This New York Times op-ed, to be precise. My questions for Paul Davies can be boiled down to these two:
- What kinds of explanations, precisely, are you asking science to deliver to you?
- Just why do you think it is the job of science to provide such explanations?
Let’s back up a little and look at some of what Davies writes in his op-ed:
… science has its own faith-based belief system. All science proceeds on the assumption that nature is ordered in a rational and intelligible way. You couldn’t be a scientist if you thought the universe was a meaningless jumble of odds and ends haphazardly juxtaposed. When physicists probe to a deeper level of subatomic structure, or astronomers extend the reach of their instruments, they expect to encounter additional elegant mathematical order. And so far this faith has been justified.
The most refined expression of the rational intelligibility of the cosmos is found in the laws of physics, the fundamental rules on which nature runs. The laws of gravitation and electromagnetism, the laws that regulate the world within the atom, the laws of motion — all are expressed as tidy mathematical relationships. But where do these laws come from? And why do they have the form that they do?
When I was a student, the laws of physics were regarded as completely off limits. The job of the scientist, we were told, is to discover the laws and apply them, not inquire into their provenance. The laws were treated as “given” — imprinted on the universe like a maker’s mark at the moment of cosmic birth — and fixed forevermore. Therefore, to be a scientist, you had to have faith that the universe is governed by dependable, immutable, absolute, universal, mathematical laws of an unspecified origin. You’ve got to believe that these laws won’t fail, that we won’t wake up tomorrow to find heat flowing from cold to hot, or the speed of light changing by the hour.
Here, Davies makes it sound like being a scientist requires a metaphysical commitment to a certain sort of order and intelligibility within the universe. While many scientists may in fact have such a commitment, I think making it a requirement is too strong. Rather, science seems to depend on a bundle of methodological commitments (about the utility of trying to find stable patterns of behavior, tidy mathematical relations, and so forth). As I wrote in an ancient post on the ancestor of this blog
Of course scientific theories bring some philosophy with them. You think the data we collect today can help us make good predictions about what will happen tomorrow? That reflects a metaphysical commitment you have about what kind of universe you’re living in. And there’s nothing wrong with having that commitment. Indeed, it’s what helps some of us get out of bed in the morning. You want to show me the analysis that shows your results are statistically significant? Fine, but don’t forget that the claim of statistical significance rests on metaphysical commitments about the normal distribution of data in the bit of the world you’re studying. If you didn’t start with some metaphysical hunches, there would be no way to do any science.
Please note that I take hunches — even metaphysical hunches — to be much less binding than commitments.
But, … there is an important distinction between what one takes up as a methodological strategy and what one takes on as a metaphysical commitment…
The deal with science — the thing that makes it different from some “philosophical theories” you might worry about — it that there’s a serious attempt to do the job of describing, explaining, and manipulating the universe with a relatively lean set of metaphysical commitments, and to keep many of the commitments methodological. If you’re in the business of using information from the observables, there are many junctures where the evidence is not going to tell you for certain whether P is true or not-P is true. There has to be a sensible way to deal with, or to bracket, the question of P so that science doesn’t grind to a halt while you wait around for more evidence. Encounter a phenomenon that you’re not sure is explainable in terms of any of the theories or data you have at the ready? You can respond by throwing your hands up and hypothesizing, “A wizard did it!” , or you can dig in and see whether further investigation of the phenomenon will yield an explanation. Sometimes it does, and sometimes it doesn’t. In cases where it does not, science is still driven by a commitment to build an explanation in terms of stuff in the natural world, despite the fact that we may have to reframe our understanding of that natural world in fairly significant ways.
The title of his op-ed notwithstanding (“Taking Science on Faith”), I don’t think Davies’ main concern here is that scientists are blind to the fact that they make certain foundational assumptions in order to get to the business of examining and explaining their phenomena. In part, I don’t think this is what Davies is on about because scientists know that they are making these foundational assumptions. How tightly they hold them, whether they are methodological or metaphysical commitments, seems a side issue to the issue Davies is pressing. He writes:
Over the years I have often asked my physicist colleagues why the laws of physics are what they are. The answers vary from “that’s not a scientific question” to “nobody knows.” The favorite reply is, “There is no reason they are what they are — they just are.” The idea that the laws exist reasonlessly is deeply anti-rational. After all, the very essence of a scientific explanation of some phenomenon is that the world is ordered logically and that there are reasons things are as they are. If one traces these reasons all the way down to the bedrock of reality — the laws of physics — only to find that reason then deserts us, it makes a mockery of science.
Can the mighty edifice of physical order we perceive in the world about us ultimately be rooted in reasonless absurdity? If so, then nature is a fiendishly clever bit of trickery: meaninglessness and absurdity somehow masquerading as ingenious order and rationality.
Can Davies be right that “the very essence of a scientific explanation of some phenomenon is that the world is ordered logically and that there are reasons things are as they are”? This seems rather stronger than, say, pointing out the natural causes for the natural phenomena being explained. At least, Davies seems to be asking for something stronger if he demands reasons why all the laws are as they are, and why all the stuff of the universe turned out as it did, that explain everything — the “bedrock” as well.
Asking for explanations of the level which we currently hold as the bedrock — the “fundamental” level as far as our understanding is concerned — isn’t a problem. Expecting that every level must yield further explanations in terms of another level underneath, else our science has failed and dissolved into absurdity, strikes me as unwarranted. (This over-strong demand, in fact, strikes me as a mockery of science.)
Davies then writes a bunch of stuff about multiverse theory that makes it sound as if physicists are all dyed-in-the-wool Platonists as far as laws of physics are concerned. He writes, for example, that “physicists think of their laws as inhabiting an abstract transcendent realm of perfect mathematical relationships”. Maybe some of them do, but is this a commitment that is built into the edifice of Physics, or is it rather the leaning of individual physicists who work to contribute to that edifice?
If the physicists could weigh in on this, I’d be much obliged. It seems like a suspect claim to me — and I’m coming at it from the point of view of a former physical chemist who then studied metaphysics. “Laws of nature” (or of physics, if you prefer) strike me as something more like a set of generalizations about what the stuff of reality does (or might do with certain probability) in particular conditions.
Anyway, whatever sort of things the laws of nature might be, what kind of answer does Davies want to the question of why the laws are what they are? If somehow physicists worked out that the properties of the most fundamental stuff, plus the initial conditions of that stuff, were such that this is how that stuff had to evolve and interact, would that be explanation enough? Or would Davies press on and ask, “But why does this stuff have these properties? Why do we live in a universe with this kind of stuff rather than some other kind of stuff? Why weren’t the initial conditions different, sending our world on a different trajectory?”
Is this what he’s after?
Would descriptions of how the universe might have been under such different circumstances be scientific explanation enough for Davies? Because I’m not at all certain that science can — or should — promise more than that.