revelation; thus the Positive philosopher has a primary presumption in favour of the elements out of which his system is constructed, whilst the sceptical philosopher must be content to argue back to the falsehood of these elements, from the impossibility which the dogmatist may experience in combining them into the harmony of truth. For truth is one, and the end of philosophy is the intuition of unity. He repeated that:-"Philosophy is a systematic evolution of the contents of consciousness by the instrumentality of consciousness; it therefore necessarily supposes in both respects the veracity of consciousness." 13

His theory of attention is stated thus :-" The greater the number of objects to which our consciousness is simultaneously extended, the smaller is the interest with which it is able to consider each, and consequently the less vivid and distinct will be the information it obtains of the several objects. Such being the law, it follows, when our interest in any particular object is excited, and when we wish to obtain all the information concerning it in our power, it behoves us to limit our consideration to that object, to the exclusion of others. This is done by an act of volition or desire, which is called attention. But to view attention as a special act of intelligence, and to distinguish it from consciousness is utterly inapt. Consciousness may be compared to a telescope, attention to the pulling out or in of the tubes in accommodating the focus to the object; and we might with equal justice distinguish in the eye the adjustment of the pupil from the general organ of vision, as in the mind distinguish attention from consciousness as a separate faculty. Not, however, that they are to be accounted the same. Attention is consciousness, and something It is consciousness voluntarily applied, under its law of limitations, to some determinate object; it is consciousness concentrated."

more.

Thus, though attention is not a special and separate faculty of mind, it is an interesting and important subject, and he proceeds to consider it in its various relations, as a general phenomena of consciousness. As to the number of objects which the mind can attend to at once, Stewart supposed that we could only attend to one thing at one and the same instant; but Hamilton supposes that consciousness can simultaneously apprehend six objects. Taking this number of objects as the highest which it can embrace at once, the limitation

13 Discussions, p. 85; Lects., Vol. I., p. 267.

of consciousness to five, four, three, two, or one, will all be acts of attention, differing only in degree. 14

Hamilton rightly holds, that even an act of comparison or discrimination supposes that we are able to comprehend, in the unity of consciousness, the different objects to be discriminated. Instead, therefore, of consciousness not being competent to cognise two things at once, it is only possible under this condition.

He distinguishes three kinds of attention: (1) a mere vital and irresistible act, such as when we open our eyes, we cannot by an act of will avert our mind from all perception of sight; (2) an act determined by desire, which, though involuntary, may be resisted by the will; (3) and an act determined by a deliberate volition. It is the third kind of attention which is really of importance in thinking.

He again refers to the law of limitation in relation to attention, and then says:"But whatever be its relation to the special faculties, attention doubles all their efficiency, and affords them a power of which they would otherwise be destitute. It is, in fact, as we are at present constituted, the primary condition of their activity." Hamilton's whole account of attention is exceedingly interesting and valuable, and especially what he says of it in its higher degree,

"15

14 Vol. I., pp. 231-239, et seq. 15 Vol. I., pp. 246-248, et seq. Hamilton gives a clear and interesting explanation of the difficulties of commencing real intellectual efforts, the obstacles that must be overcome before the power of concentrated attention, of continuous thinking, is acquired.

It may not be quite out of character to state briefly my own experience on the subject of attention, or the acquired power of concentration. I admit that Hamilton's statement of the difficulties of commencing real intellectual efforts is quite true, so far as it goes; yet it appears that in many circumstances, the numerous difficulties which have to be overcome at the initial stages are greater than what he represents them to be. In my own case the initial stage was extremely difficult; the circumstances were unpropitious to the acquisition of the power of concentrating attention, as I was almost constantly in the midst of bustle, and seldom alone. By a prolonged course of persistent efforts, I gradually acquired a complete power of concentrating my mind, by an act of will, upon whatever subject I wished to investigate. This will be understood, when I state that the whole of this history was written, and the proof sheets revised, upon the counter of my own small shop, in the midst of the clattering of a stirring street, and at the same time attending to customers coming in and out. Thus, though often interrupted, I mentally work on, unconscious of noise. The power of attention, of concentration, and of continuous thinking, essentially depends on the strength of the acquired command of the will.

VOL. IV.

8

as a direct act of the will, consummated in the habit of deliberate concentration of thought. His view of this, the highest exercise of mind, is as true as it is lucidly expressed.

Among the general phenomena of consciousness, he discusses the question whether we are always consciously active and begins by averring that there is no pure activity or passivity in creation: that all things in the universe of nature are in a state of continual action and counteraction, being always active and passive at once. "God alone must be thought of as a Being active without any mixture of passivity, as His activity is subject to no limitation. But precisely because it is unlimited, it is for us wholly incomprehensible."

We are never directly conscious of passivity; so far as we are conscious, we are active; but whether there may be a mental activity of which we are unconscious, is another question. He touches upon the phenomena of dreaming, talking during sleep, and somnambulism, with the view of ascertaining whether the mind be at any moment wholly unconscious. He refers, as usual, to the opinions of other philosophers, but also gives his own personal experience, that the mind remains conscious during sleep.16

He also discussed the subject of latent mental modifications. He observes, that the possessions of our mind are not to be measured by its present monetary activities, but by the amount of its acquired habits. Thus one knows a science or a language, not merely when he is making a temporary use of it, but inasmuch as he can apply it when and how he pleases, at the command of his will: and so the greater part of our mental treasures lies always behind the sphere of consciousness, hid in the recesses of the mind; this is the first degree of latency. The second degree of latency exists when the mind contains certain systems of knowledge, or habits of action, which it is wholly unconscious of possessing in its ordinary state, but which are revealed to consciousness in certain extraordinary exaltations of its powers. Such as the abnormal states of madness, febrile delirium, somnambulism, catalepsy, etc., when they may flash out into consciousness, and throw into the shade of unconsciousness those other systems by which they had for long been eclipsed and even extinguished. He insists that the theory of latent modifications enables us to account for some of the most perplexing phenomena of mind.17 Sir William's second volume of lectures commenced with his

16 Vol. I., pp. 310-312, 323-337.

17 Vol. I., pp. 339-352, 366, et seq.

exposition of the phenomena of cognition; and he classified the special faculties of knowledge thus:

Such is Hamilton's distribution of the intellectual powers, which he terms the cognitive faculties. He explains distinctly what he meant by a mental faculty,-it is merely a mode of designating a certain class or group of mental energies. In short, all mental powers are only names determined by various orders of mental phenomena; but as these differ from and resemble each other in various ways, various modes of classification may be adopted, and consequently various faculties, in different views, may be the result. "System is only valuable when it is not arbitrarily devised, but arises naturally out of an observation of the facts, and of the whole facts, themselves. On the other hand, to despise system is to despise philosophy; for the end of philosophy is the detection of unity." 18

1. The presentative faculty on its two sides-perception of external objects, and self-consciousness or reflection, forms the faculty of experience; and it affords us all our contingent knowledge. It enables us to cognise an object, when presented within the sphere of external or internal consciousness; but if our knowledge terminated with this, it would be small indeed. 2. So we have not only a faculty of acquiring knowledge, but also a faculty of retaining it— which is properly called Memory. 3. The reproductive faculty enables us to recall our knowledge out of memory into consciousness; it is the power which regulates the succession of our thoughts, or the laws of mental association. 4. But the general capacity of knowledge renders it requisite that, besides the power of evoking out of unconsciousness one portion of our retained information in preference to another, we have the faculty of representing in consciousness what is

18 Vol. II., pp. 3-5; also footnotes to Reid, pp. 221, 242, 511.

thus evoked; and this is effected by the representative faculty, Imagination. 5. The four preceding faculties, or varied acts of acquisition, conservation, reproduction, and representation, form, as it were, a subsidiary class of faculties, furnishing the materials to a higher faculty, which elaborates these; this is the Elaborative faculty, Comparison, or the faculty of relations; and its chief functions are conception, judgment, reasoning, abstraction, and generalisation. 6. The last of the faculties of cognition he called the Regulative faculty-reason or common sense, under which is included all notions, principles, and laws, not derived from experience, but native to the mind, being at once the laws which govern the mind and afford the conditions of its capacity of knowledge. 19

His treatment of perception is somewhat marred by his rather vehement polemic with Dr. Brown; yet his own doctrine may be disentangled from the discussions with which it is mixed up. He is distinguished both as a historian and critic of the theories of perception; but, leaving the historical points as much as possible out of account, his own theory of perception, and his doctrine of Natural Realism, is as follows:

"The question to be determined is this, Is our perception, or our consciousness of external objects, mediate or immediate?" He gives a general historical account of the views of philosophers touching this subject, discusses and criticises them, with much acuteness and great ability; the objections to natural realism are canvassed; and finally, he takes up the consideration of the general questions of the relation of the senses to the external world, with special reference to the views of Dr. Reid, Stewart, and Dr. Brown. The discussion occupies nearly nine lectures, and the same subject is treated in his Discussions, and in the Supplementary Dissertations to Reid's works. 20

He explains his own doctrine thus: "The only object ever perceived is the object in immediate contact-in immediate relation with the organ. What Reid and philosophers in general call the distant object, is wholly unknown to perception; by reasoning we may connect the object of perception with certain antecedents-certain causes, but these, as the result of inference, cannot be the object of

19 Vol. II., pp. 10-26.

20 I originally intended to present a more detailed account of Hamilton's views concerning the theories of perception, and other points, but want of space has forced me to relinquish this.