unknowableness of Things "in themselves," forms no obstacle to our ascribing attributes or properties to them, provided these are always conceived as relative to us. If a thing produces effects of which our sight, hearing, or touch can take cognisance, it follows, and indeed is but the same statement in other words, that the thing has power to produce those effects. These various powers are its properties, and of such, an indefinite multitude is open to our knowledge. But this knowledge is merely phenomenal. The object is known to us only in one special relation, namely, as that which produces, or is capable of producing, certain impressions on our senses; and all that we really know is these impressions. This negative meaning is all that should be understood by the assertion, that we cannot know the Thing in itself; that we cannot know its inmost nature or essence. The inmost nature or essence of a Thing is apt to be regarded as something unknown, which, if we knew it, would explain and account for all the phenomena which the thing exhibits to us. But this unknown something is a supposition without evidence. We have no ground for supposing that there is anything which if known to us would afford to our intellect this satisfaction; would sum up, as it were, the knowable attributes of the object in a single sentence. Moreover, if there were such a central property, it would not answer to the idea of an 66 inmost nature; " for if knowable by any intelligence, it must, like other properties, be relative to the intelligence which knows it, that is, it must solely consist in producing in that intelligence some specifically definite state of consciousness; for this is the only idea we have of knowing; the only sense in which the verb "to know" means anything.

It would, no doubt, be absurd to assume that our words exhaust the possibilities of Being. There may be innumerable modes of it which are inaccessible to our faculties, and which consequently we are unable to name. But we ought not to speak of these modes of Being by any of the names we possess. These are all inapplicable, because they all stand for known modes of Being. We

might invent new names for such unknown modes; but the new names would have no more meaning than the x, y, z, of Algebra. The only name we can give them which really expresses an attribute, is the word Unknowable.

The doctrine of the Relativity of our knowledge, in the sense which has now been explained, is one of great weight and significance, which impresses a character on the whole mode of philosophical thinking of whoever receives it, and is the key-stone of one of the only two possible systems of Metaphysics and Psychology. But the doctrine is capable of being, and is, understood in at least two other senses. In one of them, instead of a definite and important tenet, it means something quite insignificant, which no one ever did or could call in question. Suppose a philosopher to maintain that certain properties of objects are in the Thing, and not in our senses; in the thing itself, not as whiteness may be said to be in the thing (namely, that there is in the thing a power whereby it produces in us the sensation of white), but in quite another manner; and are known to us not indirectly, as the inferred causes of our sensations, but by direct perception of them in the outward object. Suppose the same philosopher nevertheless to affirm strenuously that all our knowledge is merely phenomenal, and relative to ourselves; that we do not and cannot know anything of outward objects, except relatively to our own faculties. I think our first feeling respecting a thinker who professed both these doctrines, would be to wonder what he could possibly mean by the latter of them. It would seem that he must mean one of two trivialities; either that we can only know what we have the power of knowing, or else that all our knowledge is relative to us inasmuch as it is we that know it.

There is another mode of understanding the doctrine of Relativity, intermediate between these insignificant truisms and the substantial doctrine previously expounded. The position taken may be, that perception of Things as they are in themselves is not entirely denied to us, but is so mixed and confounded with

impressions derived from their action on us, as to give a relative character to the whole aggregate. Our absolute knowledge may be vitiated and disguised by the presence of a relative element. Our faculty (it may be said) of perceiving things as they are in themselves, though real, has its own laws, its own conditions, and necessary mode of operation: our cognitions subsequently depend, not solely on the nature of the things to be known, but also on that of the knowing faculty, as our sight depends not solely upon the object seen, but upon that together with the structure of the eye. If the eye were not achromatic, we should see all visible objects with colours derived from the organ, as well as with those truly emanating from the object. Supposing, therefore, that Things in themselves are the natural and proper object of our knowing faculty, and that this faculty carries to the mind a report of what is in the Thing itself, apart from its effects on us, there would still be a portion of uncertainty in these reports, inasmuch as we could not be sure that the eye of our mind is achromatic, and that the message it brings from the Noumenon does not arrive tinged and falsified, in an unknown degree, through an influence arising from the necessary conditions of the mind's action. We may, in short, be looking at Things in themselves, but through imperfect glasses: what we see may be the very Thing, but the colours and forms which the glass conveys to us may be partly an optical illusion. This is a possible opinion and one who, holding this opinion, should speak of the Relativity of our knowledge, would not use the term wholly without meaning. But he could not, consistently, assert that all our knowledge is relative; since his opinion would be that we have a capacity of Absolute knowledge, but that we are liable to mistake relative knowledge for it.

In which, if in any, of these various meanings, was the doctrine of Relativity held by Sir W. Hamilton? To this question, a more puzzling one than might have been expected, we shall endeavour in the succeeding chapter to find an answer.

CHAPTER III.

THE DOCTRINE OF THE RELATIVITY OF HUMAN KNOWLEDGE, AS HELD BY SIR WILLIAM HAMILTON.

It is hardly possible to affirm more strongly or more explicitly than Sir W. Hamilton has done, that Things in themselves are to us altogether unknowable, and that all we can know of anything is its relation to us, composed of, and limited to, the Phenomena which it exhibits to our organs. Let me cite a passage from one of the Appendices to the "Discussions."*

"Our whole knowledge of kind and of matter is re"lative, conditioned-relatively conditioned. Of things "absolutely or in themselves, be they external, be they "internal, we know nothing, or know them only as in"cognisable; and become aware of their incomprehensible existence, only as this is indirectly and accidentally "revealed to us, through certain qualities related to our "faculties of knowledge, and which qualities, again, we "cannot think as unconditioned, irrelative, existent in "and of themselves. All that we know is therefore “phenomenal,—phenomenal of the unknown . . "Nor is this denied; for it has been commonly confessed, that, as substances, we know not what is "Matter, and are ignorant of what is Mind."

This passage might be matched by many others, equally emphatic, and in appearance equally decisive; several of which I shall have occasion to quote. Yet in the sense which the author's phrases seem to conveyin the only important meaning capable of being attached to them-the doctrine they assert was certainly not held * "Discussions on Philosophy," p. 643.

B

by Sir W. Hamilton. He by no means admits that we know nothing of objects except their existence, and the impressions produced by them upon the human mind. He affirms this in regard to what have been called by metaphysicians the Secondary Qualities of Matter, but denies it of the Primary.

On this point his declarations are very explicit. One of the most elaborate of his Dissertations on Reid is devoted to expounding the distinction. The Dissertation begins thus:*

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"The developed doctrine of Real Presentationism, the "basis of Natural Realism" (the doctrine of the author himself)" asserts the consciousness or immediate perception of certain essential attributes of Matter ob"jectively existing; while it admits that other properties "of body are unknown in themselves, and only inferred "as causes to account for certain subjective affections of "which we are cognisant in ourselves. This discrimina"tion, which to other systems is contingent, superficial, "extraneous, but to Natural Realism necessary, radical, "intrinsic, coincides with what since the time of Locke "has been generally known as the distinction of the 'Qualities of Matter or Body, using these terms as "convertible, into Primary and Secondary."

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Further on, he states, in additional development of so-called Natural Realism, " that we have not merely a "notion, a conception, an imagination, a subjective representation-of Extension, for example-called up or suggested in some incomprehensible manner to the "mind, on occasion of an extended object being pre"sented to the sense; but that in the perception of such "an object we really have, as by nature we believe we "have, an immediate knowledge of that external object "as extended."

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If we are not percipient of any extended reality. we are not percipient of body as existing; for body

*Dissertations appended to Sir W. Hamilton's Edition of Reid's Works, p. 825. + Dissertations, p 842.

Ibid.