181. So far we have only considered Berkeley’s reduction of primary qualities, supposed to be sensible, to sensations as it affects the qualities themselves, rather than as it affects the possibility of universal judgments about them. If, indeed, as we have found, such reduction really amounts to the absolute obliteration of the qualities, no further question can remain as to the possibility of general knowledge concerning them. As Berkeley, however, did not admit the obliteration, the further question did remain for him: and the condition of his plausibly answering it was that he should recognise in the ‘idea,’ as subject of predication, that intelligible qualification by relation which he did not recognise in it simply as ‘idea,’ and which essentially differences it from feeling proper. If any particular ‘tangible extension,’ e.g. a right-angled triangle, is only a feeling, or in Berkeley’s own language, ‘a fleeting perishable passion’ [1] not existing at all, even as an ‘abstract idea,’ except when some one’s tactual organs are being affected in a certain way—what are we to make of such a general truth as that the square on its base is always equal to the squares on its sides? Omitting all difficulties about the convertibility of a figure with a feeling, we find two questions still remain—How such separation can be made of the figure from the other conditions of the tactual experience as that propositions should be possible which concern the figure simply; and how a single case of tactual experience—that in which the mathematician finds a feeling called a right-angled triangle followed by another which he calls equality between the squares, &c.—leads in the absence of any ‘necessary connexion’ to the expectation that the sequence will always be the same. [2] The difficulty becomes the more striking when it is remembered that though the geometrical proposition in question, according to Berkeley, concerns the tangible, the experience which suggests it is merely visual.
[1] ‘Principles of Human Knowledge,’ sec. 89.
[2] See above, paragraph 122.
His theory of universals …
182. Berkeley’s answer to these questions must be gathered from his theory of general names. ‘It is, I know,’ he says, ‘a point much insisted on, that all knowledge and demonstration are about universal notions, to which I fully agree: but then it does not appear to me that those notions are formed by abstraction—universality, so far as I can comprehend, not consisting in the absolute positive nature or conception of anything, but in the relation it bears to the particulars signified or represented by it; by virtue whereof it is that things, names, or notions, being in their own nature particular, are rendered universal. Thus, when I demonstrate any proposition concerning triangles, it is to be supposed that I have in view the universal idea of a triangle; which is not to be understood as if I could frame an idea of a triangle which was neither equilateral nor scalene nor equicrural; but only that the particular triangle I considered, whether of this or that sort it matters not, doth equally stand for and represent all rectilinear triangles whatsoever, and is in that sense universal.’ Thus it is that ‘a man may consider a figure merely as triangular.’ (‘Principles of Human Knowledge,’ Introd. secs. 15 and 16.)
… of value, as implying that universality of ideas lies in relation.
183. In this passage appear the beginnings of a process of thought which, if it had been systematically pursued by Berkeley, might have brought him to understand by the ‘percipi,’ to which he pronounced ‘esse’ equivalent, definitely the ‘intelligi.’ As it stands, the result of the passage merely is that the triangle (for instance) ‘in its own nature,’ because ‘particular,’ is not a possible subject of general predication or reasoning: that it is so only as ‘considered’ under a relation of resemblance to other triangles and by such consideration universalized. ‘In its own nature,’ or as a ‘particular idea,’ the triangle, we must suppose, is so much tangible (or visible, as symbolical of tangible) extension, and therefore according to Berkeley a feeling. But a relation, as he virtually admits, [1] is neither a feeling nor felt. The triangle, then, as considered under relation and thus a possible subject of general propositions, is quite other than the triangle in its own nature. This, of course, is so far merely a virtual repetition of Locke’s embarrassing doctrine that real things are not the things which we speak of, and which are the subject of our sciences; but it is a repetition with two fruitful differences—one, that the thing in its ‘absolute positive nature’ is more explicitly identified with feeling; the other, that the process, by which the thing thought and spoken of is supposed to be derived from the real thing, is no longer one of ‘abstraction,’ but consists in consideration of relation. It is true that with Berkeley the mere feeling has a ‘positive nature’ apart from considered relations, [2] and that the considered relation, by which the feeling is universalised, is only that of resemblance between properties supposed to exist independently of it. The ‘particular triangle,’ reducible to feelings of touch, has its triangularity (we must suppose) simply as a feeling. It is only the resemblance between the triangularity in this and other figures—not the triangularity itself—that is a relation, and, as a relation, not felt but considered; or in Berkeley’s language, something of which we have not properly an ‘idea’ but a ‘notion.’ [3]
[1] See ‘Principles of Human Knowledge,’ sec. 89. (2nd edit.)
[2] See below, paragraph 298.
[3] ‘Principles of Human Knowledge,’ Ibid. This perhaps is the best place for saying that it is not from any want of respect for Dr. Stirling that I habitually use ‘notion’ in the loose popular way which he counts ‘barbarous,’ but because the barbarism is so prevalent that it seems best to submit to it, and to use ‘conception’ as the equivalent of the German ‘Begriff.’