@Cyracuz,
My knowledge, to the extent I had knowledge by a mix of reading, observation, and flat out being slapped by life, has varied over lots of decades. Only at the beginning, as I was taught to be a religious person, did I hold assurance, and even then, that assurance was more a kind of faith.
I later worked in a science lab for a bunch of years, and knowing wasn't the ongoing motivation. Quite the opposite, it was "what if?", combined with "let's see".
So, the question premise again doesn't fit to my experience - you seem to insist I know things for sure.