Hume’s Law says that we cannot logically derive prescriptions (oughts) from descriptions (is’s). Hume’s Law is true. Evolutionary intuitionism does not violate Hume’s Law.
Here’s the kind of argument used here: “You are of value. If someone is of value, they should be preserved from damage or destruction. Therefore, I ought to rescue you when you are in danger.”
The connection between value and its preservation is conceptual, so it is no problem. What we have to explain is the premise “You are of value.”
There is an evolutionary account of the origin and development of belief. Unlike most beliefs, it is not acquired in the light of evidence. It is naturally selected rather than acquired. It is not true. There is no sense in which we ought to believe it. It is not derived from other beliefs. We end up believing it for evolutionary reasons that are independent of logic. Once we believe it, however, we have commitments.
Here is an analogy. No individual has an obligation to adopt a particular child. Once they do, however, they automatically acquire obligations with respect to the child. The explanation of the origin of the obligations goes back to the adoption. The explanation of the adoption is not, however, part of the explanation of the origin of the obligations.
An evolutionary explanation for a belief is not the logical derivation of the belief from other propositions, which is what Hume’s law declares to be impossible. Indeed, the way outlined here, which involves a naturally selected belief with normative content, is probably the only way in which to explain how there can be prescriptions in the natural world without violating Hume’s Law.