters most for
our future. Physics has gone a long way
with the idea that we’re not special, and a lot of what the field has
achieved wouldn’t have been possible without that idea. But in quantum mechanics, and in cosmology,
people will have to start thinking differently.
Q: You caution that naïve self-love is as
dangerous as naïve self-loathing, which is what happens when we take
Copernicus’ idea to the extreme.
In fact, you make the astonishing point that this approach actually has
its roots in Christian asceticism.
Who’d think to connect the rationality of Copernicus to Christian
asceticism—at least in popular culture’s understanding of science.
A: I’ve
modified an idea of Nietzsche’s.
He really understood this question, and he felt that science, to the
extent it was following Copernicus, was actually following a form of
Christianity. He wrote, “Has
man’s will to self belittlement not progressed irresistibly since
Copernicus?...He who was, according to his old faith, almost God, a child of
God, since Copernicus…seems to be…slipping faster and faster away
from the center into what?”
Q: So, in
the anthropic tradition, what is WAP really saying?
A: One thing the WAP is saying is the fact that
you’re a product of the universe you’re studying affects your
ability to get knowledge about that universe.
A kind of skepticism comes from being embedded in a certain place with a
certain history. In contrast, the SAP is
actually in competition with the future of physics. Physicists are well aware that fine-tuning is
a problem, and they understand that solving problems like this may lead to the
next big theory. They’ve
understood all along that the standard model of physics wasn’t the final
theory, because it requires tweaking the parameters. Right now the interesting action in physics
is definitely about fine-tuning, and if physics does its job successfully it
will replace the theology with explanation, just as biology replaced design
arguments with natural selection.
Q: I guess you would say to proponents of SAP
what Richard Dawkins said to Michael Behe when he
says things like an eye cannot be fully explained by natural selection: Try
harder.
A: Yes, I’d say exactly the same
thing. If they don’t try harder,
somebody else will, and soon. I
wouldn’t want to build my religious views on something so vulnerable to
disappearing. I recently heard Behe talk, and his argument basically was, ‘I can
point to all these molecular machines nobody has explained by natural
selection.’ I grant that there are
things that are not explained yet, and I also grant the possibility that
natural selection can’t do it alone, but pointing out it hasn’t
been done yet is not an argument. And it
doesn’t lead to interesting science.
Q: What kind
of metaphysics would lead to interesting science?
A: I always
say that one of the reasons God hypotheses are not illuminating from the point
of view of physics is that God is generally not taken to be a physical thing,
so we don’t have to give a physical account of God. But there are theologies in which God is a
physical thing, and it would be interesting to make a theory of physics about
God.
Q: In other words, you could posit God as
consisting of certain properties or laws?
A: No, that would be more like Spinoza, who identified God with physical laws. Most religious people would not be satisfied
with that. But the Mormons, as far as I
understand, have a picture of a personal God.
It would be interesting to see a physics that included God, though I
don’t know of any.
Q: These are deep questions and we’ve been
grappling with them for centuries. Do
you think we’re bringing anything new to the argument these days?
A: Yes, I think that we really are being forced
to think differently because of fine-tuning.
The real lesson to take is that we need to think about the universe in a
way that takes account of the fact that we’re thinking about it. We’re a product of it. This requires a much more integrated
account. And fine-tuning was shocking
enough that physicists have been forced to do this, and to start thinking
differently. To try and construct a
cosmology where the cosmologist is not outside the universe.
