The theory of Hamilton is a modification of that of Kant, intended to obviate these consequences, and to relieve the Kantian doctrine itself from the inconsistency which gave rise to them. So long as the reason is regarded as a separate faculty from the understanding, and things in themselves as ideas of the reason, so long the apparent contradictions, which encumber the attempt to conceive the unconditioned, must be regarded as inherent in the constitution of the reason itself, and as the result of its legitimate exercise on its proper objects. This sceptical conclusion Hamilton endeavoured to avoid by rejecting the distinction between the understanding and the reason as separate faculties, regarding the one as the legitimate and positive, the other as the illegitimate and negative, exercise of one and the same faculty. He thus announces, in opposition to Kant, the fundamental doctrine of the Conditioned, as “the distinction between intelligence within its legitimate sphere of operation, impeccable, and intelligence beyond that sphere, affording (by abuse) the occasions of error.”[AB] Hamilton, like Kant, maintained that all our cognitions are compounded of two elements, one contributed by the object known, and the other by the mind knowing. But the very conception of a relation implies the existence of things to be related; and the knowledge of an object, as in relation to our mind, necessarily implies its existence out of that relation. But as so existing, it is unknown: we believe that it is; we know not what it is. How far it resembles, or how far it does not resemble, the object apprehended by us, we cannot say, for we have no means of comparing the two together.
Discussions, p. 633.
Instead; therefore, of saying with Kant, that reason is subject to an inevitable delusion, by which, it mistakes the regulative principles of its own thoughts for the representations of real things, Hamilton would say that the reason, while compelled to believe in the existence of these real things, is not legitimately entitled to make any positive representation of them as of such or such a nature; and that the contradictions into which it falls when attempting to do so are due to an illegitimate attempt to transcend the proper boundaries of positive thought.
This theory does not, in itself, contain any statement of the mode in which we perceive the material world, whether directly by presentation, or indirectly by representative images; and perhaps it might, without any great violence, be adapted to more than one of the current hypotheses on this point. But that to which it most easily adjusts itself is that maintained by Hamilton himself under the name of Natural Realism. To speak of perception as a relation between mind and matter, naturally implies the presence of both correlatives; though each may be modified by its contact with the other. The acid may act on the alkali, and the alkali on the acid, in forming the neutral salt; but each of the ingredients is as truly present as the other, though each enters into the compound in a modified form. And this is equally the case in perception, even if we suppose various media to intervene between the ultimate object and the perceiving mind,—such, e.g., as the rays of light and the sensitive organism in vision,—so long as these media are material, like the ultimate object itself. Whether the object, properly so called, in vision, be the rays of light in contact with the organ, or the body emitting or reflecting those rays, is indifferent to the present question, so long as a material object of some kind or other is supposed to be perceived, and not merely an inmaterial representation of such an object. To speak of our perceptions as mere modifications of mind produced by an unknown cause, would be like maintaining that the acid is modified by the influence of the alkali without entering into combination with it. Such a view might perhaps be tolerated, in connection with the theory of relativity, by an indulgent interpretation of language, but it is certainly not that which the language of the theory most naturally suggests.
All this Mr. Mill entirely misapprehends. He quotes a passage from Hamilton’s Lectures, in which the above theory of Relativity is clearly stated as the mean between the extremes of Idealism and Materialism, and then proceeds to comment as follows:—
“The proposition, that our cognitions of objects are only in part dependent on the objects themselves, and in part on elements superadded by our organs or our minds, is not identical, nor prima facie absurd. It cannot, however, warrant the assertion that all our knowledge, but only that the part so added, is relative. If our author had gone as far as Kant, and had said that all which constitutes knowledge is put in by the mind itself, he would have really held, in one of its forms, the doctrine of the relativity of our knowledge. But what he does say, far from implying that the whole of our knowledge is relative, distinctly imports that all of it which, is real and authentic is the reverse. If any part of what we fancy that we perceive in the objects themselves, originates in the perceiving organs or in the cognising mind, thus much is purely relative; but since, by supposition, it does not all so originate, the part that does not is as much absolute as if it were not liable to be mixed up with, these delusive subjective impressions.”—(P. 30.)
Mr. Mill, therefore, supposes that wholly relative must mean wholly mental; in other words, that to say that a thing is wholly due to a relation between mind and matter is equivalent to saying that it is wholly due to mind alone. On the contrary, we maintain that Sir W. Hamilton’s language is far more accurate than Mr. Mill’s, and that the above theory can with perfect correctness be described as one of total relativity; and this from two points of view. First, as opposed to the theory of partial relativity generally held by the pre-Kantian philosophers, according to which our sensitive cognitions are relative, our intellectual ones absolute. Secondly, as asserting that the object of perception, though composed of elements partly material, partly mental, yet exhibits both alike in a form modified by their relation to each other. The composition is not a mere mechanical juxtaposition, in which each part, though acting on the other, retains its own characteristics unchanged. It may be rather likened to a chemical fusion, in which both elements are present, but each of them is affected by the composition. The material part, therefore, is not “as much absolute as if it were not liable to be mixed up with subjective impressions.”
But we must hear the continuation of Mr. Mill’s criticism:—
“The admixture of the relative element not only does not take away the absolute character of the remainder, but does not even (if our author is right) prevent us from recognising it. The confusion, according to him, is not inextricable. It is for us to ‘analyse and distinguish what elements’ in an ‘act of knowledge’ are contributed by the object, and what by our organs, or by the mind. We may neglect to do this, and as far as the mind’s share is concerned, we can only do it by the help of philosophy; but it is a task to which, in his opinion, philosophy is equal. By thus stripping off such of the elements in our apparent cognitions of things as are but cognitions of something in us, and consequently relative, we may succeed in uncovering the pure nucleus, the direct intuitions of things in themselves; as we correct the observed positions of the heavenly bodies by allowing for the error due to the refracting influence of the atmospheric medium, an influence which does not alter the facts, but only our perception of them.”