How does one blindly trust first principles? I’m confused by that

They don't test any of their presuppositions that have been given to them. First principles may have been a poor word choice, sorry One good example is virology. People who work in that field don't realize that viruses have never been proven to exist. They just accept the belief that they exist and build their life's work on that foundation of sand In order to say that x causes y, you must first prove the existence of x. X in the case of virology hasn't been proven. Just an example that will cause a lot of cog diss for most reading this. Pls go look it up for yourself if you don't believe me