If you are to be kept right, you must possess either good friends or red-hot enemies. The one will warn you, the other will expose you.

Wise kings generally have wise counselors; and he must be a wise man himself who is capable of distinguishing one.

As houses well stored with provisions are likely to be full of mice, so the bodies of those that eat much are full of diseases.

Aristotle was once asked what those who tell lies gain by it. Said he - That when they speak truth they are not believed.

To become self-educated you should condemn yourself for all those things that you would criticize others.

Antisthenes used to say that envious people were devoured by their own disposition, just as iron is by rust. Envy of others comes from comparing what they have with what the envious person has, rather than the envious person realising they have more than what they could have and certainly more than some others and being grateful. It is really just an inability to get a correct perspective on their lives.

Protagoras asserted that there are two sides to every question, exactly opposite to each other.