# An Essay Concerning Human Understanding/Book II/Chapter XXV

1. Relation, what. Besides the ideas, whether simple or complex, that the mind has of things as they are in themselves, there are others it gets from their comparison one with another. The understanding, in the consideration of anything, is not confined to that precise object : it can carry an idea as it were beyond itself, or at least look beyond it, to see how it stands in conformity to any other. When the mind so considers one thing, that it does as it were bring it to, and set it by another, and carries its view from one to the other – this is, as the words import, relation and respect ; and the denominations given to positive things, intimating that respect, and serving as marks to lead the thoughts beyond the subject itself denominated to something distinct from it, are what we call relatives ; and the things so brought together, related. Thus, when the mind considers Caius as such a positive being, it takes nothing into that idea but what really exists in Caius ; v.g. when I consider him as a man, I have nothing in my mind but the complex idea of the species, man. So likewise, when I say Caius is a white man, I have nothing but the bare consideration of a man who hath that white colour. But when I give Caius the name husband, I intimate some other person ; and when I give him the name whiter, I intimate some other thing : in both cases my thought is led to something beyond Caius, and there are two things brought into consideration. And since any idea, whether simple or complex, may be the occasion why the mind thus brings two things together, and as it were takes a view of them at once, though still considered as distinct : therefore any of our ideas may be the foundation of relation. As in the above-mentioned instance, the contract and ceremony of marriage with Sempronia is the occasion of the denomination and relation of husband ; and the colour white the occasion why he is said to be whiter than free-stone.
2. Ideas of relations without correlative terms, not easily apprehended. These and the like relations, expressed by relative terms that have others answering them, with a reciprocal intimation, as father and son, bigger and less, cause and effect, are very obvious to every one, and everybody at first sight perceives the relation. For father and son, husband and wife, and such other correlative terms, seem so nearly to belong one to another, and, through custom, do so readily chime and answer one another in people’s memories, that, upon the naming of either of them, the thoughts are presently carried beyond the thing so named ; and nobody overlooks or doubts of a relation, where it is so plainly intimated. But where languages have failed to give correlative names, there the relation is not always so easily taken notice of. Concubine is, no doubt, a relative name, as well as a wife : but in languages where this and the like words have not a correlative term, there people are not so apt to take them to be so, as wanting that evident mark of relation which is between correlatives, which seem to explain one another, and not to be able to exist, but together. Hence it is, that many of those names, which, duly considered, do include evident relations, have been called external denominations. But all names that are more than empty sounds must signify some idea, which is either in the thing to which the name is applied, and then it is positive, and is looked on as united to and existing in the thing to which the denomination is given ; or else it arises from the respect the mind finds in it to something distinct from it, with which it considers it, and then it includes a relation.
3. Some seemingly absolute terms contain relations. Another sort of relative terms there is, which are not looked on to be either relative, or so much as external denominations : which yet, under the form and appearance of signifying something absolute in the subject, do conceal a tacit, though less observable, relation. Such are the seemingly positive terms of old, great, imperfect, &c., whereof I shall have occasion to speak more at large in the following chapters.
4. Relation different from the things related. This further may be observed, That the ideas of relation may be the same in men who have far different ideas of the things that are related, or that are thus compared : v.g. those who have far different ideas of a man, may yet agree in the notion of a father ; which is a notion superinduced to the substance, or man, and refers only to an act of that thing called man whereby he contributed to the generation of one of his own kind, let man be what it will.
5. Change of relation may be without any change in the things related. The nature therefore of relation consists in the referring or comparing two things one to another ; from which comparison one or both comes to be denominated. And if either of those things be removed, or cease to be, the relation ceases, and the denomination consequent to it, though the other receive in itself no alteration at all : v.g. Caius, whom I consider to-day as a father, ceases to be so to-morrow, only by the death of his son, without any alteration made in himself. Nay, barely by the mind’s changing the object to which it compares anything, the same thing is capable of having contrary denominations at the same time : v.g. Caius, compared to several persons, may be truly be said to be older and younger, stronger and weaker, &c.
6. Relation only betwixt two things. Whatsoever doth or can exist, or be considered as one thing is positive : and so not only simple ideas and substances, but modes also, are positive beings : though the parts of which they consist are very often relative one to another : but the whole together considered as one thing, and producing in us the complex idea of one thing, which idea is in our minds, as one picture, though an aggregate of divers parts, and under one name, it is a positive or absolute thing, or idea. Thus a triangle, though the parts thereof compared one to another be relative, yet the idea of the whole is a positive absolute idea. The same may be said of a family, a tune, &c. ; for there can be no relation but betwixt two things considered as two things. There must always be in relation two ideas or things, either in themselves really separate, or considered as distinct, and then a ground or occasion for their comparison.
7. All things capable of relation. Concerning relation in general, these things may be considered :
First, That there is no one thing, whether simple idea, substance, mode, or relation, or name of either of them, which is not capable of almost an infinite number of considerations in reference to other things : and therefore this makes no small part of men’s thoughts and words : v.g. one single man may at once be concerned in, and sustain all these following relations, and many more, viz. father, brother, son, grandfather, grandson, father-in-law, son-in-law, husband, friend, enemy, subject, general, judge, patron, client, professor, European, Englishman, islander, servant, master, possessor, captain, superior, inferior, bigger, less, older, younger, contemporary, like, unlike, &c., to an almost infinite number : he being capable of as many relations as there can be occasions of comparing him to other things, in any manner of agreement, disagreement, or respect whatsoever. For, as I said, relation is a way of comparing or considering two things together, and giving one or both of them some appellation from that comparison ; and sometimes giving even the relation itself a name.
8. Our ideas of relations often clearer than of the subjects related. Secondly, This further may be considered concerning relation, that though it be not contained in the real existence of things, but something extraneous and superinduced, yet the ideas which relative words stand for are often clearer and more distinct than of those substances to which they do belong. The notion we have of a father or brother is a great deal clearer and more distinct than that we have of a man ; or, if you will, paternity is a thing whereof it is easier to have a clear idea, than of humanity ; and I can much easier conceive what a friend is, than what God ; because the knowledge of one action, or one simple idea, is oftentimes sufficient to give me the notion of a relation ; but to the knowing of any substantial being, an accurate collection of sundry ideas is necessary. A man, if he compares two things together, can hardly be supposed not to know what it is wherein he compares them : so that when he compares any things together, he cannot but have a very clear idea of that relation. The ideas, then, of relations, are capable at least of being more perfect and distinct in our minds than those of substances. Because it is commonly hard to know all the simple ideas which are really in any substance, but for the most part easy enough to know the simple ideas that make up any relation I think on, or have a name for : v.g. comparing two men in reference to one common parent, it is very easy to frame the ideas of brothers, without having yet the perfect idea of a man. For significant relative words, as well as others, standing only for ideas ; and those being all either simple, or made up of simple ones, it suffices for the knowing the precise idea the relative term stands for, to have a clear conception of that which is the foundation of the relation ; which may be done without having a perfect and clear idea of the thing it is attributed to. Thus, having the notion that one laid the egg out of which the other was hatched, I have a clear idea of the relation of dam and chick between the two cassiowaries in St. James’s Park ; though perhaps I have but a very obscure and imperfect idea of those birds themselves.
9. Relations all terminate in simple ideas. Thirdly, Though there be a great number of considerations wherein things may be compared one with another, and so a multitude of relations, yet they all terminate in, and are concerned about those simple ideas, either of sensation or reflection, which I think to be the whole materials of all our knowledge. To clear this, I shall show it in the most considerable relations that we have any notion of ; and in some that seem to be the most remote from sense or reflection : which yet will appear to have their ideas from thence, and leave it past doubt that the notions we have of them are but certain simple ideas, and so originally derived from sense or reflection.
10. Terms leading the mind beyond the subject denominated, are relative. Fourthly, That relation being the considering of one thing with another which is extrinsical to it, it is evident that all words that necessarily lead the mind to any other ideas than are supposed really to exist in that thing to which the words are applied are relative words : v.g. a man, black, merry, thoughtful, thirsty, angry, extended ; these and the like are all absolute, because they neither signify nor intimate anything but what does or is supposed really to exist in the man thus denominated ; but father, brother, king, husband, blacker, merrier, &c., are words which, together with the thing they denominate, imply also something else separate and exterior to the existence of that thing.
11. All relatives made up of simple ideas. Having laid down these premises concerning relation in general, I shall now proceed to show, in some instances, how all the ideas we have of relation are made up, as the others are, only of simple ideas ; and that they all, how refined or remote from sense soever they seem, terminate at last in simple ideas. I shall begin with the most comprehensive relation, wherein all things that do, or can exist, are concerned, and that is the relation of cause and effect : the idea whereof, how derived from the two fountains of all our knowledge, sensation and reflection, I shall in the next place consider.