the answer to the persistent question, What is the purpose of the universe? is quite simply: There is none. - Alexander Rosenberg

Physics is by no means "finished". But the part of it that explains almost everything in the universe—including us—is finished, and much of it has been finished for a century or more. This includes the physics that we are going to need. Nothing at the unsettled frontiers of physics challenges the parts we're going to make use of. What's more, the physics we need is easy to understand, certainly far easier than quantum mechanics, general relativity, or string theory.

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.

The parts of science that rule out theism are firmly fixed. Finally, it's not just probable that God doesn't exist. For scientism, it's as close to a sure thing as science can get.