To appear in Heams et al. (eds.), Handbook of Evolutionary Biology (provis. Title), Springer.

Please do not quote without permission. This is not the final version

psychological and neuronal systems linked to moral thought and action. Occasionally, the evolutionary approach can prove a useful tool in addressing these questions (Gibbard 1990, Haidt 2001, Nichols 2004). We will see an example of this in the last section of this article.

## 6. The delicate shift from the factual to the normative

The question that is really interesting for moral philosophy is whether an evolutionary understanding of the emergence of morality has an influence at the level of normative ethics. David Hume (1991), George Moore (1998), and many others in their wake have justly noted how difficult it is to draw normative conclusions on the basis of descriptive considerations. ethicists28. Yet this is exactly the project of many evolutionary

There are many attempts to define the moral good by means of a concept that can be completely explained in an empirical manner. For example, according to Larry Arnhart, the moral good is equivalent to what is desirable from the point of view of human nature, which means that which has been generally desired by human beings throughout their evolutionary history: a complete life, parental care, sexual relations, family ties, friendship, social hierarchy, justice as reciprocity, etc. (Arnhart 1998). Along the same lines, Robert Richards defends the idea that the moral good corresponds to altruism, understood in the sense of promoting the good of the community (Richards 1986). G. E. Moore (1998) is known for having taken up arms against this kind of definition of the moral good. In one sense, he is right. It seems that one loses something important if one tries to reduce morality to descriptive facts. The claim that a concept or a moral statement can be reformulated in purely descriptive terms is in direct contradiction with a very widely shared conviction that the moral does not belong to the same category as the descriptive. If such a reduction could be made, there would be no way of accounting for the differences and the relations holding between the moral and the descriptive (for example, the fact that moral notions, in contrast to descriptive notions, are prescriptive in nature). Furthermore, if one wants to carry the reductionist project through to the end and propose a description of the moral good that is both clear and free from any normative component, one risks at the same time losing any interest we have in speaking of morality. In a way, we throw the baby out with the bathwater. If the normative reduces completely to the descriptive, we can ask why it is still useful to engage in moral reflection! By desiring its demystification too strongly, we end up losing it. However, it is worth noting that this criticism is not valid against attempts at producing a 'non-exhaustive' definition of the moral good. It might be useful to come up with a definition that furnishes us with some understanding of the moral good without any pretentions to conceptual identity (see Putnam 2002 on this). For instance, one could say that the moral good has a relation to cooperation and awareness of others' interests. This is a useful descriptive explanation whose relevance one cannot dismiss a priori.

Faced with the inability to provide an exhaustive definition of the moral good in descriptive terms, some might be tempted to construct a logical argument with the aim of deriving a normative conclusion from descriptive premises. Here is an example of this kind of argument:

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