108. This implies the degradation of the ‘primary qualities of body’ from the position which they hold in the Second Book of the Essay, as the real, par excellence, to that of a nominal essence. In the Second Book, just as the complex of ideas, received and to be received from a substance, is taken for the real thing without disturbance from the antithesis between reality and ‘ideas in the mind,’ so the primary qualities of body are taken not only as real, but as the sources of all other reality. Body, the real thing, copying itself upon the mind in an idea of sensation (that of solidity), carries with it from reality into the mind those qualities which ‘the mind finds inseparable from it,’ with all their modes. ‘A piece of manna of a sensible bulk is able to produce in us the idea of a round or square figure, and, by being removed from one place to another, the idea of motion. This idea of motion represents it, as it really is in the manna, moving; a circle or square are the same, whether in idea or existence, in the mind or in the manna; and this both motion and figure are really in the manna, whether we take notice of them or no.’ (Book II. chap. viii. sec. 18.) To the unsophisticated man, taking for granted that the ‘sensible bulk’ of the manna is a ‘real essence,’ this statement will raise no difficulties. But when he has learnt from Locke himself that the ‘sensible bulk,’ so far as we can think and speak of it, must consist in the ideas which it is said to produce, the question as to the real existence of these must arise. It turns out that they ‘really exist,’ so far as they represent the impact of a body copying itself in actually present sensation, and that from their reality, accordingly, must be excluded all qualities that accrue to the present sensation from its relation to the past. Can the ‘primary qualities’ escape this exclusion?
Are the ‘primary qualities’ then, a ‘nominal essence’?
109. To obtain a direct and compendious answer to this question from Locke’s own mouth is not easy, owing to the want of adjustment between the several passages where he treats of the primary qualities. They are originally enumerated as the ‘bulk, figure, number, situation, and motion or rest of the solid parts of bodies’ (Book II. chap. viii. sec. 23), and, as we have seen, are treated as all involved in that idea of solidity which is given in the sensation of touch. We have no further account of them till we come to the chapters on ‘simple modes of space and duration’ (Book II. chaps. xiii. &c.), which are introduced by the remark, that in the previous part of the book simple ideas have been treated ‘rather in the way that they come into the mind than as distinguished from others more compounded.’ As the simple idea, according to Locke, is that which comes first into the mind, the two ways of treatment ought to coincide; but there follows an explanation of the simple modes in question, of which to a critical reader the plain result is that the idea of body, which, according to the imaginary theory of ‘the way that it came into the mind’ is simple and equivalent to the sensation of touch, turns out to be a complex of relations of which the simplest is called space.
According to Locke’s account they are relations, and thus inventions of the mind.
110. To know what space itself is, ‘we are sent to our senses’ of sight and touch. It is ‘as needless to go to prove that men perceive by their sight a distance between bodies of different colours, or between the parts of the same body, as that they see colours themselves; nor is it less obvious that they can do so in the dark by feeling and touch.’ (Book II. chap. xiii. sec. 2.) Space being thus explained by reference to distance, and distance between bodies, it might be supposed that distance and body were simpler ideas. In the next paragraph, however, distance is itself explained to be a mode of space. It is ‘space considered barely in length between any two beings,’ and is distinguished (a) from ‘capacity’ or ‘space considered in length, breadth, and thickness;’ (b) from ‘figure, which is nothing but the relation which the parts of the termination of extension, or circumscribed space, have among themselves;’ (c) from ‘place, which is the relation of distance between anything and any two or more points which are considered as keeping the same distance one with another, and so as at rest.’ It is then shown at large (Book II. chap. xiii. sec. 11), as against the Cartesians, that extension, which is ‘space in whatsoever manner considered,’ is a ‘distinct idea from body.’ The ground of the distinction plainly lies in the greater complexity of the idea of body. Throughout the definition just given ‘space’ is presupposed as the simpler idea of which capacity, figure, and place are severally modifications; and these again, as ‘primary qualities,’ though with a slight difference of designation, [1] are not only all declared inseparable from body, but are involved in it under a further modification as ‘qualities of its solid parts’ i.e., of parts so related to each other that each will change its place sooner than admit another into it. (Book II. chap. iv. sec. 2, and chap. viii. sec. 23.) Yet, though body is thus a complex of relations—all, according to Locke’s doctrine of relation, inventions of the mind—and though it must be proportionately remote from the simple idea which ‘comes first into the mind,’ yet, on the other hand, it is in body, as an object previously given, that these relations are said to be found, and found by the senses. (Book II. chap. xiii. secs. 2, 27.) [2]
[1] In the enumeration of primary qualities, ‘capacity’ is represented by ‘bulk,’ ‘place’ by ‘situation.’
[2] In the second of the passages referred to, it will be seen that ‘matter’ is used interchangeably with ‘body.’
Body is the complex in which they are found. Do we derive the idea of body from primary qualities, or the primary qualities from idea of body?
111. It will readily be seen that ‘body’ here is a mode of the idea of substance, and, like it, [1] appears in two inconsistent positions as at once the beginning and the end of the process of knowledge—as on the one hand that in which ideas are found and from which they are abstracted, and on the other hand that which results from their complication. As the attempt either to treat particular qualities as given and substance as an abstraction gradually made, or conversely to treat the ‘thing’ as given, and relations as gradually superinduced, necessarily fails for the simple reason that substance and relations each presuppose the other, so body presupposes the primary qualities as so many relations which form its essence or make it what it is, while these again presuppose body as the matter which they determine, It is because Locke substitutes for this intellectual order of mutual presupposition a succession of sensations in time, that he finds himself in the confusion we have noticed—now giving the priority to sensations in which the idea of body is supposed to be conveyed, and from it deriving the ideas of the primary qualities, now giving it to these ideas themselves, and deriving the idea of body from their complication. This is just such a contradiction as it would be to put to-day before yesterday. We may escape it by the consideration that in the case before us it is not a succession of sensations in time that we have to do with at all; that ‘the real’ is an intellectual order, or mind, in which every element, being correlative to every other, at once presupposes and is presupposed by every other; but that this order communicates itself to us piecemeal, in a process of which the first condition on our part is the conception that there is an order, or something related to something else; and that thus the conception of qualified substance, which in its definite articulation is the end of all our knowledge, is yet in another form, that may be called indifferently either abstract or confused, [2] its beginning. This way of escape, however, was not open to Locke, because with him it was the condition of reality in the idea of the body and its qualities that they should be ‘actually present sensations.’ The priority then of body to the relations of extension, distance, &c., as of that in which these relations are found, must, if body and extension are to be more than nominal essences, be a priority of sensations in time. But, on the other hand, the priority of the idea of space to the ideas of its several modes, and of these again to the idea of body, as of the simpler to the more complex, must no less than the other, if the ideas in question are to be real, be one in time. Locke’s contradiction, then, is that of supposing that of two sensations each is actually present, of two impacts on the sensitive tablet each is actually made, before the other.
[1] See above, paragraph 39.