Don't cross a river if it is four feet deep on average. — Nassim Nicholas Taleb

There is no effective difference between guessing a variable that is not random, but for which information is partial or deficient (...), and a random one (...). In this sense, guessing (what I don't know, but what someone else may know) and predicting (what has not taken place yet) are the same thing.

History is opaque. You see what comes out, not the script that produces events, [...] The generator of historical events is different from the events themselves, much as the minds of the gods cannot be read just by witnessing their deeds.

Categorizing is necessary for humans, but it becomes pathological when the category is seen as definitive, preventing people from considering the fuzziness of boundaries, let alone revising their categories.