Tools may be animate as well as inanimate; for instance, a ship's captain uses a lifeless rudder, but a living man for watch; for a servant is, from the point of view of his craft, categorized as one of its tools. So any piece of property can be regarded as a tool enabling a man to live, and his property is an assemblage of such tools; a slave is a sort of living piece of property; and like any other servant is a tool in charge of other tools.

The roots of education are bitter, but the fruit is sweet.

Being a father is the most rewarding thing a man whose career has plateaued can do.

A courageous person is one who faces fearful things as he ought and as reason directs for the sake of what is noble.

All food must be capable of being digested, and that what produces digestion is warmth; that is why everything that has soul in it possesses warmth.

It is evident that the state is a creation of nature, and that man is by nature a political animal.

The senses are gateways to the intelligence. There is nothing in the intelligence which did not first pass through the senses.