V. By these topics then which have been explained, a means of discovering and proving every sort of argument is supplied, as if they were elements of argument.  Have we then said enough up to this point?  I think we have, as far at least as you, an acute man and one deeply skilled in law, are concerned.  But since I have to deal with a man who is very greedy when the feast in question is one of learning, I will prosecute the subject so that I will rather put forth something more than is necessary, than allow you to depart unsatisfied.  As, then, each separate one of those topics which I have mentioned has its own proper members, I will follow them out as accurately as I can; and first of all I will speak of the definition itself.

Definition is a speech which explains that which is defined.  But of definitions there are two principal kinds:  one, of those things which exist; the other, of those which are understood.  The things which I call existing are those which can be seen or touched; as a farm, a house, a wall, a gutter, a slave, an ox, furniture, provisions, and so on; of which kind of things some require at times to be defined by us.  Those things, again, I say have no existence, which are incapable of being touched or proved, but which can be perceived by the mind and understood; as if you were to define usucaption, guardianship, nationality, or relationship; all, things which have no body, but which nevertheless have a certain conformation plainly marked out and impressed upon the mind, which I call the notion of them.  They often require to be explained by definition while we are arguing about them.

And again, there are definitions by partition, and others by division:  by partition, when the matter which is to be defined is separated, as it were, into different members; as if any one were to say that civil law was that which consists of laws, resolutions of the senate, precedents, the authority of lawyers, the edicts of magistrates, custom, and equity.  But a definition by division embraces every form which comes under the entire genus which is defined; in this way:  “Alienation is the surrender of anything which is a man’s private property, or a legal cession of it to men who are able by law to avail themselves of such cession.”

VI.  There are also other kinds of definitions, but they have no connexion with the subject of this book; we have only got to say what is the manner of expressing a definition.  This, then, is what the ancients prescribe:  that when you have taken those things which are common to the thing which you wish to define with other things, you must pursue them till you make out of them altogether some peculiar property which cannot be transferred to anything else.  As this:  “An inheritance is money.”  Up to this point the definition is common, for there are many kinds of money.  Add what follows:  “which by somebody’s death comes to some one else.”  It is not yet a definition, for