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—th… - Alexander Rosenberg

What we know of physical and biological science makes existence of God less probable than the existence of Santa Claus. And the parts of physics that rule out God are not themselves open to much doubt. There is no chance that they will be revised by anything yet to be discovered. To be sure, there will be revolutionary developments in science. Superstring theory may give way to quantum-loop gravity; exceptions to the genetic code may be discovered; some unique function of consciousness may be identified. But there are some things that won't happen. Purposes and designs will never have a role in physics and biology. Perpetual motion machines and other violations of the laws of thermodynamics won't arise, not even if there turns out to be such a thing as cold fusion.

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.

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.