Evaluating whether something is likely to be true is not the same thing as evaluating whether something is true.

If I'm in a windowless room and don't know whether it's raining outside, I might assume based on the season that it is more or less likely to be currently raining.

That does not mean that if I actually look outside in the middle of summer, I won't believe my eyes if I see raindrops.

> The fallacy lies in assuming anything connected w/ authority.

If we didn't take shortcuts in generalizations no generation would get further than the previous. Of course you can generally assume an authority on a subject is correct. That doesn't mean you can't or shouldn't question them, just that most of the time you'd simply be wrong.