Classically (and etymologically) moral nihilism is the philosophy that nothing has value. Morality is dealt with by ethics, of course, but in the phrase, it is a mere adjective. It only modifies the word “value”, and value is a concept of aesthetics. So, moral nihilism in that sense is an aesthetical statement.
Quentin Smith, a modern eclectic atheist philosopher, believes that he has shown God does not exist by proving that moral nihilism is true. He has done this by redefining moral nihilism to mean “it does not morally matter what we do”. I don’t have a problem with a philosopher (or scientist, or whatever) borrowing terms from ordinary usage and redefining them for a new usage. It’s done all the time in every field of more than trivial technical complexity.
So, working with Smith’s definition, the first thing that pops out at us is that he has made a purely ethical statement of it. The second thing that pops out is that it seems to contradict what Smith himself has argued for some time: namely, that moral realism — in fact, global moral realism — is true, which means that he believes everything has value. And in fact, the noncontingent truth of global moral realism is the first premise of his proof.
Before getting too deeply into his rather complicated development of his proof (which includes the assumption that future time is infinite) I’m wondering whether there is any interest in discussing it. Would any atheists be interested in examining an argument that, if sound, directly implies that God does not exist? (Similar to the way in which Peano’s five axioms directly imply that 1 + 1 = 2.)
Theists are welcome to participate, of course. But be forewarned that if a flaw in the argument cannot be found, then the argument’s conclusion must be accepted. If Smith’s premises are true, and his inferences valid, then there can be no denial that God does not exist.
Here’s the relevant paper, for anyone interested: Moral Realism and Infinite Spacetime Imply Moral Nihilism
Anyone? Anyone? Beuller? Beuller?