>
You can do a lot with thought experiments that show logical inconsistencies in ideas without any actual knowledge of the factsYes, what you're getting at there is "a priori" knowledge in epistemological-speak and I agree that it forms the basis for much of what we consider true.
But, even the ability to accurately conduct and assess the results of those experiments relies on some set of facts. Your physics example speaks to exactly that: i.e. there's a foundation of "rules" that underpins the field, much of which have been developed through rigorous observation, experimentation, mathematical proof, etc. These rules form the "accepted truths" through which we are able to think critically about new ideas.
So, while we can debate degree, it should be clear that there has to be some accepted base reality to make sense of anything. And, of course, in this thread analogies to science are a bit of a digression. That is, the topic is fact-checking sites, which are largely about dispelling disinformation/misinformation of the social/political variety. So, for instance, whether x politician did or did not do something can be important to know when trying to critically assess their fitness.