Be attentive, feel nothing in vain, measure and compare: this is the whole law of philosophy.

Many are less fortunate than you' may not be a roof to live under, but it will serve to retire beneath in the event of a shower.

Man can acquire accomplishments or he can become an animal, whichever he wants. God makes the animals, man makes himself.

The more experiences and experiments accumulate in the exploration of nature, the more precarious the theories become. But it is not always good to discard them immediately on this account. For every hypothesis which once was sound was useful for thinking of previous phenomena in the proper interrelations and for keeping them in context. We ought to set down contradictory experiences separately, until enough have accumulated to make building a new structure worthwhile.

There is no more important rule of conduct in the world than this: attach yourself as much as you can to people who are abler than you and yet not so very different that you cannot understand them.

To see every day how people get the name 'genius' just as the wood-lice in the cellar the name 'millipede'-not because they have that many feet, but because most people don't want to count to 14-this has had the result that I don't believe anyone any more without checking.

Just as the performance of the vilest and most wicked deeds requires spirit and talent, so even the greatest demand a certain insensitivity which under other circumstances we would call stupidity.