open, and the agent is generally unable afterwards to recall his somnambulistic experiences.

Readings. On the Imagination, cf. St. Thomas, Comm. De Anima, Lib. III. Lect. 4-6; Carpenter, Mental Physiology, c. xii.; Hamilton, Metaph. Lect. xxxiii.; Porter, op. cit. Part. II. cc. v. vi.; Gutberlet, Die Psychologie, pp. 83, seq. The subject of Dreams is treated by Aristotle in a special tract, cf. St. Thomas, Comm. De Somniis. The rude notions on physiology prevalent among the ancients told very seriously on the value of this work, but nevertheless it contains many strikingly acute observations. Carpenter, op. cit. c. xv. is good on the same subject.

THE term Memory, in ordinary language, designates the faculty of retaining, reproducing, and recognizing representations of past experiences. These several features of memory vary in degree of perfection in the same, and in different individuals. Viewed as the capacity for preserving our mental acquisitions this power has been called the Conservative Faculty. It is an essential condition of all knowledge. The simplest act of judgment, as well as the longest chain of reasoning, necessarily implies retention. But acquisition plus conservation is not enough. During the whole of our life the greater portion of our mental possessions lie below the surface of consciousness, and exist only in a condition of potential resuscitation. It is the power of recalling and recognizing these dormant cognitions which completes and perfects this instrument of knowledge. The act of recognition is radically distinct from the mere reapparition of an old mental state; but both have been sometimes comprehended under the Reproductive Faculty. We will devote some con

1 Aristotle (De Memoria et Reminiscentia) distinguishes between memory (uvhun), the passive faculty of retention, and reminiscence

sideration to each of the three elements involved, beginning with that of reproduction.

REPRODUCTION.-A little observation of our minds reveals the fact that thoughts and recollections of past events do not occur completely at random. Our fancy can, it is true, move in a very rapid and seemingly arbitrary manner, whilst widely remote actions and episodes often reappear in imagination in an unexpected and disconnected way. Still, closer attention to the reproduced states will usually disclose faint and unobtrusive connexions. binding together the links of what at first looked like a haphazard series of thoughts.

But it is in the act of reminiscence, in the sustained effort to recall some past experience, we perceive most clearly that the current of representations which pass before our consciousness do not proceed in an entirely casual and lawless manner. Starting from a vague notion of the event which we wish to remember, we try to go back to it by something connected with it in time, in place, or by any other

(avάuvnois), the power of active search or recall. The division is analogous to that of modern writers into spontaneous or automatic memory, and voluntary memory, or the power of recollection. The operation of reminiscence is compared by St. Thomas to that of syllogising, a progress from the known to the unknown, from the remembered to the forgotten. As it involves volitional and rational activity it is restricted to man, whilst memory is common to the brutes. Hamilton confines the name memory to the retentive or conservative capacity of the mind, whilst under the reproductive faculty he includes both reproduction and recognition. The imagination proper, he describes as the representative faculty. Mr. Sully classifies all forms of activity which pertain to our power of remembering as elements of the Reproductive Imagination. This he contrasts with the Productive Imagination, or Imagination proper.

kind of affinity. We notice in the operation that by fixing our attention on any particular occurrence we bring it into greater vividness, and numerous attendant circumstances are gradually recalled. Our ordinary procedure is to seize upon, and intensify [by attention] the force of that one of the newly-awakened recollections which we judge most likely to lead to the desired end. When our gaze is focussed on this fresh centre a new system of related objects begins to emerge from obscurity, and here we repeat our process of choice, picking out again the most promising train. By reiterated selections and rejections of this kind we get gradually closer and closer to the object of pursuit, until it finally flashes upon us with a more or less lively feeling of satisfaction. Throughout our investigation we must have had some vague idea, some general outline of the experience of which we are in search, in order to direct us along the most likely paths. That we necessarily have some dim notion of the forgotten occurrence is made evident in the final act of recognition, for in this stage we become conscious that the rediscovered fact fits precisely into the vague outline still retained. The accompanying pleasure is due to the perception of agreement between the new and the old, together with the feeling of relief occasioned by having the undefined want satisfied.

The study of such an operation as that just described convinces us that our recollections succeed each other not arbitrarily, but according to certain laws. Careful observation of our mental processes

have enabled psychologists to reduce such laws to a few very general principles. These principles which condition the reproduction of phenomena of the mind have been called the Laws of Mental Suggestion or the Laws of the Association of Ideas. The chief of these are: (1) the law of similarity or affinity in character; (2) the law of contrast or opposition in character; and (3) the law of contiguity, comprising association (a) in space, and (b) in time.

The Law of Association by Similarity expresses the general condition that the mind in the presence of any mental state tends to reproduce the like of that state in past experience, or as it is sometimes enunciated, mental states suggest or recall their like in past experience. The previous form of expression, however, possesses the advantage of calling attention to a point frequently overlooked by English psychologists, namely, that it is in the mind, and not in the transient phenomena, the binding or associating force dwells. An impression or idea, viewed merely as an individual phenomenon, contains no reason in itself why

another mental event like or unlike it should be its successor. It is only the permanence of the subject which renders association of the states possible. The mind, retaining as habits or faint modifications former experiences, resuscitates on the occurrence of similar or contrasted events the latent state, and recognizes the likeness which subsists between the new and the old. The vicious reasoning of sensationalist writers who explain both the mind and the material world, including the