“No moral code is right, correct, true. That's nihilism. And we have to accept it.”
The Atheist's Guide to Reality (2011)
Context: Scientism starts with the idea that the physical facts fix all the facts, including the biological ones. These in turn have to fix the human facts—the facts about us, our psychology, and our morality. After all, we are biological creatures, the result of a biological process that Darwin discovered but that the physical facts ordained. As we have just seen, the biological facts can't guarantee that our core morality (or any other one, for that matter) is the right, true, or correct one. If the biological facts can't do it, then nothing can. No moral code is right, correct, true. That's nihilism. And we have to accept it.