If someone argues for common ground between science and religion, some people will resist, and some people—maybe the same ones—will misunderstand. And so it might help to point out what I’m not about to do. I’m not offering a defense of theism. In fact, if someone insists that the point I’m making isn’t really about religion, I’m not necessarily inclined to disagree. But I suspect many scientists hold beliefs that go beyond anything the evidence could ever show, and that they hold them because they think the world wouldn’t make sense without them. And even though it doesn’t exhaust religion, a religious outlook is partly a matter of thinking that the world makes sense in a way that isn’t just a matter of our projecting sense onto it.
My point takes us back to my favorite philosopher, David Hume. Hume is my favorite not because I agree with him (I often don’t) but because the question “What would Hume say?” is so often so useful. It’s a reminder that many of the things we think are a lot less obvious than we’d like.
In particular, I want to focus on what Hume had to say about cause and effect, and about laws of nature. I won’t worry about whether what I say captures what the real Hume thought. My Hume is the one most philosophers met as undergrads. It’s also the one behind David Lewis’s term “Humean supervenience.” This Hume believed that there’s no such thing as causal connection. There’s no “nexus” between cause and effect that connects them and underwrites the production of the effect from the cause. If this Hume is right, then we can talk of forces and powers as shorthand ways of describing regularities in the phenomena, but we have no good argument for thinking of them as something that glues things together and keep the world running. The world, on this view, is just one damn thing after another. As it happens, the damn things form patterns—or at least so they have so far in the parts of the whole that we have access to. But there’s nothing deep about this; there’s no underlying necessity. To use Lewis’s useful word, there’s just the mosaic—the totality of events, with whatever regularities it contains. To put it another way, Nature doesn’t have a nature.
I don’t have data, but I’d bet that most scientists don’t see the world that way. I’d bet a great many scientists think that forces, structure, causes, laws underly the patterns we see rather than being exhausted by them. One reason is that it’s hard to keep the Humean picture in your head. Hume—unlike many Humeans—was honest about this. I sometimes suspect that he was the only Humean in history devoid of bad faith. If the Humean picture is correct, then the way events in the world are arranged just is; there’s no deep difference between a world with laws and a massive cosmic coincidence. We count patterns as laws, and we describe things with causal talk when the patterns happen to turn out in certain ways. But in Hume’s wonderful phrase, all things really are loose and separate. Even the fact that the end of your sentences bear a rational relationship to their beginnings is, sub specie aeternitatis, just a lucky fluke.
I doubt that any of us can seriously see ourselves as Humeanism requires. Insofar as we take ourselves to be rational agents, we can’t also see ourselves as Humean congeries. But my guess is that when scientists think about the world beyond themselves, they also reject the Humean view. I’d expect this to be particularly true of physicists. I’d expect them to be particularly inclined to think that our best theories are getting at something deep. Nonetheless, there’s no empirical justification for looking at the world that way. Nothing that could ever turn up in ordinary observation nor in the lab is incompatible with Humeanism. There’s at least a logically possible world where Humeanism is true and all the appearances are exactly as they are in this one.
I sometimes joke that my religion is that I’m not a Humean. The point is that I don’t think I can show that the Humean picture is false, but I can’t shake the thought that the world makes more sense than Humeanism allows. If naturalism is the view that everything important about the world is scientifically accessible, then I’m not a naturalist.
This doesn’t add up to religion. Religious believers have more elaborated views of what gives the world its sense. But unless you’re a rare sort of person, I’m betting you’re not a Humean (maybe even if you say you are!). And so I’m betting that you think there’s more to the world than science can tell us. At least to that extent, you have something in common with religious believers even if you usually think otherwise.