Plato’s moral realism Notes for September 21

Main points

Where do the moral rules we’ve been talking about come from? One prominent answer is that they are rules given to us by a supernatural being. Plato raises a significant problem for that answer.

Plato takes his argument to support moral realism. That’s the view that the truth of moral beliefs is independent of what anyone thinks, much like the truth about other matters of objective fact.

After talking about Plato’s argument, we explored whether it might be extended to a non-realist account of moral beliefs: that they are the product of social customs.

The problem for theological ethics

Here’s the version of the Euthyphro problem that has bedeviled (so to speak) Christian ethics.

Does God choose the rules he does because they are right or for some other reason?

If God chooses the rules because they are right, then things are right or wrong independent of God’s decisions. That would mean that God does not create right and wrong.

If God chooses the rules for some other reason (or no reason at all), then he seems capricious or irrational.

And for non-theological ethics?

We can ask a similar question: why do we think that letting the child drown would be wrong? Is it because it is wrong or for some other reason? If it’s the former, then, it seems, we have to think of moral rules as being objective matters of fact. If it’s the latter, then our moral beliefs are capricious or irrational.

Or so it seems.

We talked about how someone might offer an explanation of why we believe that letting the child drown would be wrong that treats morality as a kind of human creation that does not obviously trip over Plato’s argument.

Willie proposed that societies develop moral rules, such as the prohibition on killing, to establish peace and order. I’m less interested in the specific story than I am in the kind of explanation it is. It proposes that we do not respond to objective moral facts but rather that we have the moral beliefs that we do for some other reason.

Suppose Willie’s explanation were true. Would our moral beliefs be capricious or irrational? It’s not easy to say. On the one hand, the correct explanation of our moral beliefs would diverge from what we believe. We think that murder is just wrong. And it would be wrong even if it wouldn’t bring society down (as, frankly, just about no individual moral wrongs ever do). On the other hand, these explanations make a lot of sense. Willie’s explanation gives at least one reason why it’s a good thing to have the moral rules that we do.

It seems to me that Plato’s argument poses a pressing problem for views that treat moral rules as the conscious creation of a being, whether natural or supernatural. It leads naturally to a question about the anthropological kind of explanation that Willie proposed. But Willie’s style of explanation might have an easier time answering it.

This page was written by Michael Green for Problems of Philosophy, Philosophy 1, Fall 2009. It was posted September 23, 2009.
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