made those names the signs? And what are the essences of those species, set out and marked by names, but those abstract ideas in the mind; which are, as it were, the bonds between particular things that exist, and the names they are to be ranked under? and when general names have any connexion with particular beings, these abstract ideas are the medium that unites them; so that the essences of species, as distinguished and denominated by us, neither are, nor can be, any thing but these precise abstract ideas we have in our minds. And, therefore, the supposed real essences of substances, if different from our abstract ideas, cannot be the essences of the species we rank things into. For two species may be one, as rationally as two different essences be the essence of one species; and I demand, what are the alterations may, or may not, be in a horse or lead, without making either of them to be of another species? In determining the species of things by our abstract ideas, this is easy to resolve; but if any one will regulate himself herein, by supposed real essences, he will, I suppose, be at a loss: and he will never be able to know when any thing precisely ceases to be of the species of a horse or lead. §14. Each distinct abstract idea is a distinct essence.-Nor will any one wonder, that I say these essences, or abstract ideas (which are the measures of name, and the boundaries of species), are the workmanship of the understanding, who considers that at least the complex ones are often, in several men, different collections of simple ideas; and therefore, that is covetousness to one man, which is not so to another. Nay, even in substances, where their abstract ideas seem to be taken from the things themselves, they are not constantly the same; 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 foetus born of a woman, were a man, even so far that it hath been debated, whether it were, or were not to be nourished and baptized; which could not be, if the abstract idea, or essence, to which the name man belonged, were of nature's making and were not the uncertain and various collection of simple ideas, which the understanding puts together, and then abstracting it, affixed a name to it. So that, in truth, every distinct abstract idea, is a distinct essence: and the names that stand for such distinct ideas, are the names of things essentially different. Thus a circle is as essentially different from an oval, as a sheep from a goat; and rain is as essentially different from snow, as water from earth; that abstract idea, which is the essence of one, being impossible to be communicated to the other. And thus any two abstract ideas, that in any part vary one from another, with two distinct names annexed to them, constitute two distinct sorts, or, if you please, species, as essentially different as any two the most remote or opposite in the world. 15. Real and nominal essences.-But since the essences of things are thought by some (and not without reason) to be wholly unknown; it may not be amiss to consider the several significations of the word essence. First, Essence may be taken for the being of any thing, whereby it is what it is. And thus, the real internal, 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 have leave so to 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. - § 16. Constant connexion between the name and nominal essence.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 what has this essence, whereby it answers that abstract idea, whereof that name is the sign. § 17. Supposition that species are distinguished by their real essences, useless.-Concerning the real essences of corporeal substances (to mention these only), there are, if I mistake not, two opinions. 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. 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, which supposes these essences as a certain number of forms or moulds, wherein all natural things, that exist, are cast, and do equally partake, 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, nevertheless, 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. § 18. Real and nominal essence, 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; but in 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, which is therefore its nomi nal 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. But this distinction of essences, belonging particularly to substances, we shall, when we come to consider their names, have an occasion to treat of more fully. § 19. Essences ingenerable and incorruptible.-That such abstract 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 ingenerable and incorruptible. Which cannot be true of the real constitutions of things, which begin and perish with them. All things that exist, besides their author, are all 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 a 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 this 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 any where in the world (as, perhaps, that figure exists 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 the particular figures we meet with, have, or have not, a right to the name circle, and so to shew which of them, by having that essence, was of that species. And though there neither were, nor had been in nature such a beast as an unicorn, nor 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 an 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 a cnhave the same signification. § 20. Recapitulation.-To conclude, this is that which in short I would say, viz. that all the great business of genera and species, and their essences, amounts to no more but this, that men making abstract ideas, and settling them in their minds, with names annexed to them, do thereby enable themselves to consider things, and discourse of them, as it were, in bundles, for the easier and readier improvement and communication of their knowledge, which would advance but slowly, were their words and thoughts confined only to particulars. CHAP. IV. OF THE NAMES OF SIMPLE IDEAS. § 1. Names of simple ideas, modes, and substances, have each something peculiar.-Though all words, as I have shewn, 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: § 2. First, names of simple ideas and substances, intimate real existence. First, The names of simple ideas and substances, with the abstract ideas in the mind, which they immediately signify, intimate also some real existence, 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 shall see more at large in the following chapter. §3. Secondly, names of simple ideas and modes, signify always both real and nominal essence.-Secondly, The names of simple ideas and modes, signifying always the real, as well as nominal, essence of their species. But the names of natural substances signify rarely, if ever, any thing but barely the nominal essences of those species, as we shall shew in the chapter that treats of the names of substances in particular. §4. Thirdly, names of simple ideas undefinable.-Thirdly, The names of simple ideas are not capable of any definitions; the names of all complex ideas are. It has not, that I know, hitherto been taken notice of 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 seldom the occasion of great wrangling and obscurity in men's discourses, whilst some demand definitions of terms that cannot be defined; and others think, they ought to rest satisfied 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 such definition made according to rule, those who hear of it, have often no more a clear conception of the meaning of the word, than they had before. This at least, I think, that the shewing what words are, and what are not, capable of definitions, and wherein consists a good definition, is not wholly beside our present purpose; and perhaps will afford so much light to the nature of these signs, and our ideas, as to deserve a more particular consideration. 5. If all were definable, it would be a process in infinitum.—I will not here trouble myself, to prove that all terms are not definable from that progress, in infinitum, which it will visibly 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 last should we stop? But I shall, from the nature of our ideas, and the signification of our words, shew, why some names can, and others cannot, be defined, and which they are. § 6. What a definition is.-I think it is agreed, that a definition is nothing else, but the shewing the meaning of one word by several other not synonymous terms. The meaning of words, being only the ideas they are made to stand for by him that uses them; the meaning of any term is then shewn, or the word is defined, when by other words the idea it is made the sign of, and annexed to in the mind of the speaker, is, as it were, represented, or set before the view of another; and thus its signification 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 premised, I say, that the names of simple ideas, and those only, are incapable of being defined. The reason whereof is this, that the several terms of a definition, signifying several ideas, they can altogether by no means represent an idea, which has no composition at all; and therefore definition, which is properly nothing but the shewing the meaning of one word by several others, not signifying each the same thing, can in the names of simple ideas have no place. § 8. Instances; motion. The not observing this difference in our ideas, and their names, has produced that eminent trifling in the schools, which is so easy to be observed in the definitions they give us of some few of these simple ideas. For as to the greatest part of them, even those masters of definitions were fain to leave them untouched, merely by the impossibility they found in it. What more exquisite jargon could the wit of man invent, than this definition, "The act of a being in power, as far forth as in power?" which would puzzle any rational man, to whom it was not already known by its famous absurdity, to guess what word it could ever be supposed to be the explication of. If Tully, asking a Dutchman what beweeginge was, should have received this explication in his own language, that it was actus entis in potentia quatenus in potentia; I ask whether any one can imagine he could thereby have under |