The best friend is he that, when he wishes a person's good, wishes it for that person's own sake.

It is a part of probability that many improbable things will happen.

Educating the mind without educating the heart is no education at all.

It is clear, then, that the earth must be at the centre and immovable, not only for the reasons already given, but also because heavy bodies forcibly thrown quite straight upward return to the point from which they started, even if they are thrown to an infinite distance. From these considerations then it is clear that the earth does not move and does not lie elsewhere than at the centre.

He who thus considers things in their first growth and origin ... will obtain the clearest view of them.

A period may be defined as a portion of speech that has in itself a beginning and an end, being at the same time not too big to be taken in at a glance

In the works of Nature, purpose, not accident, is the main thing.