Naturalist Ethics

Brian Weatherson of Crooked Timber takes issue with my co-blogger's post on the impossibility of naturalist ethics. He writes:

Say we know the following facts about the world. It contains creatures who are capable of feeling pleasure and pain, who have hopes and plans and fears and regrets, who are capable of great learning, and creating works of great beauty, who often love their children and parents and occasionally love each other, and who have emotional attachments to those people who they love so they are affected by the pleasures, pains, successes, failures etc of those they love. Now a naturalist could easily come to know all these things about the world.

The person who thinks naturalism can’t ground ethics thinks that we could know all those things about the world and still think it’s a wide open empirical question whether it is morally wrong to torture one of those creatures for one’s own amusement, or to kill all of these creatures to relieve a minor headache one has, and so on.

The obvious response is that Weatherson isn't relying on a purely naturalistic set of physical facts. He's smuggling in a moral premise, namely the principle that it is wrong to torture (for one's own amusement) creatures who are capable of feeling pleasure and pain, who have hopes and plans and fears and regrets, who are capable of great learning, and so forth. Only with that principle in place does it make sense to say that you can derive a moral conclusion from the set of facts Weatherson lays out.

But where does that principle come from in the first place? That's the question. And Weatherson presents no reason to think that a set of physical facts alone can supply it.

I really don’t think that anyone around here seriously thinks that in such a position we have to do extra work to find out whether it’s right or wrong to torture these creatures for fun. We already know enough to know full well that it isn’t.

Says who? Is that just a feeling that many people happen to share at this point in history? Is there any ontological grounding outside of our own feelings? And remember: "We" used to "know" that slavery was morally permissible. Was it? By what set of physical facts can one condemn practices that are widespread and quite possibly superior in Darwinistic terms?

In case this isn’t entirely obvious (and frankly I can hardly think of a more secure premise in ethics, but just in case) try the following thought experiment. Imagine we find out tomorrow that all theistic theories are just wrong. (Everyone makes mistakes.) There’s really nothing around here but us baryons. Would anyone, I mean anyone, think that suddenly we had no ethical obligations whatsoever? That it was now OK to torture babies for fun? To put the point in Bayesian terms, anyone whose confidence in any extra-natural hypothesis is as high as their confidence in the proposition that it’s wrong to torture babies for fun has a very odd worldview.

Here's a question: If there is no God, is it moral for spiders to eat flies for fun? Or (I'm riffing on Lawrence Solum's invocation of an example from Philippa Foot here), is it immoral for a bear to slaughter a deer for fun? Do these questions even make sense? No -- bears and spiders do what they do, and morality isn't even relevant. And if those questions don't make sense for bears and spiders, why would it make any more sense to ask the same sort of question about us language-using animals?

And it's not a question of degrees of confidence, except in this sense: We think that torturing babies for fun is really, really wrong. We think that this is not just a personal feeling, but a moral truth that is binding whether or not anyone agrees with it. But how is it possible to have moral truths that are binding on all individuals throughout time and space? If it is impossible to derive such moral truths from purely physical facts, something else is required. If the existence of God would make such moral truths possible, then perhaps our confidence in moral truth should be translated into a confidence in God's existence.

Imagine that you wake up to find yourself in a space suit on the moon. In that situation, you would be justified in arguing thus: 1) It is impossible for a mere human like me to fly to the moon without the aid of some sort of spaceship. 2) I find that I am on the moon. 3) Conclusion: I must have been flown here on some sort of spaceship.

Weatherson's response strikes me as analagous to this: "I am more confident of the fact that I'm on the moon than I am in the existence of spaceships. I can imagine a possible world in which spaceships don't exist, and yet I somehow find myself on the moon. Therefore I might have the capacity to have flown here of my own accord."