It is the rule of rules, and the general law of all laws, that every person should observe those of the place where he is.

In general I ask for books that make use of learning, not those that build it up.

He that I am reading seems always to have the most force.

If I can, I shall keep my death from saying anything that my life has not already said.

Since I would rather make of him an able man than a learned man, I would also urge that care be taken to choose a guide with a well-made rather than a well-filled head.

Obsession is the wellspring of genius and madness.

Whenever a new finding is reported to the world people say - It is probably not true. Later on, when the reliability of a new finding has been fully confirmed, people say - OK, it may be true but it has no real significance. At last, when even the significance of the finding is obvious to everybody, people say - Well, it might have some significance, but the idea is not new.