Life is full of chances and changes, and the most prosperous of men may in the evening of his days meet with great misfortunes.

The right constitutions, three in number- kingship, aristocracy, and polity- and the deviations from these, likewise three in number - tyranny from kingship, oligarchy from aristocracy, democracy from polity.

In the first place, then, men should guard against the beginning of change, and in the second place they should not rely upon the political devices of which I have already spoken invented only to deceive the people, for they are proved by experience to be useless.

The line has magnitude in one way, the plane in two ways, and the solid in three ways, and beyond these there is no other magnitude because the three are all.

It [Justice] is complete virtue in the fullest sense, because it is the active exercise of complete virtue; and it is complete because its possessor can exercise it in relation to another person, and not only by himself.

A life of wealth and many belongings is only a means to happiness. Honor, power, and success cannot be happiness because they depend on the whims of others, and happiness should be self-contained, complete in itself.

Even when laws have been written down, they ought not always to remain unaltered.