to be an inconsistency between two portions of Hamilton's writings, his theory of the perception of the primary qualities of matter in his notes to Reid, and his doctrine of the relativity of knowledge in his Lectures. This is the chief issue of the book; but if the meaning of the word "phenomenon" which we have attributed to Hamilton be a valid one, his philosophy escapes from this criticism by affirming that the primary qualities of matter, that is, the having extension, figure, etc., though not cognized as the effects of matter on us, are yet modes of existence implying an unknown substance, and are hence phenomenal in Hamilton's meaning of the word.

We think it would have been proper enough to object to Hamilton's description of these qualities as effects, in any other sense than as effects on us, a description which confounds effects with attributes; but instead of discovering this confusion, Mr. Mill supposes that Hamilton meant to represent the primary qualities of matter as effects on us, while he inconsistently ascribed to them an existence independently of us. In the criticism on Hamilton's theory of causation, Mr. Mill does indeed. discover a confusion corresponding to this, but he misinterprets it. In this theory Hamilton confounds cause with substance, in a manner analogous to his confounding effects with qualities; but while Mr. Mill has clearly pointed out the fact of this confusion, he has failed, we think, to discover its significance or its origin in the point of view of Hamilton's philosophy. Just as Hamilton extended the application of the word "phenomenon" beyond its use by the idealists, so did he with as little warning extend the word "cause" to denote, not merely one of the essential elements of an event, but also to mean any existence, whether known or unknown, without which neither a quality nor an event could be manifested. With Hamilton a cause signified more than the necessary antecedent of an event. It meant that which makes an antecedent necessary, and without which qualities neither appear nor change. While he denied that a cause in this sense could in itself be known, he maintained that, as implied in all phenomena, it is known as the unchangeable determinant of all changes, and as persisting through change and under all phenomena. The metaphorical phrases and the illustrations by which Hamilton set forth this view of causation, representing the constancy of cause by the law that an effect is equal to the sum of its causes, and that the sum of real existences in causation remains unchanged, are so far misinterpreted by Mr. Mill that he supposes not merely that Hamilton confounded cause with substance, but also the efficient cause with the material, or the cause of changes with the substance which is changed. On the contrary, Hamilton is far from confounding the existence which determines with that which is determined,

or the invariable attributes of the latter with the immutable substance of the former, or the physical law of the indestructibility of matter with the metaphysical law of immutable causes, as Mr. Mill appears to think.

Perhaps in this case also Mr. Mill has chosen rather to hold his author to what he conceives to be an authentic use of terms, than to try to discover the consistent though metaphysical significations in which Hamilton used them. At any rate, in following the course he did, he has made Hamilton appear sufficiently contradictory and absurd, as if his aim were, as we have intimated, rather to discredit the authority of his author than to ascertain and criticise his real doctrines. Thus Mr. Mill says that,

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According to Sir William Hamilton, when we say that everything must have a cause, we mean that nothing begins to exist, but everything has always existed. I ask any one, either philosopher or common man, whether he does not mean the exact reverse; whether it is not because things do begin to exist, that a cause must be supposed for their existence. The very words in which the axiom of causation is commonly stated, and which our author in the first words of his exposition adopts, are, that everything which begins to exist must have a cause. Is it possible that this axiom can be grounded on the fact that we never suppose anything to begin to exist? Does not he who takes away a beginning of existence take away all causation and all need of a cause? Sir William Hamilton entirely mistakes what it is which causation is called in to explain."

We think, rather, that Mr. Mill has entirely mistaken what it is that Sir William Hamilton calls in for this explanation. His problem was to explain the beginnings, the persistence, and the endings of things as phenomena, or as they are known to us, and in their relations in their orders of necessary sequence. This Sir William Hamilton proposes to explain by the doctrine that things, not as phenomena, but in themselves and in their real existence, do not change; and he grounds this doctrine on his law of the conditioned, the really central and characteristic position of his philosophy. With this law, and not by its own merits, must Hamilton's doctrine of causation stand or fall. The unsoundness of this law, which Mr. Mill has sufficiently exposed, is in postulating judgments concerning what, by their very nature, cannot be the subjects of judgments, namely, things in themselves. But this will appear more clearly in what follows.

Mr. Mill's criticism of Hamilton's law of the conditioned, and of the methods followed by Hamilton and his school, are by far the most effective portions of the work. Kant had taught concerning things in themselves, that their existence in an intelligible world and the possi

bility of an intuition of them as noumena, that is, independently of sensuous perception, could be held only as problematical. Such a possibility of knowledge could neither be asserted nor denied from the conditions of possible experience, and neither proved nor disproved from the data of intuition. Sir William Hamilton, holding substantially the same view of a knowledge of the absolute, but rejecting Kant's analysis of the conditions of experience, and his ideal affirmation of ontological beliefs, attempts by a profounder classification of possible realities to prove, while refuting the positions of the absolutists, that we may legitimately hold for true what we can neither conceive as possible nor know by intuition; for logic itself compels us, he thinks, to assert one of two contradictory propositions, and to deny the other, concerning things in themselves, each of which alone might be merely problematical. Hence he held that there are possibilities, neither proved by the capacities of thought nor by those of intuition, which can yet be held for true. These he called the Unconditioned. Those possibilities which experience and its conditions determine he called the Conditioned. The laws of logic, disclosing the limits of the conditioned, make known, according to Hamilton, the existence of the unconditioned, or that of which the possibility cannot be conceived. But how does logic disclose these limits? By showing that of two contradictories, neither of which is contained within the conditioned or the thinkable, one must be true, and hence that truth transcends the thinkable.

Mr. Mill elsewhere, and on wholly different grounds, also rejects conceivability as a test of possibility, and so far agrees with his author. He was, therefore, concerned only with this point of difference, namely, Hamilton's doctrine that, while truth may transcend the thinkable, belief may transcend it also. This he refutes, by showing that there is no validity in applying the laws of logic except to the thinkable. To the Unconditioned to things in themselves the laws of logic cannot be presumed to be applicable. Of phenomenal existences, it is true, the laws of logic cannot be denied; but the antinomies on which Hamilton's doctrine of the Conditioned is founded are propositions about things in themselves, or else they are propositions which are not really inconceivable. Infinite space or duration, for example, may mean that space or time, as known or conceived by us, is without bounds or determinate magnitude. This is perfectly intelligible, and the contradiction of it is conceived as false. But about space and time in themselves, what does infinity, or limitation, or even magnitude, signify? Instead of being, as Hamilton represents them, inconceivable predicates, they are known predicates affirmed of inconceivable subjects. It is not the predicate infinity which it is impossible to conceive, but, according

to Mr. Mill, it is space in itself, since this cannot be made the subject of any judgment.

It

The extreme inadequacy of our conception of infinite space as a phenomenon is virtually the ground on which Hamilton afirms the inconceivability of infinity as predicated of space in itself. or of any other existence, whether noumenon or phenomenon. This inadequacy amounts to impossibility, according to Hamilton; and he consequently affirms that the conception of infinity is simply the notion of the impossibility of conceiving a magnitude without bounds,—that such a conception is only the negation of conceivability itself as applied to magnitude. But Mr. Mill contends that an infinite magnitude, since it is conceived as one greater than any finite one, implies more than the mere negation of conceivability. It is only partially inconceivable. To say that an infinite magnitude is greater than any other is a positive statement, though we can say or think no more about it. It excludes all we can think definitely and adequately, but it does so in a determinate manner, namely, by affirming that the infinite is greater than the finite. affirms the direction of the exclusion; and this notion of the infinite is true, as far as it goes, of the space and time known to us. In other words, we know that the space and time of our apprehension exceed any measurable or assignable magnitudes. But how do we know this? Simply because we have found no limits,—not because we cannot conceive of any. The impossibility of conceiving a limit to space is, according to Mr. Mill, a psychological consequence of our experiences of spaces, and proves nothing save by representing these experiences, which are the real sources of all our knowledge of space. The affirmation of infinity is then only a denial of limits to the space of our experience; and it cannot, therefore, be made about what is by hypothesis beyond our capacities of experience, or about space in itself. On the other hand, the denial of infinity is an affirmation of limits; and since this is not given in our experience of space, or in its possibilities as determined by capacities acquired through experience, it is not conceivable at all, either of phenomenal space or space in itself. Space in itself cannot, therefore, be conceived as either limited or unlimited, since the subject is inconceivable. And, on the other hand, space either in itself, or in relation to us and our experience of it, cannot be conceived as limited, since this predication is inconceivable. But if both the propositions are about space in itself, the necessity of admitting one and denying the other, or the impossibility of any third inconceivable supposition, rests on no evidence of experience or acquired limitation of thought, such limitations being already transcended in the subjects of the propositions.

Hamilton holds, of course, that the unconditioned, the subject of his antinomies, is inconceivable, but he denies, in common with nearly all philosophers, that the laws of logic are determined or limited by experience; and with these premises, his main argument is irrefragable. But of these premises the absolutists deny the former, and Mr. Mill the latter. Against these extremes, therefore, his argument is inconclusive, but it follows from the premises of Cousin and many other philosophers. But Mr. Mill not only objects to Hamilton's application of the ordinary rules of reasoning to propositions about things in themselves, but he joins, as we have seen, with the rest of Hamilton's critics in opposing his subsidiary arguments, or those for the inconceivability of infinity in general as affirmed of anything. Hamilton attempts, in these arguments, to establish contradiction between inconceivables by an appeal to phenomenal experience itself. He asserts of space, as we know it, that limits and the absence of limits are equally inconceivable, and he therefore attempts a proof of the existence of the unconditioned from the facts and laws of the conditioned itself. The fallacy of this attempt Mr. Mill has sufficiently exposed. Either space, as we know it, has limits or it has no limits. In rejecting, in accordance with experience, the first supposition, we both affirm and conceive the last; but in attempting to realize this fully, we find our faculties inadequate. This inadequacy of conception does not amount, however, to impossibility, unless we attempt to transcend space as we know it, and to conceive of an absolute space, about which nothing whatever is knowable or conceivable. But about this we cannot, then, legitimately appeal to phenomenal experience.

Incidental to his discussion of the law of the Conditioned, the interesting distinction of knowledge and belief, which Mr. Mill does not regard as an important one, is briefly criticised. According to him, knowledge and belief differ only in the degrees of their certainty, or else in the degree of the simplicity and directness of the evidence on which they rest. We fully agree with him in rejecting Hamilton's doctrine, that belief can rest on any other basis than one of knowledge; but we think it important to scrutinize more closely a distinction which has played so conspicuous a part in religious philosophy. While opinion, belief, and knowledge differ from each other in respect to the degrees of speculative certainty with which anything is held for true, yet these degrees are specifically distinguishable from each other in the philosophical uses of the words. There are, indeed, four distinguishable forms of holding for true, namely, opinion, belief, contingent knowledge, and perfect knowledge; though the limits between the second and third are not precisely fixed by usage. Perfect knowledge cannot be quesVOL. CIII. NO. 212.

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