I think you don't have to believe theory x to experience it first, though. You can also just try it out - "assume that x is true, what are the consequences". I

I think you don't have to believe theory x to experience it first, though. You can also just try it out - "assume that x is true, what are the consequences". I think a person's own experience should always form the bottom line of their world view, though. Otherwise you simply get completely lost. How do you know whom to believe? There will always be people claiming contradicting things. Ultimately you have to at least trust yourself. At least I have drawn that line for myself at some point. I still take into account that I could be wrong, but to sway me, more is required than a mere "believe me, I have more experience than you". Of course there are also things where it doesn't really matter. Not every decision questions my whole world view. If I work together with somebody more experiences and they say "let's stick to Postgres instead of using MongoDB" or whatever, I have no problems following their advice (I would then perhaps try MongoDB on another, less risky occasion).