354 ON HUMAN UNDERSTANDING 



And, first, of complex ideas of COMBINATION. Unity, as I have already observed, 

 is a simple idea : and it is one of the most common simple ideas that can be 

 presented to the mind, for every object without, and every idea within, tend 

 equally to excite it. And, as being a simple idea, the mind, as I have also 

 remarked, is passive on its presentation ; it can neither form such an idea to 

 itself, nor contemplate it otherwise than in its totality: but it can combine 

 the ideas of as many units as it pleases, and hence produce the complex idea 

 of a hundred, a thousand, or a hundred thousand. So beauty is a complex 

 idea ; for the mind, in forming it, combines a variety of separate ideas into 

 one common aggregate. Thus Dry den, in delineating the beautiful Victoria, 

 in his " Love Triumphant :" 



Her eyes, her lips, her cheeks, her shape, her features, 

 Seem to be drawn by LOVE'S own hand ; by LOVK 

 Himself in love. 



In like manner the mind can produce complex ideas by an opposite process, 

 and that is, by ABSTRACTION, or separation. Thus chalk, snow, and milk, though 

 agreeing, perhaps, in no other respect, coincide in the same colour ; and the 

 mind, contemplating this agreement, may abstract or separate it from the 

 other properties of these three objects, and form the idea which is indicated 

 by the term whiteness; and having thus acquired a new idea by the process 

 of abstraction, it may afterward apply it as a character to a variety of other 

 objects: and hence particular ideas become general or universal. 



Other complex ideas are produced by COMPARISON. Thus, if the mind take 

 one idea, as that of a foot, as a determinate measure, and place it by the 

 side of another idea, as the idea of a table, ther result will be a formation of 

 the complex idea of length, breadth, and thickness. Or if we vary the pri- 

 mary ideas, we may obtain as a result the secondary ideas of coarseness and 

 fineness. 



And hence, complex ideas must be almost infinitely more numerous than 

 simple ideas, which are their elements or materials, as words must be always 

 far more numerous than letters. I have instanced only a few of their prin- 

 cipal kinds ; but even each of these kinds is applicable to a variety of subjects, 

 of which Mr. Locke mentions the three following: 



I. IDEAS OF SUBSTANCES ; or such as we have uniformly found connected in 

 the same thing, and without which, therefore, such thing cannot be contem- 

 plated. To this head belong the complex ideas of a man, a horse, a river, a 

 mountain. 



II. IDEAS OF MODES ; 05 such as may be considered as representative of the 

 mere affections, or properties of substance ; of which the idea of number 

 may once more be offered as an example : the ideas of expansion or exten- 

 sion and duration belong to the same stock ; and in like manner those of 

 power, time, space, and infinity, which are all modes, properties, or affections 

 of substance ; or secondary ideas derived from or excited by the primary idea 

 of substance of some kind or other. 



III. IDEAS OF RELATIONS; which are by far the most extensive, if not the 

 most important, branch of subjects from which our complex ideas are derived ; 

 for there is nothing whatever, whether simple idea, substance, mode, relation, 

 or even the name of any of them, which is not capable of an almost infinite num- 

 ber of bearings in reference or relation to other things. It is from this source, 

 therefore, that we derive a very large proportion of our thoughts and words. 

 As examples under it, I may mention all those ideas that relate to or are even 

 imported by the terms father, brother, son, master, magistrate, younger, older, 

 cause and effect, right and wrong, and, consequently, all moral relations. 



It must hence appear obvious that many of our ideas have a NATURAL COR- 

 RESPONDENCE, congruity, and connexion with each other. And as many, per- 

 haps, on the contrary, a NATURAL REPUGNANCY, incongruity, and disconnexion. 

 Thus if I were to speak of a cold fire, I should put together ideas that are 

 naturally disconnected and incongruous, and should consequently make an 

 absurd proposition, or, to adopt common language, talk nonsense. I should 



