First, Essence may be taken for-the Being of anything, whereby it is what it is. And thus the real in-. ternal (but, generally in Substances, unknown) constitution of things, whereon their discoverable qualities depend, may be called their 'Essence.' This is the proper, original signification of the word, as is evident from the formation of it; essentia, in its primary notation, signifying properly being.' And in this sense it is still used when we speak of the Essence of particular things without giving them any name.

Secondly, The learning and disputes of the Schools having been much busied about genus and species, the word Essence has almost lost its primary signification; and, instead of the real constitution of things, has been almost wholly applied to the artificial constitution of genus and species. It is true, there is ordinarily supposed a real constitution of the sorts of things: and it is past doubt there must be some real constitution, on which any collection of simple ideas co-existing must depend. But it being evident that things.are ranked under names into sorts or species only as they agree to certain Abstract Ideas to which we have annexed those names, the Essence of each genus or sort comes to be nothing but that Abstract Idea, which the general or 'sortal' (if I may so call it from "sort," as I do 'general' from "genus ") name stands for. And this we shall find to be that which the word Essence imports in its most familiar use. These two sorts of Essences, I suppose, may not unfitly be termed, the one the Real, the other the Nominal Essence.

Constant connexion between the name and nominal es

sence. Between the Nominal Essence and the name there is so near a connexion, that the name of any sort of things cannot be attributed to any particular being but [that which] has this Essence, whereby it answers that Abstract Idea whereof that name is the sign.

Supposition that species are distinguished by their real essences useless.—Concerning the Real Essences of corporeal Substances (to mention those only) there are, if I mistake not, two opinions. [1.] The one is of those who, using the word Essence for they know not what, suppose a certain number of those Essences, according to which all natural things are made, and wherein they do exactly every one of them partake, and so become of this or that species. [2.] The other and more rational opinion is of those who look on all natural things to have a real, but unknown Constitution of their insensible parts, from which flow those sensible Qualities which serve us to distinguish them one from another, according as we have occasion to rank them into sorts under common denominations. The former of these opinions has, I imagine, very much perplexed the knowledge of natural things. The frequent productions of monsters, in all the species of animals, and of changelings, and other strange issues of human birth, carry with them difficulties not possible to consist with this hypothesis: since it is as impossible that two things, partaking exactly of the same Real Essence, should have different properties, as that two Figures partaking of the same Real Essence of a circle should have different properties. But were there no other reason against it, yet the supposition of Essences that cannot be known—and the making them neverthe

less to be that which distinguishes the species of things-is so wholly useless and unserviceable to any part of our Knowledge, that that alone were sufficient to make us lay it by, and content ourselves with such Essences of the sorts or species of things as come within the reach of our Knowledge: which, when seriously considered, will be found, as I have said, to be nothing else but those Abstract Complex Ideas to which we have annexed distinct general names..

Real and nominal essences, the same in simple ideas and modes, different in substances.-Essences being thus distinguished into Nominal and Real, we may farther observe, that in the species of Simple ideas and Modes, they are always the same: butin Substances, always quite different. Thus a Figure including a space between three lines is the real as well as nominal Essence of a triangle: it being not only the Abstract Idea to which the general name is annexed, but the very essentia—or 'being,' of the thing itself,-that foundation from which all its properties flow, and to which they are all inseparably annexed. But it is far otherwise concerning that parcel of matter which makes the ring on my finger, wherein these two Essences are apparently different. For it is the real constitution of its insensible parts -on which depend all those properties of colour, weight, fusibility, fixedness, &c.-which makes it to be gold, or gives it a right to that name, [and] which is therefore its Nominal Essence; since nothing can be called gold but what has a conformity of qualities to that Abstract Complex Idea, to which that name is annexed.

Essences ingenerable and incorruptible. That such Ab

stract Ideas with names to them, as we have been speaking of, are Essences, may farther appear by what we are told concerning Essences; viz, that they are all ingenenerable and incorruptible. Which cannot be true of the real constitutions of things, which begin and perish with them. All things that exist, [except] their Author, are liable to change; especially those things we are acquainted with, and have ranked into bands, under distinct names or ensigns. Thus, that which was grass to-day is to-morrow the flesh of a sheep; and, within few days after, becomes part of a man; in all which and the like changes, it is evident their real Essence, i. e. that constitution whereon the properties of these several things depended, is destroyed, and perishes with them. But Essences being taken for ideas established in the mind, with names annexed to them, they are supposed to remain steadily the same, whatever mutations the particular substances are liable to. For whatever becomes of Alexander and Bucephalus, the ideas to which 'man' and 'horse' are annexed are supposed, nevertheless, to remain the same; and so the Essences of those species are preserved whole and undestroyed, whatever changes happen to any or all of the individuals of those species. By th[ese] means the Essence of a species rests safe and entire, without the existence of so much as one individual of that kind. For were there now no circle existing anywhere in the world (as, perhaps, that figure exists not anywhere exactly marked out), yet the idea annexed to that name would not cease to be what it is; nor cease to be as a pattern, to determine which of the particular figures we meet with, has, or has not, a

right to the name 'circle,' and so to show which of them, by having that Essence [is] of that species. And though there neither were, nor had been, in nature such a beast as a unicorn,' or such a fish as a 'mermaid,' yet, supposing those names to stand for Complex Abstract Ideas, that contained no inconsistency in them, the Essence of a 'mermaid' is as intelligible as that of a 'man;’ and the idea of a 'unicorn,' as certain, steady, and permanent as that of a 'horse.' From what has been said, it is evident, that the doctrine of the immutability of Essences proves them to be only Abstract Ideas; and is founded on the relation established between them, and certain sounds as signs of them; and will always be true, as long as the same name can have the same signification.

CHAPTER IV.

OF THE NAMES OF SIMPLE IDEAS.

Names of simple ideas, modes, and substances, have each something peculiar.-Though all Words, as I have shown, signify nothing immediately but the ideas in the mind of the speaker, yet, upon a nearer survey, we shall find that the names of Simple Ideas, Mixed Modes (under which I comprise Relations, too), and Natural Substances, have each of them something peculiar and different from the other. For example:—

Names of simple ideas and substances intimate real existence. First, The names of Simple Ideas and Sub