How Much Is It Due to Descartes' Influence?

Scientific method was not yet developed by this time. How do i know about speed of light or the laws of thermo dynamics? It's not because now i see them illustrated with my eyes. We might not even really, unless we know enough about science, know how some of these laws, like whitch laws, instantiate which things. But certainly that goes for other other well, not got the law of inertia, actually.