Why do I believe that the Sun will rise tomorrow?
Because I've seen the Sun rise on thousands of previous days.
Ah... but why do I believe the future will be like the past?
Even if I go past the mere surface observation of the Sun rising, to the apparently universal and exceptionless laws of gravitation and nuclear physics, then I am still left with the question: "Why do I believe this will also be true tomorrow?"
Where Recursive Justification Hits Bottom, Eliezer Yudkowsky
The Problem of Induction, first published by David Hume in 1739, is potentially a longstanding crack in the foundations of science. From LessWrong's tag:Induction page:
Modern views of induction state that any form of reasoning where the conclusion isn't necessarily entailed in the premises is a form of inductive reasoning [...] "The sun has always risen, so it will also rise tomorrow". [...] Contrary to deduction, induction can be wrong since the conclusions depend on the way the world actually is, not merely on the logical structure of the argument.
There has historically been a problem with the justification of the validity of induction. Hume argued that the justification for induction could either be a deduction or an induction. Since deductive reasoning only results in necessary conclusions and inductions can fail, the justification for inductive reasoning could not be deductive. But any inductive justification would be circular.
Dissolving the Problem of Induction, Liron
One of these maybe?
Not what I meant. You're talking about the problem of induction. I'm talking about arguing yourself into believing falsehoods.
1"At the foundation of well-founded belief lies belief that is not founded." (Wittgenstein, On Certainty) And more precisely: "The questions we raise and our doubts depend on the fact that some propositions are exempt from doubt, are as it were like hinges on which those turn." Hayek touches this obliquely - the error of demanding explicit justification for everything, including the knowledge that makes justification possible. To demand a proof-chain all the way down is to misunderstand how knowledge actually works. Albert's Münchhausen Trilemma is the critical-rationalist statement of the same problem: any demand for complete justification ends in infinite regress, circularity, or arbitrary stopping points. Some things are not the object of proof - they are the condition of proof.
I remember reading a quote, I think from the Buddhist or some other Eastern tradition, about how if you've argued yourself into believing the Sun doesn't exist, you've gone horribly wrong. It went something like "Nothing can be known, if even the Sun requires proof". I think I read it either on LessWrong or on gwern.net several years ago, but for the life of me I can't find it. I remember it being phrased more poetically than prosaically.
Does anyone know what quote I'm referring to, and where to find it?