Doubting everything and believing everything are two equally convenient solutions that guard us from having to think

...the feeling of mathematical beauty, of the harmony of numbers and of forms, of geometric elegance. It is a genuinely aesthetic feeling, which all mathematicians know

In one word, to draw the rule from experience, one must generalize; this is a necessity that imposes itself on the most circumspect observer.

The scientist does not study nature because it is useful; he studies it because he delights in it, and he delights in it because it is beautiful.

It is not order only, but unexpected order, that has value.

All that we can hope from these inspirations, which are the fruits of unconscious work, is to obtain points of departure for such calculations. As for the calculations themselves, they must be made in the second period of conscious work which follows the inspiration, and in which the results of the inspiration are verified and the consequences deduced.‎

Doubt everything or believe everything: these are two equally convenient strategies. With either we dispense with the need for reflection.