You joke, but it’s still a valid way of doing it.

If we are going be inquisitive in a systematic manner, we have to measure things in comparison, and to start doing that we had to start somewhere, in every single different field. Eventually we got to the speed of light as a constant, figured out the 1/137 fine structure constant, the helical configuration of DNA and RNA, etc., all starting from arbitrary suppositions, getting honed and adjusted by laboratory and thought experiments.