where their abstract ideas feem to be taken from the things themselves, they are not conftantly the fame, no, not in that species which is most familiar to us, and with which we have the most intimate acquaintance; it having been more than once doubted, whether the fætus born of a woman were a man, even so far as that it hath been debated, whether it were or were not to be nourished and baptized; which could not be, if the abstract idea of effence, to which the name man belonged, were of nature's making, and were not the uncertain and various collection of fimple ideas which the understanding puts together, and then abstracting it, affixed a name to it; fo that in truth every diftinct abftract idea is a diftinct effence, and the names that ftand for fuch diftinct ideas, are the names of things effentially different. Thus, a circle is as effentially different from an oval as a sheep from a goat, and rain is as effentially different from fnow as water from earth; that abstract idea which is the effence of one being impoffible to be communicated to the other. And thus any two abstract ideas, that in any part vary one from another, with two diftinct names annexed to them, conftitute two dif tinct forts, or, if you please, fpecies, as effentially dif ferent as any two the most remote or oppofite in the world.

15. Real and Nominal Effence.

BUT fince the effences of things are thought by fome (and not without reafon) to be wholly unknown, it may not be amifs to confider the feveral fignifications of the word effence.

First, Effence may be taken for the being of any thing, whereby it is what it is; and thus the real internal, but generally in fubftances unknown, conftitution of things, whereon their difcoverable qualities depend, may be called their effence. This is the proper original fignification of the word, as is evident from the formation of it; effentia, in its primary notation, fignifying properly being: And in this sense it is still used, when we fpeak of the effence of particular things, without giving them any name.

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Secondly, The learning and difputes of the fchools having been much bufied about genus and fpecies, the word effence has almost loft its primary fignification; and instead of the real conftitution of things, has been almost wholly applied to the artificial conftitution of genus and fpecies. It is true, there is ordinarily fuppofed a real constitution of the forts of things, and it is paft doubt there must be fome real conftitution on which any collection of fimple ideas co-existing must depend. But it being evident, that things are ranked under names into forts or fpecies, only as they agree to certain abstract ideas, to which we have annexed thofe names, the ef fence of each genus or fort comes to be nothing but that abstract idea, which the general or fortal (if I may have leave fo to call it from fort, as I do general from genus) name ftands for; and this we fhall find to be that which the word effence imports in its most familiar ufe. These two forts of effences, I fuppofe, may not unfitly be termed, the one the real, the other the nominal effence.

16. Conflant Connection between the name and nominal Effence.

BETWEEN the nominal effence and the name, there is fo near a connection, that the name of any fort of things cannot be attributed to any particular being but what has this effence, whereby it answers that abstract idea, whereof that name is the fign.

17. Suppofition that Species are diftinguished by their real Effences, useless.

CONCERNING the real effences of corporeal fubftances (to mention those only), there are, if I mistake not, two opinions. The one is of thofe, who, using the word effence for they know not what, fuppofe a certain number of thofe effences, according to which all natural things are made, and wherein they do exactly every one of them partake, and fo become of this or that /pecies. The other and more rational opinion, is of those who look on all natural things to have a real but unknown conftitution of their infenfible parts, from which flow those fenfible qualities which ferve us to distinguish them one

from another, according as we have occafion to rank them into forts under common denominations. The former of these opinions, which fuppofes these effences as a certain number of forms or moulds, wherein all natural things that exift are caft, and do equally partake, has, I imagine, very much perplexed the knowledge of natural things. The frequent productions of monsters, in all the fpecies of animals, and of changelings, and other ftrange iffues of human birth, carry with them difficulties not poffible to confift with this hypothefis; fince it is as impoffible that two things, partaking exactly of the fame real effence, fhould have different properties, as that the two figures partaking in the fame real effence of a circle should have different properties. But were there no other reafon against it, yet the fuppofition of effences that cannot be known, and the making them nevertheless to be that which distinguishes the fpecies of things, is fo wholly useless and unferviceable to any part of our knowledge, that that alone were fufficient to make us lay it by, and content ourselves with fuch effences of the forts or fpecies of things as come within the reach of our knowledge, which, when seriously confidered, will be found, as I have faid, to be nothing else but those abstract complex ideas, to which we have annexed distinct general names.

§ 18. Real and nominal Effence the fame in fimple Ideas and Modes, different in Subftances.

ESSENCES being thus diftinguished into nominal and real, we may farther obferve, that in the fpecies of fimple ideas and modes they are always the fame, but in fubftances always quite different. Thus, a figure including a space between three lines, is the real as well as nominal effence of a triangle, it being not only the abstract idea to which the general name is annexed, but the very effentia 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 effences are apparently different; for it is the real conftitution of its infenfible parts on which

depend all those properties of colour, weight, fufibility, fixednefs, &c. which makes it to be gold, or gives it a right to that name, which is therefore its nominal effence; fince nothing can be called gold but what has a conformity of qualities to that abftract complex idea to which that name is annexed. But this diftinction of effences, belonging particularly to fubftances, we fhall, when we come to confider their names, have an occasion to treat of more fully.

$19. Effences ingenerable and incorruptible.

THAT fuch abstract ideas, with names to them, as we have been fpeaking of, are effences, may farther appear by what we are told concerning effences, viz. that they are all ingenerable and incorruptible; which cannot be true of the real conftitutions of things which begin and perifh with them. All things that exift, befides their author, are all liable to change; efpecially those things we are acquainted with, and have ranked into bands under diftinct names or enfigns. Thus that which was grafs 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 effence, i. e. that conftitution whereon the properties of these feveral things depended, is deftroyed, and perifhes with them. But effences being taken for ideas established in the mind, with names annexed to them, they are supposed to remain steadily the fame, whatever mutations the particular fubftances are liable to; for whatever becomes of Alexander and Bucephalus, the ideas to which man and horfe are annexed, are fuppofed neverthelefs to remain in the fame; and fo the fences of thofe fpecies are preserved whole and undeftroyed, whatever changes happen to any, or all of the individuals of those fpecies. By this means, the effence of a species refts fafe and entire, without the existence of fo much as one individual of that kind: For were there now no circle exifting any where in the world (as perhaps that figure exifts not any where 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

149 the particular figures we meet with have or have not a right to the name circle, and fo to fhow which of them, by having that effence, was of that species. And though there neither were nor had been in nature such a beast as an unicorn, or fuch a fish as a mermaid; yet fuppofing those names to ftand for complex abstract ideas that contained no inconfiftency in them, the effence of a mermaid is as intelligible as that of a man, and the idea of an unicorn as certain, fteady and permanent as that of a horfe. From what has been faid, it is evident, that the doctrine of the immutability of effences proves them to be only abstract ideas; and is founded on the relation established between them and certain founds as figns of them, and will always be true as long as the fame name can have the fame fignification.

$20. Recapitulation.

To conclude, this is that which in fhort I would say, viz. That all the great bufinefs of genera and Species, and their effences, amounts to no more but this; that men making abstract ideas, and fettling them in their minds with names annexed to them, do thereby enable themselves to confider things, and difcourfe of them, as it were in bundles, for the easier and readier improvement and communication of their knowledge; which would advance but flowly, were their words and thoughts confined only to particulars.

CHAP. IV.

OF THE NAMES OF SIMPLE IDEAS.

1. Names of fimple Ideas, Modes and Subftances, have each fomething peculiar.

HOUGH all words, as I have fhown, fignify nothing immediately but the ideas in the mind of the speaker; yet upon a nearer furvey we shall find that the names of fimple ideas, mixed modes (under which I comprife relations too), and natural fubftances, and each of them, have fomething peculiar and different from the other.. For example: