Moral Letters to Lucilius

suit even our nice tastes. For what can we do, my dear Lucilius? How otherwise can we find a word for that which the Greeks call οὐσία, something that is indispensable, something that is the natural substratum of everything? I beg you accordingly to allow me to use this word essentia. I shall nevertheless take pains to exercise the privilege, which you have granted me, with as sparing a hand as possible; perhaps I shall be content with the mere right. Yet what good will your indulgence do me, if, lo and behold, I can in no wise express in Latin280 the meaning of the word which gave me the opportunity to rail at the poverty of our language? And you will condemn our narrow Roman limits even more, when you find out that there is a word of one syllable which I cannot translate. “What is this?” you ask. It is the word ὄν. You think me lacking in facility; you believe that the word is ready to hand, that it might be translated by quod est. I notice, however, a great difference; you are forcing me to render a noun by a verb. But if I must do so, I shall render it by quod est. There are six ways281 in which Plato expresses this idea, according to a friend of ours, a man of great learning, who mentioned the fact today. And I shall explain all of them to you, if I may first point out that there is something called “genus” and something called “species.”

For the present, however, we are seeking the primary idea of “genus,” on which the others, the different “species,” depend, which is the source of all classification, the term under which universal ideas are embraced. And the idea of genus will be reached if we begin to reckon back from particulars; for in this way we shall be conducted back to the primary notion. Now “man” is a species, as Aristotle282 says; so is “horse,” or “dog.” We must therefore discover some common bond for all these terms, one which embraces them and holds them subordinate to itself. And what is this? It is “animal.” And so there begins to be a genus “animal,” including all these terms, “man,” “horse,” and “dog.” But there are certain things which have life (anima) and yet are not “animals.” For it is agreed that plants and trees possess life, and that is why we speak of them as living and dying. Therefore the term “living things” will occupy a still higher place, because both animals and plants are included in this category. Certain objects, however, lack life⁠—such as rocks. There will therefore be another term to take precedence over “living things,” and that is “substance.” I shall classify “substance” by saying that all substances are either animate or inanimate. But there is still something superior to “substance”; for we speak of certain things as possessing substance, and certain things as lacking substance. What, then, will be the term from which these things are derived? It is that to which we lately gave an inappropriate name, “that which exists.” For by using this term they will be divided into species, so that we can say: that which exists either possesses, or lacks, substance.

This, therefore, is what “genus” is⁠—the primary, original, and (to play upon the word) “general.” Of course there are the other genera: but they are “special” genera: “man” being, for example, a genus. For “man” comprises species: by nations⁠—Greek, Roman, Parthian; by colours⁠—white, black, yellow. The term comprises individuals also: Cato, Cicero, Lucretius. So “man” falls into the category “genus,” in so far as it includes many kinds; but in so far as it is subordinate to another term, it falls into the category “species.” But the genus “that which exists” is general, and has no term superior to it. It is the first term in the classification of things, and all things are included under it.

The Stoics would set ahead of this still another genus, even more primary; concerning which I shall immediately speak, after proving that the genus which has been discussed above, has rightly been placed first, being, as it is, capable of including everything. I therefore distribute “that which exists” into these two species⁠—things with, and things without, substance. There is no third class. And how do I distribute “substance”? By saying that it is either animate or inanimate. And how do I distribute the “animate”? By saying: “Certain things have mind, while others have only life.” Or the idea may be expressed as follows: “Certain things have the power of movement, of progress, of change of position, while others are rooted in the ground; they are fed and they grow only through their roots.” Again, into what species do I divide “animals”? They are either perishable or imperishable. Certain of the Stoics regard the primary genus283 as the “something.” I shall add the reasons they give for their belief; they say: “in the order of nature some things exist, and other things do not exist. And even the things that do not exist are really part of the order of nature. What these are will readily occur to the mind, for example centaurs, giants, and all other figments of unsound reasoning, which have begun to have a definite shape, although they have no bodily consistency.”

But I now return to the subject which I promised to discuss for you, namely, how it is that Plato284 divides all existing things in six different ways. The first class of “that which exists” cannot be grasped by the sight or by the touch, or by any of the senses; but it can be grasped by the thought. Any generic conception, such as the generic idea “man,” does not come within the range of the