How Do You Falsify Rationality?

I said I wasn’t going to write anything about the Paul Davies thing, but it’s been the hot topic for the last day or two, and I’ve found myself reading a bunch of the responses in blogdom. I basically agree with most of what various science bloggers have said, but being a contrary sort, I can’t help poking at a couple of points in the responses that seem a little iffy to me.

The main argument has centered around Davies’s claim that science has its own form of “faith:”

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.

Most of the responses have been essentially the same– I’ll quote Mike Dunford’s because it was the first I ran across in scrolling back through the ScienceBlogs feed:

The problem with this neat little argument is that science does not proceed on the assumption that nature is ordered. Science simply does not make that assumption. What science does is to ask the question, “is nature organized in a rational way.” Science asks that question – tests that hypothesis – every time someone conducts an experiment. So far, the answer has always been yes. But we don’t know that the answer will be “yes” the next time it’s asked any more than we know that the sun will come up tomorrow morning.

That’s pretty much the inevitable answer to Davies’s comment. The thing is, I’m not sure it’s strictly true, as written there.

Let’s put it a different way, though. When the subject turns to “Intelligent Design,” everybody always gets all Popperian, and starts going on about the need for falsifiability. So it seems only fair to apply the same criterion here, and ask the question:

What would it take to falsify the claim that “that nature is ordered in a rational and intelligible way?”

I think that’s a trickier question than most of the anti-Davies responses admit.

It’s easy to come up with examples of tests to falsify a particular model of how the world works– the Rayleigh-Jeans model of blackbody radiation, say, or the aether theory of the propagation of light, or local hidden variable theories in quantum mechanics. In all those cases, though, science simply moved on to another rational and systematic model of how the world works. Michelson-Morley overthrew the prevailing model of how nature was “ordered in a rational and intelligible way,” but it didn’t shake anybody’s conviction that there was some other rational and intelligible order to the universe. Quantum non-locality is tremendously disturbing on a philosophical level, but as much as it bothered Einstein, it’s still rational and intelligible.

So, how would you show that the universe is not rational and intelligible? It’s a tough question. I’m not sure there’s any one test that would do it– pretty much any single experiment could be accomodated by changing to a different rational model. It would require a large accumulation of evidence, but I’m not sure what evidence would be needed, as it’s hard to even think about what a non-rationally ordered universe would look like.

The idea “that nature is ordered in a rational and intelligible way” is such a bedrock assumption of the scientific process that I’m not sure it can meaningfully be said to be under examination in any experiment that I’m aware of.

Now, does this mean that Davies is right, and science depends on faith? Not really, or, rather, only if you define “faith” so broadly as to be essentially meaningless. It’s not even specific to science– after all, religion is founded on the idea “that nature is ordered in a rational and intelligible way,” as well, with the rational and intelligible basis being the will of God. It’s not just a bedrock assumption of science, it’s a bedrock assumption of humanity in general.

Hell, my dog clearly expects the world to be ordered in a rational and intelligible way– there are certain words, phrases, and actions that always lead to the same results (if I say “Are you hungry?” she licks her chops, and runs to her food bowl; if I put my shoes on and say “Do you want to go for a walk?” she runs to the back door), and she gets very distressed if you mess with that order (say, by taking too long to get to the door to go for that walk). She used to have a belief that food will sometimes magically appear in her bowl, but she’s figured out that Kate and I have something to do with that, and checks it more carefully after we’ve been preparing the sort of food that turns up in her bowl.

You’ve got to go pretty far down the food chain before you reach a point where there’s no expectation of rationality.

So, while I agree that Davies’s claim about science depending on faith is specious, it’s not because science is testing the idea of rational order to the universe. It’s a problem of definitions, and the definition of “Faith” needed for his argument to work is neither conventional nor useful.