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

CONCERNING the real effences of corporeal fubftances, (to mention these only) there are, if I mistake not, two opinions. The one is of thofe, who ufing the word effence for they know not what, suppose 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 fpecies. The other and more rational opinion, is of thofe 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 diftinguish them one: from another, according as we have occafion to rank them into forts under common denominations. The former of thefe opinions, which fuppofes thefe effences, as a certain number of forms or moulds wherein all natural things, that exift, are caft, and do equally partake, has,, Limagine, very much perplexed the knowledge of natur al things. The frequent productions of monfters, in all the fpecies of animals, and of changelings, and other ftrange iffues of human birth, carry with them difficul-ties 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 two figures partaking of the fame real effence of a circle fhould have different properties. But were: there no other reafon against it, yet the fuppofition of ef fences that cannot be known, and the making them neverthelefs to be that which diftinguishes the fpecies of things is fo wholly ufelefs, and unferviceable to any part of our knowledge, that that alone were sufficient 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 elfe but thofe abstract complex ideas, to which we have annexed diftinct: general names.

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

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 fpace 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 infeparably annexed. But it is far otherwife 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 effences fince nothing can be called gold but what has a conformity of qualities to that abstract complex idea, to which that name is annexed. But this distinction of effences, belonging particularly to fubftances, we fhall, when we come to confider their names, have an occafion to treat of more fully.

§ 19. Effences ingenerable and incorruptible. THAT fuch abftract 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 perish with them. All things that exift, befides their author, are all liable to change; efpecially thofe 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 a 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 several things depended, is destroyed, and per ifhes with them. But effences being taken for ideas,

eftablished in the mind, with names annexed to them, they are fuppofed to remain fteadily 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 supposed nevertheless to remain the fame and fo the effences of those fpecies are preferved whole and undeftroyed, whatever changes happen to any, or all of the individuals of those Species. By this means, the effence of a fpecies refts fafe and entire, without the existence of so 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 ceafe to be as a pattern to determine which of 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 beaft as an unicorn, or such a fish as a mermaid; yet fuppofing those names to ftand for complex abftract 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 horse. 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.

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§ 20. Recapitulation.

To conclude, this is that which in fhort I would fay, vix. That all the great business of genera and fpecies, and their effences, amounts to no more but this, that men making atftract 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, Mades, and Substances, haver each fomething peculiar.

HOUGH all words, as I have flown, fignify noth-

Ting immediately but the ideas in the mind of

the speaker; yet upon a nearer furvey we fhall find that the names of fimple ideas, mixed modes (under which I comprife relations too) and natura! fubftances, have each." of them fomething peculiar and different from the other.. For example:

§ 2. 1. Names of fimple Ideas and Subftances intimate: real Exiftence.

FIRST, The names of fimple ideas and fubftances, with the abstract ideas in the mind, which they immediately fignify, intimate alfo fome real exiftence, from which was derived their original pattern. But the names of mixed modes terminate in the idea that is in the mind, and lead: not the thoughts any farther, as we fhall fee more at large in the following chapter.

$3, 2. Names of fimple Ideas, and Modes fignify al-ways both real and nominal Effence.

SECONDLY, The names of fimple ideas,and modes fignify always the real as well as nominal effence of their fpecies. But the names of natural fubftances fignify rarely, if ever,, any thing but barely the nominal effences of thofe fpecies, as we fhall fhow in the chapter that treats of the names of fubftances in particular.

§ 4. 3. Names of fimple Ideas undefinable. THIRDLY, The names of fimple ideas are not capable of any definitions; the names of all complex ideas are. It has not, that I know, been yet obferved by any body, what words are, and what are not capable of being defined; the want whereof is (as I am apt to think) not feldom the occafion of great wrangling and obfcurity in men's difcourfes, whilft fome demand definitions of terms that cannot be defined; and others think they ought to reft. fatisfied in an explication made by a more general word,

and its restriction (or to speak in terms of art, by a genus and difference) when even after fuch definition made according to rule, those who hear it, have often no more a clear conception of the meaning of the word than they had before. This at leaft I think, that the fhowing what words are, and what are not capable of definitions, and wherein confifts a good definition, is not wholly befides our prefent purpose; and perhaps willafford fo much light to the nature of thefe figns, and our ideas, as to deferve a more particular confideration. § 5. If all were definable it would be a procefs in infinitum I WILL not here trouble myself, to prove that all terms are not definable from that progress, in infinitum, which it will vifibly lead us into, if we should allow that all names could be defined. For if the terms of one definition were still to be defined by another, where at laft fhould we stop? But I fhall, from the nature of our ideas, and the fignification of our words, fhow, why foms names can and others cannot be defined, and which they are.. $6. What a definition is.

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I THINK it is agreed, that a definition is nothing else, but the fhowing the meaning of one word by feveral other not fynonimous terms. The meaning of words being only the ideas they are made to ftand for by him that ufes them the meaning of any term is then fhowed, or the word is defined, when by other words, the idea it is made the fign of, and annexed to in the mind of the fpeaker, is as it were reprefented, or fet before the view of another; and thus its fignification ascertained: this is the only use and end of definitions; and therefore the only measure of what is, or is not a good definition.

§ 7. Simple Ideas why undefinable:

THIS being premifed, I fay, that the names of fimple ideas and thofe only, are incapable of being defined. The reafon whereof is this, that the feveral terms of a definition, fignifying feveral ideas, they can all together by no means reprefent an idea, which has no compofition at all; and therefore a definition, which is properly nothing but the showing the meaning of one word by feveral others not fignifying each the fame thing, can in the names of fimple ideas have no place.