state for its immediate antecedent and proximate cause, though extremely probable, cannot hitherto be said to be proved, in the conclusive manner in which this can be proved of sensations; and even were it certain, yet every one must admit that we are wholly ignorant of the characteristics of these nervous states; we know not, and at present have no means of knowing, in what respect one of them differs from another; and our only mode of studying their successions or co-existences must be by observing the successions and co-ex tion of material mechanism; whether we have organs of thought and of emotion in the same sense in which we have organs of sensation. Many eminent physiologists hold the affirmative. These contend that a thought (for example) is as much the result of nervous agency as a sensation; that some particular state of our nervous system, in particular of that central portion of it called the brain, invariably precedes, and is presupposed by, every state of our consciousness. According to this theory, one state of mind is never really produced by another; all are produced by states of body.istences of the mental states of which When one thought seems to call up another by association, it is not really a thought which recalls a thought; the association did not exist between the two thoughts, but between the two states of the brain or nerves which preceded the thoughts: one of those states recalls the other, each being attended, in its passage, by the particular state of consciousness which is consequent on it. On this theory the uniformities of succession among states of mind would be mere derivative uniformities, resulting from the laws of succession of the bodily states which cause them. There would be no original mental laws, no Laws of Mind in the sense in which I use the term, at all; and mental science would be a mere branch, though the highest and most recondite branch, of the science of Physiology. M. Comte, accordingly, claims the scientific cognisance of moral and intellectual phenomena exclusively for physiologists; and not only denies to Psychology, or Mental Philosophy properly so called, the character of a science, but places it, in the chimerical nature of its objects and pretensions, almost on a par with astrology. But, after all has been said which can be said, it remains incontestable that there exist uniformities of succession among states of mind, and that these can be ascertained by observation and experiment. Further, that every mental state has a nervous they are supposed to be the generators or causes. The successions, therefore, which obtain among mental phenomena do not admit of being deduced from the physiological laws of our nervous organisation; and all real knowledge of them must continue, for a long time at least, if not always, to be sought in the direct study, by observation and experiment, of the mental successions themselves. Since, therefore, the order of our mental phenomena must be studied in those phenomena, and not inferred from the laws of any phenomena more general, there is a distinct and separate Science of Mind. The relations, indeed, of that science to the science of physiology must never be overlooked or undervalued. It must by no means be forgotten that the laws of mind may be derivative laws resulting from laws of animal life, and that their truth therefore may ultimately depend on physical conditions; and the influence of physiological states or physiological changes in altering or counteracting the mental successions is one of the most important departments of psychological study. But, on the other hand, to reject the resource of psychological analysis, and construct the theory of the mind solely on such data as physiology at present affords, seems to me as great an error in principle, and an even more serious one in practice. Imperfect as is the science of mind, cite one another. The second is, that when two impressions have been frequently experienced (or even thought of), either simultaneously or in imme I do not scruple to affirm that it is in a considerably more advanced state than the portion of physiology which corresponds to it; and to discard the former for the latter appears to mediate succession, then whenever one an infringement of the true canons of inductive philosophy, which must produce, and which does produce, erroneous conclusions in some very important departments of the science of human nature. § 3. The subject, then, of Psychology is the uniformities of succession, the laws, whether ultimate or derivative, according to which one mental state succeeds another-is caused by, or at least is caused to follow, another. Of these laws, some are general, others more special. The following are examples of the most general laws. First, Whenever any state of consciousness has once been excited in us, no matter by what cause, an inferior degree of the same state of consciousness, a state of consciousness resembling the former, but inferior in intensity, is capable of being reproduced in us, without the presence of any such cause as excited it at first. Thus, if we have once seen or touched an object, we can afterwards think of the object though it be absent from our sight or from our touch. If we have been joyful or grieved at some event, we can think of or remember our past joy or grief, though no new event of a happy or painful nature has taken place. When a poet has put together a mental picture of an imaginary object, a Castle of Indolence, a Una, or a Hamlet, he can afterwards think of the ideal object he has created without any fresh act of intellectual combination. This law is expressed by saying, in the language of Hume, that every mental impression has its idea. of these impressions, or the idea of it, recurs, it tends to excite the idea of the other. The third law is, that greater intensity in either or both of the impressions is equivalent, in rendering them excitable by one another, to a greater frequency of conjunction. These are the laws of ideas, on which I shall not enlarge in this place, but refer the reader to works professedly psychological, in particular to Mr. James Mill's Analysis of the Phenomena of the Human Mind, where the principal laws of association, along with many of their applications, are copiously exemplified, and with a masterly hand.* In * When this chapter was written, Professor Bain had not yet published even the first part ("The Senses and the Intellect") of his profound Treatise on the Mind. this the laws of association have been more comprehensively stated and more largely exemplified than by any previous writer; and the work, having been completed by the publication of "The Emotions and the Will," may now be referred to as incomparably the most complete analytical exbasis of a legitimate induction, which has position of the mental phenomena, on the yet been produced. More recently still, Mr. Bain has joined with me in appending intended to bring up the analytic science to a new edition of the "Analysis" notes of Mind to its latest improvements. Secondly, These ideas, or secondary mental states, are excited by our impressions, or by other ideas, according to certain laws which are called Laws of Association. Of these laws the first is, that similar ideas tend to ex-chology." Many striking applications of the laws of association to the explanation of complex mental phenomena are also to be found in Mr. Herbert Spencer's "Principles of Psy And it is to be remarked that the | can we discover those elementary case is not always one of Composition ideas of resistance derived from our of Causes: the effect of concurring muscular frame in which it has been causes is not always precisely the conclusively shown that the idea orisum of the effects of those causes ginates. These, therefore, are cases when separate, nor even always an of mental chemistry, in which it is effect of the same kind with them. proper to say that the simple ideas Reverting to the distinction which generate, rather than that they comoccupies so prominent a place in the pose, the complex ones. theory of induction, the laws of the phenomena of mind are sometimes analogous to mechanical, but sometimes also to chemical laws. When many impressions or ideas are operating in the mind together, there sometimes takes place a process of a similar kind to chemical combination. When impressions have been so often experienced in conjunction that each of them calls up readily and instantaneously the ideas of the whole group, those ideas sometimes melt and coalesce into one another, and appear not several ideas, but one, in the same manner as, when the seven prismatic colours are presented to the eye in rapid succession the sensation produced is that of white. But as in this last case it is correct to say that the seven colours when they rapidly follow one another generate white, but not that they actually are white; so it appears to me that the Complex Idea, formed by the blending together of several simpler ones, should, when it really appears simple, (that is, when the separate elements are not consciously distinguishable in it,) be said to result from, or be generated by, the simple ideas, not to consist of them. Our idea of an orange really consists of the simple ideas of a certain colour, a certain form, a certain taste and smell, &c., because we can, by interrogating our consciousness, perceive all these elements in the idea. But we cannot perceive, in so apparently simple a feeling as our perception of the shape of an object by the eye, all that multitude of ideas derived from other senses, without which it is well ascertained that no such visual perception would ever have had existence; nor, in our idea of Extension, With respect to all the other con stituents of the mind, its beliefs, its abstruser conceptions, its sentiments, emotions, and volitions, there are some (among whom are Hartley and the author of the Analysis) who think that the whole of these are generated from simple ideas of sensation by a chemistry similar to that which we have just exemplified. These philosophers have made out a great part of their case, but I am not satisfied that they have established the whole of it. They have shown that there is such a thing as mental chemistry; that the heterogeneous nature of a feeling A, considered in relation to B and C, is no conclusive argument against its being generated from B and C. Having proved this, they proceed to show that where A is found B and C were or may have been present; and why, therefore, they ask, should not A have been generated from B and C? But even if this evidence were carried to the highest degree of completeness which it admits of; if it were shown (which hitherto it has not, in all cases, been) that certain groups of associated ideas not only might have been, but actually were present whenever the more recondite mental feeling was experienced, this would amount only to the Method of Agreement, and could not prove causation until confirmed by the more conclusive evidence of the Method of Difference. If the question be whether Belief is a mere case of close association of ideas, it would be necessary to examine experimentally if it be true that any ideas whatever, provided they are associated with the required degree of closeness, give rise to belief. If the inquiry be into the origin of mental study of the generated phenomoral feelings, the feeling, for ex- menon, than a knowledge of the ample, of moral reprobation, it is properties of oxygen and sulphur necessary to compare all the varieties enables us to deduce those of sulphuric of actions or states of mind which acid without specific observation and are ever morally disapproved, and see experiment. Whatever, therefore, whether in all these cases it can be may be the final issue of the attempt shown, or reasonably surmised, that to account for the origin of our judgthe action or state of mind had be- ments, our desires, or our volitions, come connected by association, in the from simpler mental phenomena, it is disapproving mind, with some parti- not the less imperative to ascertain cular class of hateful or disgusting the sequences of the complex phenoideas; and the method employed is, mena themselves by special study in thus far, that of Agreement. But conformity to the canons of Induction. this is not enough. Supposing this Thus, in respect to Belief, psychoproved, we must try further by the logists will always have to inquire Method of Difference whether this what beliefs we have by direct conparticular kind of hateful or disgust-sciousness, and according to what ing ideas, when it becomes associated laws one belief produces another; with an action previously indifferent, will render that action a subject of moral disapproval. If this question can be answered in the affirmative, it is shown to be a law of the human mind that an association of that particular description is the generating cause of moral reprobation. That all this is the case has been rendered extremely probable, but the experiments have not been tried with the degree of precision necessary for a complete and absolutely conclusive induction.* It is further to be remembered, that even if all which this theory of mental phenomena contends for could be proved, we should not be the more enabled to resolve the laws of the more complex feelings into those of the simpler ones. The generation of one class of mental phenomena from another, whenever it can be made out, is a highly interesting fact in psychological chemistry; but it no more supersedes the necessity of an experi *In the case of the moral sentiments, the place of direct experiment is to a considerable extent supplied by historical experience, and we are able to trace with a tolerable approach to certainty the particular associations by which those sentiments are engendered. This has been attempted, so far as respects the sentiment of justice, in a little work by the present author, entitled Utilitarianism. what are the laws in virtue of which one thing is recognised by the mind, either rightly or erroneously, as evidence of another thing. In regard to Desire, they will have to examine what objects we desire naturally, and by what causes we are made to desire things originally indifferent, or even disagreeable to us; and so forth. It may be remarked, that the general laws of association prevail among these more intricate states of mind, in the, same manner as among the simpler ones. A desire, an emotion, an idea of the higher order of abstraction, even our judgments and volitions when they have become habitual, are called up by association, according to precisely the same laws as our simple ideas. § 4. In the course of these inquiries it will be natural and necessary to examine how far the production of one state of mind by another is influenced by any assignable state of body. The commonest observation shows that different minds are susceptible in very different degrees to the action of the same psychological causes. The idea, for example, of a given desirable object will excite in different minds very different degrees of intensity of desire. The same subject of meditation presented to differ cases, such differences in the kind or ent minds, will excite in them very unequal degrees of intellectual action. These differences of mental susceptibility in different individuals may be, first, original and ultimate facts, or, secondly, they may be consequences of the previous mental history of those individuals, or, thirdly and lastly, they may depend on varieties of physical organisation. That the previous mental history of the individuals must have some share in producing or in modifying the whole of their mental character is an inevitable consequence of the laws of mind; but that differences of bodily structure also cooperate is the opinion of all physi- "The sensations which form the ologists, confirmed by common expe- elements of all knowledge are received rience. It is to be regretted that either simultaneously or successively; hitherto this experience, being accepted when several are received simultain the gross without due analysis, has neously, as the smell, the taste, the been made the groundwork of em- colour, the form, &c., of a fruit, their pirical generalisations most detrimen- association together constitutes our tal to the progress of real knowledge. idea of an object; when received sucIt is certain that the natural differ- cessively, their association makes up ences which really exist in the men- the idea of an event. Anything, then, tal predispositions or susceptibilities of which favours the associations of syndifferent persons, are often not uncon- chronous ideas will tend to produce nected with diversities in their organic a knowledge of objects, a perception constitution. But it does not there- of qualities; while anything which fore follow that these organic differ- favours association in the successive ences must in all cases influence the order will tend to produce a knowmental phenomena directly and im- ledge of events, of the order of occurmediately. They often affect them rences, and of the connection of cause through the medium of their psycho- and effect: in other words, in the logical causes. For example, the idea one case a perceptive mind, with a of some particular pleasure may ex- discriminate feeling of the pleasurcite in different persons, even inde-able and painful properties of things, pendently of habit or education, very a sense of the grand and the beautidifferent strengths of desire, and this may be the effect of their different degrees or kinds of nervous susceptibility; but these organic differences, we must remember, will render the pleasurable sensation itself more intense in one of these persons than in the other; so that the idea of the pleasure will also be an intenser feeling, and will, by the operation of mere mental laws, excite an intenser desire, without its being necessary to suppose that the desire itself is directly influenced by the physical peculiarity. As in this, so in many ful will be the result; in the other, a mind attentive to the movements and phenomena, a ratiocinative and philosophic intellect. Now it is an acknowledged principle that all sensations experienced during the presence of any vivid impression become strongly associated with it and with each other, and does it not follow that the synchronous feelings of a sensitive constitution (i.e. the one which has vivid impressions) will be more intimately blended than in a differently formed mind? If this suggestion has any foundation in |