Sextus Empiricus (adv. Mathem. vii. p. 269-282) gives a different vein of reasoning respecting predication,--yet a view which illustrates this doctrine of Antisthenes. Sextus does not require that all predication shall be restricted to identical predication: but he maintains that you cannot define any general word. To define, he says, is to enunciate the essence of that which is defined. But when you define Man--"a mortal, rational animal, capable of reason and knowledge"--you give only certain attributes of Man, which go along with the essence--you do not give the essence itself. If you enumerate even all the accompaniments ([Greek: sumbebêko/ta]), you will still fail to tell me what the essence of Man is: which is what I desire to know, and what you profess to do by your definition. It is useless to enumerate accompaniments, until you explain to me what the essence is which they accompany. These are ingenious objections, which seem to me quite valid, if you assume the logical subject to be a real, absolute essence, apart from all or any of its predicates. And this is a frequent illusion, favoured even by many logicians. We enunciate the subject first, then the predicate; and because the subject can be conceived after abstraction of this, that, _or_ the other predicates--we are apt to imagine that it may be conceived without _all or any_ of the predicates. But this is an illusion. If you suppress all predicates, the subject or supposed substratum vanishes along with them: just as the Genus vanishes, if you suppress all the different species of it. "Scais-tu au moins ce que c'est que la matière? Très-bien. . . Par exemple, cette pierre est grise, est d'une telle forme, a ses trois dimensions; elle est pésante et divisible. Eh bien (dit le Sirien), cette chose qui te paroît être divisible, pésante, et grise, me dirois tu bien ce que c'est? Tu vois quelques attributs: mais le fond de la chose, le connois tu? Non, dit l'autre. Tu ne scais donc point ce que c'est que la matière." (Voltaire, Micromégas, c. 7.) "Le fond de la chose"--the Ding an sich--is nothing but the name itself, divested of every fraction of meaning: it is _titulus sine re_. But the name being familiar, and having been always used with a meaning, still appears invested with much of the old emotional associations, even though it has been stripped of all its meaning by successive acts of abstraction. If you subtract from four, 1 + 1 + 1 + 1, there will remain zero. But by abstracting, from the subject _man_, all its predicates, real and possible, you cannot reduce it to zero. The _name_ man always remains, and appears by old association to carry with it some meaning--though the meaning can no longer be defined. This illusion is well pointed out in a valuable passage of Cabanis (Du Degré de Certitude de la Médecine, p. 61):--