An Interview With Sherrilyn Roush
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 Rice University, she holds a double B.S. in math and philosophy, and a Ph.D. in philosophy from Harvard. This soft-spoken woman (whose website photo shows a pretty gamine with sunglasses propped on her head and a multicolored blouse more suited to an artist gamboling through Europe than a professor in Texas) takes on the philosophy of science, epistemology, and metaphysics. She is the recipient of a Center for the Study of Cultures Fellowship to facilitate work on her project Knowing in the World. In particular, she has extensively analyzed the fallacies and strengths of anthropic visions of the universe. Roush is unsparing and extraordinarily intelligent on cosmology. Physicists, open the golden doors, usher her in, and give her a cup of home-brewed tea!
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.
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: The many-universe hypothesis you get from the SAP is 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. But you haven’t thereby said why any of those exist. 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 all those universes exist and thereby why the universe is habitable. That’s a story and a physical theory. Another theory that gave a physical mechanism for generating many universes was Andre Linde’s inflationary cosmology, which gave us a physical explanation for how the universe came to have several of the key features it now has. These views are different than SAP many-world views that simply posit the mere existence of many universes because these views are actually doing physics, giving physical reasons.
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 given in the SAP case why they should exist, and the theory definitely violates Ockham’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 such theories directly. 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 SAP version of a 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 blankly 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. That realization, that our best evidence didn’t decide the matter, gave him an opening to freely develop the alternative view that really the earth was 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. It’s a brilliant idealization. But in quantum mechanics, and in cosmology, people will have to start thinking differently.
Q: You caution that naive self-love is as dangerous as naive self-loathing, which is what happens when we take Copernicus’ idea to the extreme. Infact, 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? Into nothing? Into a penetrating sense of his nothingness?”
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 much of 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 who is a physical being. 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.