Everyone is perfectly willing to learn from unpleasant experience - if only the damage of the first lesson could be repaired.

He marvelled at the fact that the cats had two holes cut in their fur at precisely the spot where their eyes were.

I cannot say whether things will get better if we change; what I can say is they must change if they are to get better.

To read means to borrow; to create out of one s readings is paying off one's debts.

People who never have any time on their hands are those who do the least.

A good method of discovery is to imagine certain members of a system removed and then see how what is left would behave: for example, where would we be if iron were absent from the world: this is an old example.

The natural scientists of the previous age knew less than we do and believed they were very close to the goal: we have taken very great steps in its direction and now discover we are still very far away from it. With the most rational philosophers an increase in their knowledge is always attended by an increased conviction of their ignorance.