I think you are wrong. If he is following the scientific method, and he doesn't have evidence, he should 'conclude' that. The key is that in science, you never

I think you are wrong. If he is following the scientific method, and he doesn't have evidence, he should 'conclude' that. The key is that in science, you never 'conclude' (in the sense of finalize) anything. Everything is temporal until new evidence deny your current understanding.