The power which we possess, of making known all our complex or general ideas of things by means of definitions, is a faculty wisely contrived in the nature of language, for the increase and spread of science; and, in the hands of the skillful, it is of vast avail to these ends.

It is "the first and highest philosophy," instructing mankind, to think clearly and speak accurately; as well as to know definitely, in the unity and permanence of a general nature, those things which never could be known or spoken of as the individuals of an infinite and fleeting multitude.
8.

And, without contradiction, the shortest and most successful way of teaching the young mind to distinguish things according to their proper differences, and to name or describe them aright, is, to tell in direct terms what they severally are.

Cicero intimates that all instruction appealing to reason ought to proceed in this manner: "Omnis enim quse a ratione suscipitur de re aliqua institutio, debet a _definitione_ proficisci, ut intelligatur quid sit id, de quo disputetur."-- _Off_.

Lib.
i, p.4.Literally thus: "For all instruction which from reason is undertaken concerning any thing, ought to proceed from a _definition_, that it may be understood what the thing is, about which the speaker is arguing." Little advantage, however, will be derived from any definition, which is not, as Quintilian would have it, "Lucida et succincta rei descriptio,"-- "a clear and brief description of the thing." 9.