I forget most of what I read, just as I do most of what I have eaten, but I know that both contribute no less to the conservation of my mind and my body on that account.

The most dangerous untruths are truths slightly distorted.

What is the good of drawing conclusions from experience? I don't deny we sometimes draw the right conclusions, but don't we just as often draw the wrong ones?

The most heated defenders of a science, who cannot endure the slightest sneer at it, are commonly those who have not made very much progress in it and are secretly aware of this defect.

Do we write books so that they shall merely be read? Don't we also write them for employment in the household? For one that is read from start to finish, thousands are leafed through, other thousands lie motionless, others are jammed against mouseholes, thrown at rats, others are stood on, sat on, drummed on, have gingerbread baked on them or are used to light pipes.

A donkey appears to me like a horse translated into Dutch.

To err is human also in so far as animals seldom or never err, or at least only the cleverest of them do so.