1 until we either succeed,' or give up the pursuit as hopeless.' 1 'The reproducing power of the memory altogether depends upon the nature of the associations by which the new idea is linked on to other ideas which have been previously recorded, and which enter into our habitual current of thought.' 2 We usually also recall most easily what we best understand. The automatic action of the memory is also proved in a most striking manner by the occasional, sudden, and unexpected recollection of things which we have been trying in vain to remember, and have therefore dismissed from conscious mental action; it is automatic and unconscious cerebration' which reproduces them. We often detect ourselves thinking, saying, or doing something unconsciously. In order to recall a forgotten idea, we voluntarily pass in review a number of ideas which we know must be, or are likely to be, related to it, in the hope that one or other of these will suggest it through the bond of association; i.e. we search for it by the aid of ideas with which we are familiar; for instance, if it is the name of an acid, we pass in review in succession all the names of that class of bodies we can think of, and, to make the list as complete as possible, we take the names in alphabetical order, trying with each consonant its combination with each of the vowels, and are thus sometimes enabled to select a few names which sound somewhat like the desired one; and by further similar treatment of these we usually find the one we are in search of. A similar sound is often a powerful means of suggesting a lost word, and we have by the above plan always at hand a ready means of making it. We cannot recollect a forgotten idea at all, nor even know that we have forgotten it, unless we are already conscious › Carpenter's Mental Physiology, pp. 467, 468. 2 Ibid. p. 470. of some idea more or less related to it by association; and the reason why we feel sure that we really possess a latent idea which we cannot at all recollect, is because we always have in such a case a vague residuary perception of the bond of association. In consequence of ideas being connected together in diverging groups, and linked together in chains or series, and of our ability also of recalling them after a lapse of time, if the mind once becomes stored with ideas, and even if the senses are lost, the memory can recall the previously acquired ideas, and thus supply the mind with materials for thought and reflection. 'The order of learning,' says Vives, is from the senses to the imagination, and from this to the intellect,' 'from the simple to the complex, from the singular to the universal.' '1 'That only remains readily in the memory which is conceived according to a natural order. If the memory becomes enfeebled, it is with regard to proper names that this enfeeblement is first apparent.' 2 Gratiolet affirms that 'proper names disappear first, then substantives, which are the proper names of things. Adjectives or qualificatives disappear last, and everything disappears with them, because we cannot have an idea of a thing independently of its qualities. We recall things, and the names of things in the ratio of their necessity.' Dr. Itard observes, that in the loss of memory there is first a forgetfulness of names, then of substantives, then of verbs, and next of adjectives.' 4 General principles are more easily remembered than facts, both because they are less in number, and because they have a larger number of bonds of association in the mind. 1 Winslow, Obscure Diseases of the Brain and Mind, p. 362. 2 Ibid. p. 360. 3 Ibid. p. 361. 4 Ibid. p. 362. ། The action of the memory is not only automatic, but often unconscious. Multitudes of past experiences and impressions continually arise into our mental vision without our experiencing any conscious exertion. The act of associative suggestion of ideas is sometimes attended by consciousness and sometimes not; it is only when the ideational action is sufficiently strong, and we direct our observing powers upon it, that we become conscious of it. There is cogent evidence for believing that, during our waking state, precisely similar trains of mental action occur in our brain when we do not observe them, as when we do; just as many of our muscular actions are both automatic and unobserved by us. All these remarks respecting the memory show the importance of that faculty, and therefore the importance of educating it. It is said that Sir Isaac Newton, at one period of his life, entirely forgot the contents of his celebrated “Principia," in consequence of his neglecting to exercise the memory." It is a fact well attested by experience, that the memory may be seriously injured by pressing upon it too hardly and continuously in early life;' but, a regular exercise short of fatigue is improving to it.' 2 The most valuable way of improving the memory for scientific purposes is by systematic study and experience of science, and especially an orderly classification and arrangement of ideas in accordance with the great principles and relations of nature; an empirical classification or arrangement is much less effectual. There is a limit to the number of ideas which the human mind can contain, and new ideas more readily obliterate the impressions of old ones, unless the latter are associated with many others by a strong bond 1 Winslow, Obscure Diseases of the Brain and Mind, p. 680. NECESSITY OF EDUCATING THE MEMORY. 73 of contiguity, such as that supplied by a general principle. To discipline the memory thoroughly, and especially to acquire a ready and accurate use of our knowledge, the ideas should be recalled from time to time by practice in speaking or writing, for Lord Bacon said, 'Reading makes a full man; writing, an accurate man; and speaking, a ready man.' Ideas revived by the memory, especially during the first half of one's life, may be made, by means of study and repetition, even more vivid and enduring than the original impressions of them. Our oldest thoughts are often the most enduring, partly because the sensorium and cerebrum of young persons are usually more receptive of impressions, and partly because the later formed parts of our physical structure are those which most early degenerate and decay. Memory has also numberless diseases and affections which it is unnecessary for me to describe. CHAPTER VI. ON SCIENTIFIC TERMS. EVERY clear scientific idea is the result of a definite act of mental power, and a precise portion of existing knowledge or belief, and its limits are indicated by its essential marks and characteristics, and not by its coincident or accidental associations. Each object and idea also is distinguished from all other objects and ideas by those characteristic marks only. To distinguish a metal, therefore, we need only to know the characteristic signs of a metal; and to recognise copper, we require to know only the distinguishing marks of that substance. When we distingush, we show a difference. All arts acknowledge that then only we know certainly, when we can define; 6 1 : for definition is that which refines the pure essence of things from the circumstances.'1 Ideas and existences are represented by terms and phrases; and as terms and phrases are representatives of thoughts and things, and are the means which enable us to speak about them, the definitions, descriptions, and explanations of terms form a very necessary part of science; and he who would understand science must learn the meaning of the special terms employed in it. The use of symbols to represent ideas and groups of ideas is a great aid to thought. The symbols of algebra and of number, being a condensed form of language, save us still further the labour of thinking. Symbols enable us to concentrate our attention upon those points alone which they represent, by excluding coincidences which would distract the attention. The meanings of geometrical diagrams are usually more fixed than those of words. Often, by putting our ideas into writing during a research, we perceive them more clearly, and preserve them from loss or change. Clear definition and description also greatly assist research. ‘I may remark, in general, that the only persons who succeed in making great alterations in the language of science are not those who make names arbitrarily and as an exercise of ingenuity, but those who have much new knowledge to communicate; so that the vehicle is commended to general reception by the value of what it contains. It is only eminent discoverers to whom the authority is conceded of introducing a new system of names; just as it is only the highest authority in the State which has the power of putting a new coinage in circulation.' 2 1 Milton. 2 Whewell's Philosophy of the Inductive Sciences, vol. i. p. 81. |