This is our monthly thread for collecting these little gems and pearls of wisdom, rationality-related quotes you've seen recently, or had stored in your quotesfile for ages, and which might be handy to link to in one of our discussions.
- Please post all quotes separately, so that they can be voted up/down separately. (If they are strongly related, reply to your own comments. If strongly ordered, then go ahead and post them together.)
- Do not quote yourself.
- Do not quote comments/posts on LW/OB.
- No more than 5 quotes per person per monthly thread, please.
Euler is one of the few mathematicians who provide an exception to this rule. To quote Polya (Mathematics and Plausible Reasoning):
(the quoted passed in the text is apparently from Condorcet, although I don't know the initial source)
Polya is, of course, one of the few other mathematicians who break this mould. Explicitly writing books about the process of discovery.