All Knowledge Is Conjectural

You have the feeling of certainty, you are absolutely sure that you're not wrong—this feeling is something we should always be skeptical of because when people have been absolutely certain, even in a domain as apparently full of certainty as mathematics, they've been shown to be wrong.

It is questioning these deepest assumptions that we have where we think there's no possible way we could be mistaken that leads to true progress, to genuine fundamental change, in the sciences and everywhere else.

All knowledge is conjectural. It's always being guessed. It's our best understanding at any given time.