Dear Philosophers (and especially Prof. Pogge), I can see why an empirical theory of DESCRIPTIVE ethics is possible, but can there be an empirical theory of NORMATIVE ethics? It seems to me that, in the final analysis, you cannot deduce "ought" from "is". If all people are born (have evolved) to be selfish and cruel, does it follow that we should be selfish and cruel? Shouldn't we be considerate and kind, even if we are not born with these attributes?

Just to clarify terminology. I would understand an empirical theory of ethics as one that explains the activities of a group of ethicists. An empirical theory of descriptive ethics would seek to explain the activities of those who describe ethical beliefs and practices; and an empirical theory of normative ethics would seek to explain the activities of those who justify or challenge ethical beliefs and practices. An empirical theory of normative ethics would not itself seek to justify or challenge normative-ethical propositions.

Leaving terminology aside, I think what you mean to ask is whether an empirical account of how human beings behave has normative implications. In response, I would certainly agree that it does not follow from the fact that human beings tend to behave in certain ways that they ought to do so. Still, I would not think that empirical knowledge about human beings is normatively irrelevant. Two examples. If a morality is too complicated for human beings to understand or to follow with reasonably accuracy, then we might conclude that it is not the morality that human beings ought to try to follow. Similarly, if a morality is so demanding that we do not manage to educate most human beings to follow it, then again we would seem to have reason to conclude that it is not the morality human beings ought to try to follow. I see morality as solving the practical task of helping us live together peacefully and in a way that lets us flourish individually and collectively. On this account, we should be sensitive to empirical information and practical experience.

Should you be interested in more on this question, you might want to look at my exchange on this with Jerry Cohen (who takes the opposite view to mine). My response to his book -- Rescuing Justice and Equality -- is "Cohen to the Rescue!" in Ratio 21/4 (2008), pp. 454-75.

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