We know this: at one point there was no life. Now there is. Somewhere between these two points life came to be. We do not know how. We
could throw up our hands and go "must be magic!". But why would we? Every single time anyone has ever accredited anything to a supernatural process before they have been wrong. Why should we take the assumption that it is now?
We have no evidence either way, however one form of explanation has a track record of success, and the other a track record of failure. Which form then is most rational to assume?