It is evidently equally foolish to accept probable reasoning from a mathematician and to demand from a rhetorician demonstrative proofs.
AristotleTools 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.
AristotleNor was civil society founded merely to preserve the lives of its members; but that they might live well: for otherwise a state might be composed of slaves, or the animal creation... nor is it an alliance mutually to defend each other from injuries, or for a commercial intercourse. But whosoever endeavors to establish wholesome laws in a state, attends to the virtues and vices of each individual who composes it; from whence it is evident, that the first care of him who would found a city, truly deserving that name, and not nominally so, must be to have his citizens virtuous.
Aristotle