Note note 30 — ANALYSIS OF THE PHENOMENA OF THE HUMAN MIND James Mill

30 Some further elucidation seems needful of what is here said, in so summary a manner, respecting ideas which it is not in our power to combine: an inability which it is essential to the analysis of some of the more complex phenomena of mind that we should understand the meaning of. The explanation is indicated, but hardly more than indicated, in the text.

It seems to follow from the universal law of association, that any idea could be associated with any other idea, if the corresponding sensations, or even the ideas themselves, were presented in juxtaposition with sufficient frequency. If, therefore, there are ideas which cannot be associated with each other, it must be because there is something that prevents this juxtaposition. Two conditions hence appear to be required, to render ideas incapable of combination. First, the sensations must be incapable of being had together. If we cannot associate the taste of assafœtida with the taste of sugar, it is implied, that we cannot have the taste of assafœtida along with the taste of sugar. If we could, a sufficient experience would enable us to associate the ideas. Here, therefore, is one necessary condition of the impossibility of associating certain ideas with one another. But this condition, though necessary, is not sufficient. We are but too capable of associating ideas together though the corresponding external facts are really incompatible. In the case of many errors, prejudices, and superstitions, two ideas are so closely and obstinately associated, that the man cannot, at least for the time, help believing that the association represents a real coexistence or sequence between outward facts, though such coexistence or sequence may contradict a positive law of the physical world. There is therefore a further condition required to render two ideas unassociable, and this is, that one of them shall be already associated with some idea which excludes the other. Thus far the analysis is carried in the author’s text. But the question remains, what ideas exclude one another? On careful consideration I can only find one case of such exclusion: when one of the ideas either contains, or raises up by association, the idea of the absence of the other. I am aware of no case of absolute incompatibility of thought or of imagination, except between the presence of something and its absence; between an affirmative and the corresponding negative. If an idea irresistibly raises up the idea of the absence of a certain sensation, it cannot become associated with the idea of that sensation; for it is impossible to combine together in the same mental representation, the presence of a sensation and its absence.

We are not yet, however, at the end of the difficulty; for it may be objected, that the idea of the absence of anything is the idea of a negation, of a nullity; and the idea of nothing must itself be nothing—no idea at all. This objection has imposed upon more than one metaphysician; but the solution of the paradox is very simple. The idea of the presence of a sensation is the idea of the sensation itself along with certain accompanying circumstances: the idea of the absence of the sensation is the idea of the same accompanying circumstances without the sensation. For example: my idea of a body is the idea of a feeling of resistance, accompanying a certain muscular action of my own, say of my hand; my idea of no body, in other words, of empty space, is the idea of the same or a similar muscular action of my own, not attended by any feeling of resistance. Neither of these is an idea of a mere negation; both are positive mental representations: but inasmuch as one of them includes the negation of something positive which is an actual part of the other, they are mutually incompatible: and any idea which is so associated with one of them as to recall it instantly and irresistibly, is incapable of being associated with the other.

The instance cited by the author from Dr. Brown, is a good illustration of the law. We can associate the ideas of a plane and of a convex surface as two surfaces side by side; but we cannot fuse the two mental images into one, and represent to ourselves the very same series of points giving us the sensations we receive from a plane surface and those we receive from a convex surface both at once. That this cannot but be so, is a corollary from the elementary law of association. Not only has no instance ever occurred in our experience of a surface which gave us at the same moment both these sets of sensations; but whenever in our experience a surface originally plane, came to give us the sensations we receive from a convex surface (as for instance when we bend a flat sheet of paper), it, at the very same moment, ceased to be, or to appear, a plane. The commencement of the one set of sensations has always been simultaneous with the cessation of the other set, and this experience, not being affected by any change of circumstances, has the constancy and invariability of a law of nature. It forms a correspondingly strong association; and we become unable to have an idea of either set of sensations, those of planeness or those of convexity, without having the idea of the disappearance of the other set, if they existed previously. I believe it will be found that all the mental incompatibilities, the impossibilities of thought, of which so much is made by a certain class of metaphysicians, can be accounted for in a similar manner.—Ed.