Well, it's true. Genetic changes are caused by cosmic rays, or toxins, or whatever else. Natural selection decides whether those changes stay or go. (usually go, at least 99.9% of the time)
Darwinian natural selection, which I was under the impression we were discussing, proposes a paradigm that consists of two important behaviors--variation, and selection. If you keep over-applying occam's razor to every standard definition of the theories we are discussing, you are going to cut yourself into epistemological shreds.