some of these are UNSOURCED (like it really matters all that much who said it), especially Einstein’s; people love attributing stuff to him so as to not be easily contradicted (“if einstein said it, then it must be true.”)

anyway, onwards:

The direct use of force is such a poor solution to any problem, it is generally employed only by small children and large nations.
David Friedman, politically topical

It is a capital mistake to theorize before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts.
Sir Arthur Conan Doyle, a man who believed in fairies as we all do

Some problems are so complex that you have to be highly intelligent and well informed just to be undecided about them.
Laurence J. Peter, riffing off The Curse Of The Intelligentsia

Intellectuals solve problems; geniuses prevent them.
Albert Einstein, failing to combine this with the idea behind the “and not simpler” maxim, so as to prevent anxious, fretful, and otherwise micromanaging people from justifying attacking even inconsequential problems

Nothing in the world can take the place of persistence. Talent will not; nothing is more common than unsuccessful people with talent. Genius will not; unrewarded genius is almost a proverb. Education will not; the world is full of educated derelicts. Persistence and determination alone are omnipotent. The slogan “press on” has solved and always will solve the problems of the human race.
Calvin Coolidge, who clearly had no fear of being executed (or at least heavily demoted) by said human race, which human race has a habit of taking people who’d gone too far on their quests–questionable, quixotic, brilliant, or belligerent–and (re)setting them “straight” aka making them no longer an outlier to mean public opinion (sometimes via straightforward elimination)

If you can talk brilliantly about a problem, it can create the consolling illusion that it has been mastered.
Stanley Kubrick, exposing one of my dirty little secrets

History is a vast early warning system.
Norman Cousins, expounding on the value of learning from theory and not necessarily on one’s own skin; do you really need to go through a heroin addiction to know that maybe you shouldn’t do that to yourself?

No problem can withstand the assault of sustained thinking.
Voltaire, clearly oversimplifying for the sake of aphorism, and not including the “stop thinking about it for a moment” heuristic, which often helps solve the very problem your conscious attention has trouble overcoming

Protracted siege.
Chris Langan, the Long Island doorman with an off-the-scale IQ and a proponent of untimed testing, on his preferred method of attack
It’s not that I’m so smart, it’s just that I stay with problems longer.
Albert Einstein, who, like Voltaire (above), seems to value persistence (though one would hope persistence NOT of the STAY THE COURSE variety, and instead a more nuanced version)