In the final chapter of Braintrust, “Religion and Morality,” Patricia Churchland is doing an exegesis of The Euthyphro.
The pattern of questioning strongly hints, however, that whatever it is that makes something good or just or right is rooted in the nature of humans and the society we make, not in the nature of the gods we invent. There is something about the facts concerning human needs and human nature that entails that some social practices are better than others, that some human behavior cannot be tolerated, and that some forms of punishment are needed. [p 196]
That second sentence makes a nice summing up of the book, and it’s also what Sam Harris was trying to say but didn’t.