It is obvious that for Spencer the difference between sensation and image is one of degree merely, every image being a nascent sensation. The fundamental law in accordance with which one impression makes nascent other impressions is the law of association. It may be called the Law of Association by Similarity, but is in fact something quite different from the traditional law of that name. It is a law of assimilation, analogous to the process of biological assimilation, and logically is at variance with the whole doctrine of association as understood by James Mill. In Mill association was the name for the bond of connexion discoverable by an analysis of mental phenomena, but it was not the name for the event or process occasioning the reappearance of phenomena in consciousness; such reappearance was taken for granted as the consequence of this discoverable bond of association and of retentiveness. Bain tried to make the term cover both the cognitional relation and the revival process (cf. his definitions of the Law of Contiguity and the Law of Similarity). In Spencer Assimilation (Association by Similarity) is used definitely for the event which brings about the reappearance in consciousness of past experiences, while relations of likeness and difference between feelings are assumed as primary data. By adhering to association as the ground of the objectivity in knowledge and by trying to derive such validity from the psychological principles of assimilation and differentiation, Spencer makes evident the cleavage between the analytic laws of a theory of knowledge, and the explanatory principles of genetic psychology. He stands as the last representative of the old school. Or shall one say, as the first representative of the new?

In taking notice of the treatment of memory given by Thomas Reid, we broke in upon the line of the Associationist school and came upon a method of studying mental phenomena which set out, not from an analysis of knowledge, but from the conception of mind and its faculties. 'It must be by an

anatomy of the mind, that we can discover its powers and principles.' (An Inquiry into the Human Mind, ch. i, § 1.) 'Could we obtain a distinct and full history of all that had passed in the mind of a child, from the beginning of life and sensation, till it grows up to the use of reason; how its infant faculties began to work, and how they brought forth and ripened all the various notions, opinions, and sentiments, which we find in ourselves when we come to be capable of reflection; this would be a treasure of natural history, which would probably give more light into the human faculties than all the systems of philosophers about them since the beginning of the world.' (ibid., p. 1, § 2.) Here there is recognition of the historical method in psychology. This is the method Locke had set out to follow but failed to pursue, and which Reid himself regards as an unattainable ideal. He contented himself with beginning with what he considers as the simplest of the operations of mind, sensation, and with the simplest form of this; viz., the sensation of smell. The effect of this method on his treatment of memory we have already considered. We will conclude this chapter with an account of two of Reid's successors; one of whom shows the influence of the Association school while the other stands outside it: Dr. Thomas Brown and Sir William Hamilton.

Brown sets out from the conception of consciousness as a stream of mental events, which he classifies into two groups corresponding to James Mill's Sensations and Ideas; viz., those which arise in the presence of external objects and those which arise in consequence of certain preceding affections of the mind'. The latter are subdivided into our intellectual states and our emotions. Of the intellectual states, he says,

'The whole order, as composed of feelings, which arise immediately, in consequence of certain former feelings of the mind, may be technically termed, in reference to these feelings which have induced them, Suggestions.' (Lectures on the Philosophy of Human Mind, 1820, Lecture XXXIII.)

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Important for Brown is the distinction between the capacity of suggestion which occasions the procession of ideas in train and the power of detecting relations between members of the train as alike or different, &c. This finding of relations is a distinct function of mind.

'Without it there could be no continued meditation, but only a hurrying confusion of image after image, in wilder irregularity than in the wildest of our dreams.' (Lectures on the Philosophy of Human Mind, Lecture XL.)

'If we analyse our trains of intellectual thoughts . . . we shall find them to be composed of two very different sets of feelings-one set of which are mere conceptions or images of the past, that rise, image after image, in regular sequence, but simply in succession, without any feeling of relation necessarily involved-while the perception of the relation in the various objects of our thought, forms another set of feelings, of course as various as the relations perceived. . . . There is in short, in the mind a capacity of association; or as,... I would rather term it-the capacity of Simple Suggestion, by which feelings formerly existing, are revived in consequence of the mere existence of other feelings, as there is also a capacity of feeling resemblance, difference, proportion, or relation in general, when two or more external objects, or two or more feelings of the mind itself, are considered by us-which mental capacity, in distinction from the former, I would term the capacity of Relative Suggestion, and of these simple and relative suggestions, the whole intellectual trains of thought are composed. (ibid., Lecture XXXIII.)

Here we have just the distinction which is lacking in Bain and the earlier writers on Association. Brown denies the existence of any mysterious bond between the suggesting and the suggested in simple suggestion. He speaks of the feelings arising spontaneously', or at least without the immediate presence of any known external cause. This implies a capacity in the mind for retaining, in a connected train, moments of consciousness which were immediately in sequence, and further it implies that which Spencer termed assimilation, or as Brown terms it the induction of any

past moment by the present moment'. Habit is an illustration of the mind's capacity for forming trains and retaining sequences. The capacity is nowhere fully discussed by Brown. Presumably it is based on the unity of consciousness. In his criticism of Hartley, Brown definitely rejects a physiological explanation of it. Brown's treatment of memory may be compared with that of James Mill. Memory is a complex, and reference to the past is emphasized as the feature which differentiates memory from simple suggestion.

'The remembrance is not a simple but a complex state of mind; and all which is necessary to reduce a remembrance to a mere conception, is to separate from it a part of the complexity-that part of it which constitutes the notion of a certain relation of antecedence. . . . The particular feeling of any moment before the present, as it rises again in our mind, would be a simple conception, if we did not think of it, either immediately or indirectly, in relation to some other feeling earlier or later. It becomes a remembrance when we combine with it this feeling of relation-the relation which constitutes our notion of time; for time, as far as we are capable of understanding it, or rather of feeling it, is nothing more than the varieties of this felt relation, which, in reference to one of the subjects of the relation, we distinguish by the word before, in reference to the other by the word after. It is a relation, I may remark, which we feel nearly in the same manner as we feel the relation which bodies bear to each other, as co-existing in space.' (ibid., Lecture XLI.)

Brown alone of the writers of this period considers the conditions determining the line of suggestion. Why should x induce y rather than z when both have been together with it in consciousness? Brown formulates these conditions under the title Secondary Laws of Suggestion', and they become important additions to the theory of memory. If once the unity of mind is accepted as the ground for the union of co-existing events (and Brown reduces immediate sequence to co-existence), then the varying degrees of strength in such union and the induction of this rather than that

become a definite problem in psychology. Brown did not furnish a key to that problem; he may not even have formulated the problem to himself; but the mere statement of the conditions or of the facts known concerning lines of suggestion is a great advance in psychological theory. No one point in Brown's psychology shows closer affinity with the subsequent teaching of Herbart than this.1 The conditions enumerated by Brown as determining direction of suggestion are nine in number: the duration of the original feeling, the liveliness of the original feeling, its frequency, its recency, its freedom from other connexions, the bodily or mental temperament of the individual, his varying emotions, his varying bodily conditions, and lastly, his fixed habits.

In the psychology of Sir Willam Hamilton we see the influence of the continental writers, and particularly, so far as his treatment of memory is concerned, the influence of Leibnitz. Hamilton, like Reid, sets out from the consideration of consciousness. Consciousness is the summum genus of which the cognitive faculties, the capacities for pleasure and pain, and the exertive or conative faculties are species. But it is more than a collective name for these several faculties and capacities. It is the condition of their existence: knowing, feeling, desiring are possible only under the condition of being known.

When I know, I must know that I know-when I feel, I must know that I feel-when I desire, I must know that I desire.' (Lectures on Metaphysics and Logic, 1811, Lecture IX, P. 192.) Consciousness is thus, on the one hand, the recognition by the mind or ego of its acts and affections; in other words, the self affirmation that certain modifications are known by me, and that these modifications are mine. But, on the other hand, consciousness is not to be viewed as anything different from these modifications themselves, but is, in fact, the general condition of their existence, or of their existence within the sphere of intelligence. Though the simplest act of

Cf. 'Herbart compared with the English Psychologists', G. F. Stout, Mind, vol. xiv, 1889.