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?

We accumulate our opinions at an age when our understanding is at its weakest.

I ceased in the year 1764 to believe that one can convince one’s opponents with arguments printed in books. It is not to do that, therefore, that I have taken up my pen, but merely so as to annoy them, and to bestow strength and courage on those on our own side, and to make it known to the others that they have not convinced us.

First there is a time when we believe everything, then for a little while we believe with discrimination, then we believe nothing whatever, and then we believe everything again - and, moreover, give reasons why we believe.

As nations improve, so do their gods.

If an angel were to tell us about his philosophy, I believe many of his statements might well sound like '2 x 2= 13'.

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.