Tuesday, November 6, 2007

Evolution and moral knowledge

Consider this argument for moral scepticism (this formulation is based on a comment by Christian Lee). The existence of our moral beliefs can be given an evolutionary explanation which makes no reference to the truth of these beliefs, so that:
(*) If there were no moral truths, we'd still believe in moral truths.
This, the argument continues, is an undercutting defeater for our moral beliefs even if in fact there are moral truths.

I'm going to argue that at least on four metaethical views, (*) is false. But first note a complication. On many theories of morality, moral truths are necessary truths. But then (*) is a counterfactual with necessarily false antecedent and hence on Lewis semantics trivially true. However, this can't be how the evolutionary moral sceptic understands (*), since then (*) is going to be equally trivially true if one replaces moral claims with mathematical ones, and I take it that the moral sceptic isn't trying to argue for scepticism simpliciter. Rather, in the case of those theories of morality which make morality a necessary truth, the sceptic understands (*) to be a true per impossibile counterfactual. Now on to considering four moral theories.

1. Kantianism. On Kantian ethics, morality is very closely tied to practical rationality. If, per impossibile, there were no moral truths, there would be no practical rationality. If there were no such thing as practical rationality, there would be no agents or even potential agents. It is not clear whether on a Kantian view there could be any beliefs if there were no agents. If not, (*) is a false per impossibile counterfactual. Suppose that non-agents could have beliefs. Well, still, they wouldn't be our beliefs, because we really are agents, and being the sort of entity that has at least a potential for agency is essential to who we are.

2. Natural law. On natural law ethics, morality is grounded in the teleological features of our nature. If those features were other than they are, or if they were absent altogether, the nature would be significantly different, and the beings with that nature would be essentially different from us--they wouldn't be human. Thus, on natural law ethics, were there no moral truths, or even were the moral truths different from what they are, we wouldn't exist, and hence (*) is false.

3. Divine command metaethics of the divine-will variety. On this view, the right thing is what God wills us to (arbitrarily on some versions, or out of the goodness of his nature; the will in question is the antecedent will). Now, presumably God's deliberation as to what kinds of a universe to create was tightly intertwined with what actions, if any, he willed his creatures to do. It is very likely true that if there were no moral truths, i.e., if God had not willed any actions, then God would have created a significantly different universe (perhaps one in which finite agents would not have arisen), and similarly it is likely that if he had willed different moral truths, he would have set up evolutionary processes or intervened (or whatever is the right story about God's cooperation with evolution) to produce different creatures from the ones he had. In particular, it is unlikely that we would exist then, and hence (*) is probably false.

4. Divine nature metaethics. On this family of theories, the right is grounded in God's nature. For instance, the right may be imitation of God, or it may be a certain kind of participation in the Good which might be identified with God. But now consider the counterfactual. Were there no moral truths or were moral truths different, then God's nature would be different from what it is (e.g., it wouldn't be good). But God created us out of the goodness of his nature. Thus, likely, we wouldn't exist were God's nature different in moral respects from what it is. Hence, (*) is probably false, once again.

Note that on theories 2-4, I've also argued that the following variant of (*) is probably false:
(**) If moral truths were significantly different from what they are, our moral beliefs would be no different.


Anonymous said...


What would you call the loci classici of a "divine nature" metaethic?

Alexander R Pruss said...


I have no idea. I think Robert M. Adams defends something like this. It may be implicit in the work of anybody who thinks that the imitation of God is the foundation of ethics. Presumably Leibniz is committed to something like this: God commands the best commands in the best possible world for the best possible reasons because of his having the best possible nature.

David said...

Shouldn't one take the moral sceptic to be claiming, "If there weren't moral truths and if metaethical theories that imply that there are moral truths were all false, then we would still believe in moral values"?

David said...

The last word in my post should be "truths", not "values". Sorry.

Eli said...

I am almost positive that this is not legitimate. I think you're taking the word "we" too literally. In each section, you assume that "we" are people to whom a certain kind of morality actually applies. This, however, is contrary to the antecedent of the hypothesis and therefore you haven't disproved it in any sense.

To put a different spin on it, in each section you claim that we would not be who we are if that certain morality were significantly different. But these moral systems - along with the many others you didn't mention - are incompatible. Not all of them can be true, therefore, which according to this article means we don't actually exist as we do (regardless of what that even means).

You may be right that (*) is false, although I don't think you are, but these arguments don't show it.

Alexander R Pruss said...

The structure of my argument is this. Assume that there are moral truths. Then argue that (*) is false. Remember that I'm replying to the claim that (*) is true even if there are moral truths, so I am entitled to assume that there are moral truths.

I am also assuming that if there are moral truths, then probably some theory like one of these four is true. I then argue that each of these theories entails the negation of (*).

Eli said...

Yes, but taken together they also imply a contradiction. Somewhere your logic has broken down, therefore, and you need to fix it.

Further, you're still taking "we" too literally. Even if you insist on fixing humans the way we actually are, that's just making (*) into a straw man claim. I can reformulate it thusly: even if there were no morality, so long as there was something like a human with respect to how we believe, that entity would still be likely to believe in morality. The ways in which your hypothetical worlds operate don't say anything about the process of belief of their inhabitants, and that's what's under discussion here.

Alexander R Pruss said...

That's fine, but it's not clear that the modified version of (*) is a defeater to anything.

Eli said...

Okay, but then the argument it was designed to counter - namely, that if no morals exist, we could not have thought of them - is equally invalid for the same reason. It, too, would have to be evaluated using your criterion of assuming that the world actually works in the opposite way its proponents intend, at which point we can just turn your arguments around: assuming that no morals exist, we would not be us if they did in those various ways. To the extent that your arguments are accurate, they would be equally harmful to the other side. When I respond with this article to the next person who tells me that ethics could not exist if not for (say) God, I hope you won't mind. It will be nice to have a well-respected Christian author on my side.

Eli said...

Or, to be more specific, the claim this was designed to counter is that, if there were actually no morals, we would exist but also not believe in morals as we believe now. Like I say, it seems that you've defeated that claim as well as the other. Maybe you've opened up a new argument, along the lines of:

If some morality didn't actually exist, there would be no such thing as humans.
There is such thing as humans.
Therefore, some morality exists.

Although I think you'd have a harder time with that first premise than you might like.