I expect the conclusion is correct, but the argument isn't really valid. Our knowledge of cells tells us only and precisely about our knowledge of cells. We have some gaping holes in our fundamental knowledge of the universe (what is it, how did it happen, etc) and nobody can claim with any certainty to understand how any of the basic things happen. It is a mystery of such epic proportions it is hard to even articulate what an answer could look like, let alone how we would work it out. That hasn't stopped the development of a bunch of useful models and theories of physics that explain a lot of local observations really well.