There are two famous arguments against moral naturalism: the Humean 'is-ought' distinction and Moore's naturalistic fallacy. González-Cabrera offers counter-arguments to them from the viewpoint of evolutionary ethics.

First, Hume's Law prohibits inference from factual premises ("is") to prescriptive conclusion ("ought"), which implies that ethical claims cannot be justified within the naturalistic framework. González-Cabrera employs A. Gewirth's argument and claims that the derivation of "ought" from "is" is not controversial if there is a goal related to a proposed "ought" statement.

Second, Moore's naturalistic fallacy shows that the question "what is (moral) good?" cannot be answered by an appeal to non-moral properties. González-Cabrera points out that Moore's analytic project overlooks multiplicity of our common-sense notion of moral goodness. The question "what is (moral) good?" can be answered in a naturalistic way if it is interpreted not as "what is the common-sense notion of 'good'?" but as "how we should make a theoretical notion of goodness?"

These two points are connected by evolutionary ethics. It explicates morality as a product of natural selection. Here, cooperation plays a role as the goal of moral "ought" because of its contribution to survival and reproduction. Evolutionary ethics is an effective naturalist theory which satisfies the requirement for a theory about what is moral goodness.

Evolutionary ethics indeed lends a powerful support for moral naturalism. An important question would be how thoroughly it can account for our moral practice, especially in aspects which are unique to human cooperative behavior.

(Haruka TSUTSUI)