and accomplished Professor Ferrier, though by a circuitous path, and expressing himself in a very different phraseology, seems to have arrived at essentially the same point of view. These philosophers maintain the Relativity of our knowledge in the most extreme form in which the doctrine can be understood, since they contend, not merely that all we can possibly know of anything is the manner in which it affects the human faculties, but that there is nothing else to be known; that affections of human or of some other minds are all that we can know to exist. ✓

This, however, is far from being the shape in which the doctrine of the Relativity of our knowledge is usually held. To most of those who hold it, the difference between the Ego and the Non-Ego is not one of language only, nor a formal distinction between two aspects. of the same reality, but denotes two realities, each having a separate existence, and neither dependent on the other. In the phraseology borrowed from the Schoolmen by the German Transcendentalists, they regard the Noumenon as in itself a different thing from the Phenomenon, and equally real; many of them would say, much more real, being the permanent Reality, of which the other is but the passing manifestation. They believe that there is a real universe of "Things in Themselves," and that whenever there is an impression on our senses, there is a "Thing in itself," which is behind the phenomenon, and is the cause of it. But as to what this Thing is "in itself," we, having no organs. except our senses for communicating with it, can only know what our senses tell us; and as they tell us nothing but the impression which the thing makes upon us, we do not know what it is in itself at all. We suppose (at least these philosophers suppose) that it must be something "in itself," but all that we know it to be is merely relative to us, consisting in the power of affecting us in certain ways, or, as it is technically called, of producing Phenomena. External things exist, and have an inmost nature, but their inmost nature is inaccessible to

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to us.

our faculties. We know it not, and can assert nothing of it with a meaning. Of the ultimate Realities, as such, we know the existence, and nothing more. But the impressions which these Realities make on us—the sensations they excite, the similitudes, groupings, and successions of those sensations, or, to sum up all this in a common though improper expression, the representations generated in our minds by the action of the Things themselves-these we may know, and these are all that we can know respecting them. In some future state of existence it is conceivable that we may know more, and more may be known by intelligences superior Yet even this can only be true in the same sense in which a person with the use of his eyes knows more than is known to one born blind, or in which we should know more than we do if we were endowed with two or three additional senses. We should have more sensations; phenomena would exist to us of which we have at present no conception; and we might know better than we now do, many of those which are within our present experience; for if the new impressions were linked with the old, as the old are with one another, by uniformities of succession and co-existence, we should now have new marks indicating to us known phenomena in cases in which we should otherwise have been unaware of them. But all this additional knowledge would be, like that which we now possess, merely phenomenal. We should not, any more than at present, know things as they are in themselves, but merely an increased number of relations between them and us. And in the only meaning which we are able to attach to the term, all knowledge, by however exalted an Intelligence, can only be relative to the knowing Mind. If Things have an inmost nature, apart not only from the impressions which they produce, but from all those which they are fitted to produce, on any sentient being, this inmost nature is unknowable, inscrutable, and inconceivable, not to us merely, but to every other creature. To say that even the Creator could know it, is

to use language which to us has no meaning, because we have no faculties by which to apprehend that there is any such thing for him to know.

It is in this form that the doctrine of the Relativity of Knowledge is held by the greater number of those who profess to hold it, attaching any definite idea to the term. These again are divided into several distinct schools of thinkers, by some of whom the doctrine is held with a modification of considerable importance.

Agreeing in the opinion that what we know of Noumena, or Things in themselves, is but their bare existence, all our other knowledge of Things being but a knowledge of something in ourselves which derives its origin from them; there is a class of thinkers who hold that our mere sensations, and an outward cause which produces them, do not compose the whole of this relative knowledge. The Attributes which we ascribe to outward things, or such at least as are inseparable from them in thought, contain, it is affirmed, other elements, over and above sensations plus an unknowable cause. These additional elements are still only relative, for they are not in the objects themselves, nor have we evidence of anything in the objects that answers to them. They are added by the mind itself, and belong, not to the Things, but to our perceptions and conceptions of them. Such properties as the objects can be conceived divested of, such as sweetness or sourness, hardness or softness, hotness or coldness, whiteness, redness, or blacknessthese, it is sometimes admitted, exist in our sensations only. But the attributes of filling space, and occupying a portion of time, are not properties of our sensations in their crude state, neither, again, are they properties of the objects, nor is there in the objects any prototype of them. They result from the nature and structure of the Mind itself: which is so constituted that it cannot take any impressions from objects except in those particular modes. We see a thing in a place, not because the Noumenon, the Thing in itself, is in any place, but because it is the law of our perceptive faculty that we

must see as in some place, whatever we see at all. Place is not a property of the Thing, but a mode in which the mind is compelled to represent it. Time and Space are only modes of our perceptions, not modes of existence, and higher Intelligences are possibly not bound by them. Things, in themselves, are neither in time nor in space, though we cannot represent them to ourselves except under that twofold condition. Again, when we predicate of a thing that it is one or many, a whole or a part of a whole, a Substance possessing Accidents, or an Accident inhering in a Substance-when we think of it as producing Effects, or as produced by a Cause (I omit other attributes not necessary to be here enumerated), we are ascribing to it properties which do not exist in the Thing itself, but with which it is clothed by the laws of our conceptive faculty-properties not of the Things, but of our mode of conceiving them. We are compelled by our nature to construe things to ourselves under these forms, but they are not forms of the Things. The attributes exist only in relation to us, and as inherent laws of the human faculties; but differ from Succession and Duration in being laws of our intellectual, not our sensitive faculty; technically termed Categories of the Understanding. This is the doctrine of the Relativity of our knowledge as held by Kant, who has been followed in it by many subsequent thinkers, German, English, and French.

By the side of this there is another philosophy, older in date, which, though temporarily eclipsed and often contemptuously treated by it, is, according to present appearances, likely to survive it. Taking the same view with Kant of the unknowableness of Things in themselves, and also agreeing with him that we mentally invest the objects of our perceptions with attributes which do not all point, like whiteness and sweetness, to specific sensations, but are in some cases constructed by the mind's own laws; this philosophy, however, does not think it necessary to ascribe to the mind certain innate forms, in which the objects are (as it were)

moulded into these appearances, but holds that Place, Extension, Substance, Cause, and the rest, are conceptions put together out of ideas of sensation by the known laws of association. This, the doctrine of Hartley, of James Mill, of Professor Bain, and other eminent thinkers, and which is compatible with either the acceptance or the rejection of the Berkeleian theory, is the extreme form of one mode of the doctrine of Relativity, as Kant's is of another. Both schemes accept the doctrine in its widest sense-the entire inaccessibility to our faculties of any other knowledge of Things than that of the impressions which they produce in our mental consciousness.

Between these there are many intermediate systems, according as different thinkers have assigned more or less to the original furniture of the mind on the one hand, or to the associations generated by experience on the other. Brown, for example, regards our notion of Space or Extension as a product of association, while many of our intellectual ideas are regarded by him as ultimate and undecomposable facts. But he accepts, in its full extent, the doctrine of the Relativity of our knowledge, being of opinion that though we are assured of the objective existence of a world external to the mind, our knowledge of that world is absolutely limited to the modes in which we are affected by it. The same doctrine is very impressively taught by one of the acutest metaphysicians of recent times, Mr. Herbert Spencer, who, in his "First Principles," insists with equal force upon the certainty of the existence of Things in Themselves, and upon their absolute and eternal relegation to the region of the Unknowable. This is also, apparently, the doctrine of Auguste Comte: though while maintaining with great emphasis the unknowableness of Noumena by our faculties, his aversion to metaphysics prevented him from giving any definite opinion as to their real existence, which, however, his language always by implication assumes.

It is obvious that what has been said respecting the * See, however, below, a note near the end of chap. ix.