241. Such being the only possible object, how can qualities of it be perceived? We cannot here find refuge in any such propensity to feign as that which, according to Hume, leads us to ‘endow objects with a continued existence, distinct from our perceptions.’ If such propensities can give rise to impressions at all, it can only be to impressions of reflection, and it cannot be in virtue of them that extension, an impression of sensation, is given as a quality of an object. Now if there is any meaning in the phrase ‘qualities of an object,’ it implies that the qualities co-exist with each other and the object. Feelings, then, which are felt as qualities of another feeling must co-exist with, i.e. (according to Hume) be felt at the same time as, it and each other. Thus, if an impression of sight be the supposed object, no feeling that occurs after this impression has disappeared can be a quality of it. Accordingly, when Hume speaks of extension being seen as one of the qualities of this table, he is only entitled to mean that it is one among several feelings, experienced at one and the same time, which together constitute the table. Whatever is not so experienced, whether extension or anything else, can be no quality of that ‘perception.’ How much of the perception, then, will survive? Can any feelings, strictly speaking, be cotemporaneous? Those received through different senses, as Hume is careful to show, may be; e.g. the smell, taste, and colour of a fruit. [1] In regard to them, therefore, we may waive the difficulty, How can feelings successive to each other be yet co-existent qualities? but only to find ourselves in another as to what the object may be of which the cotemporaneous feelings are qualities. It cannot, according to Hume, be other than one or all of the cotemporaneous feelings. Is, then, the taste of an apple a quality of its colour or of its smell, or of colour, smell, and taste put together? It will not help us to speak of the several feelings as qualities of the ‘total impression;’ for the ‘total impression’ either merely means the several feelings put together, or else covertly implies just that reference to an object other than these, which Hume expressly excludes.
[1] ‘The taste and smell of any fruit are inseparable from its other qualities of colour and tangibility, and … ’tis certain they are always co-existent. Nor are they only co-existent in general, but also cotemporary in their appearance in the mind.’ p. 521. (Contrast p. 370, where existence and appearance are identified.) [Book I, part IV., sec. V. and part II, sec. IV.]
The thing will have ceased before the quality begins to be.
242. In fact, however, when he speaks of the feeling, which is called extension, as a quality of the feeling, which is called sight, of the table, he has not even the excuse that he might have had if the feelings in question, being of different senses, might be cotemporary. According to him they are feelings of the same sense. The extension of the table he took to be a datum of sight just as properly as its colour; yet he cannot call it the same as colour, but only ‘a quality of the coloured object.’ As the ‘coloured object,’ however, apart from ‘propensities to feign,’ can, according to him, be no other than the feeling of colour, his doctrine can only mean that, colour and extension being feelings of the same sense, the latter is a quality of the former. Is this any more possible than that red should be a quality of blue, or a sour taste of a bitter one? Must not the two feelings be successive, however closely successive, so that the one which is object will have disappeared before the other, which is to be its quality, will have occurred? [1]
[1] It should be needless to point out that by taking extension to be a quality of ‘tangibility’ or muscular effort we merely change the difficulty. The question as to its relation to such feelings will be simply a repetition of that, put in the text, as to its relation to the feeling of colour.
Hume equivocates by putting ‘coloured points’ for colour.
243. If we look to the detailed account which Hume gives of the relation between extension and colour, we find that he avoids the appearance of making one feeling a quality of another, by in fact substituting for colour a superficies of coloured points, in which it is very easy to find extension as a quality because it already is extension as an object. To speak of extension, though a feeling, as made up of parts is just as legitimate or illegitimate as to speak of the feeling of colour being made up of coloured points. The legitimacy of this once admitted, there remains, indeed, a logical question as to how it is that a quality should be spoken of in terms that seem proper to a substance—as is done when it is said to consist of parts—and yet, again, should be pronounced a relation of these parts; but to one who professed to merge all logical distinctions in the indifference of simple feeling, such a question could have no recognised meaning. It is, then, upon the question whether, according to Hume’s doctrine of perception, the perception of an object made up of coloured points may be used interchangeably with the perception of colour, that the consistency of his doctrine of extension must finally be tried.
244. The detailed account is to the following effect:—‘Upon opening my eyes and turning them to the surrounding objects, I perceive many visible bodies; and upon shutting them again and considering the distance betwixt these bodies, I acquire the idea of extension.’ From what impression, Hume proceeds to ask, is this idea derived? ‘Internal impressions’ being excluded, ‘there remain nothing but the senses which can convey to us this original impression.’ … ‘The table before me is alone sufficient by its view to give me the idea of extension. This idea, then, is borrowed from and represents some impression which this moment appears to the senses. But my senses convey to me only the impressions of coloured points, disposed in a certain manner. … We may conclude that the idea of extension is nothing but a copy of these coloured points and of the manner of their appearance.’ [1]
[1] Pp. 340 and 341. [Book I, part II., sec. III.]
Can a ‘disposition of coloured points’ be an impression?