You are again assuming the conclusion. While science may not be able to prove a supernatural cause this does not mean that there must therefore be a natural one. Indeed, at present all science can now say is that a natural cause for the origin of life has not been shown.
By analogy I cannot show nuclear reactions by the laws of chemistry. If my tools of research were limited to chemistry it would not allow me to say that there must be a chemical explanation that has yet to be discovered. Without a knowledge of atomic particles I could at best say that there might be an unknown chemical explanation.
Similarly, at best the natural sciences can at best say that there might be a natural explanation for the origin of life. Then again, there might not.
later pingout.
It's not "assuming the conclusion", it's a working assumption to facilitate investigation - if you don't assume there's a material cause for material events, then there's no point in looking, because science is not equipped to investigate the nonmaterial. If it turns out that no material cause can be found, so be it, but if you don't start with that assumption, you can't start looking at all. As a matter of science, of course - theological or philosophical investigations are another matter entirely.
Hello? If something is supernatural, it isn't constrained to natural laws. Are you not thinking??? It doesn't matter at all what the conclusion is.