A man is the origin of his action.

In poverty and other misfortunes of life, true friends are a sure refuge. The young they keep out of mischief; to the old they are a comfort and aid in their weakness, and those in the prime of life they incite to noble deeds.

The good lawgiver should inquire how states and races of men and communities may participate in a good life, and in the happiness which is attainable by them.

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.

For what one has to learn to do, we learn by doing.

It is our actions and the soul's active exercise of its functions that we posit (as being Happiness).

He who hath many friends hath none.