" Of course, 1+1 makes 2 and blue to yellow gives green. But if we forget for a while the abstract knowledge or the laws of nature, and focus on the “knowledge” of particular situations, events, persons etc., then we can observe that it is almost never: “I know”; it is practically always: “I believe”.
Humans and all the intelligent creatures of this world operate through beliefs, more or less justified, more or less true, more or less convincing. Because the biological apparatus of one hundred percent accuracy has not yet been “invented” in nature. And it never will. "

― Giannis Delimitsos , A PHILOSOPHICAL KALEIDOSCOPE: Thoughts, Contemplations, Aphorisms