The whole point of my opening post is that the entirety of science is based on a major assumption for which there is no logical basis and which is inherently untestable.
Pum Fakert! If something is “untestable” then it is not “proven”. The reason why conclusions are “proven” (and even then it may be within the realm of statistical probability) is because the results can be replicated time and time again. If one time the results are not replicated, then the theory fails, or is modified to account for the new information. That is why your science book from 50 years ago is not the same as it is today. New theories have been “proven”, and old ones disproven.
The underlying “laws” are irrelevant to the conversation. Whether an apple falls due to gravity, general relativity or quantum gravity makes no difference to either yourself (when it hits you on the head) or the apple (although it may have other applications, which is why you may want to test the “why”).