in which it stands to the other principles of our constitution, we have advanced as far towards an explanation of it as the nature of the subject permits. The various theories which have attempted to account for it by traces or impressions in the sensorium, are obviously too unphilosophical to deserve a particular refutation.* Such, indeed, is the poverty of language, that we cannot speak on the subject without employing expressions which suggest one theory or another; but it is of importance for us always to recollect, that these expressions are entirely figurative, and afford no explanation of the phenomena to which they refer. It is partly with a view to remind my readers of this consideration, that, finding it impossible to lay aside completely metaphorical or analogical words, I have studied to avoid such an uniformity in the employment of them, as might indicate a preference to one theory rather than another; and by doing so, have perhaps sometimes been led to vary the metaphor oftener and more suddenly, than would be proper in a composition which aimed at any degree of elegance. This caution in the use of the common language concerning memory, it seemed to me the more necessary to attend to, that the general disposition which every person feels at the commencement of his philosophical pursuits, to explain the phenomena of thought by the laws of matter, is, in the case of this particular faculty, encouraged by a variety of peculiar circumstances. The analogy between committing a thing to memory that we wish to remember, and engraving on a tablet a fact that we wish to record, is so striking as to present itself even to the vulgar; nor is it perhaps less natural to indulge the fancy in considering memory as a sort of repository, in which we arrange and preserve for future use the materials of our information. The immediate dependence, too, of this faculty on the state of the body, which

*See Note (S.)

is more remarkable than that of any other faculty whatever, (as appears from the effects produced on it by old age, disease, and intoxication,) is apt to strike those who have not been much conversant with these inquiries, as bestowing some plausibility on the theory which attempts to explain its phenomena on mechanical principles.

I cannot help taking this opportunity of expressing a wish, that medical writers would be at more pains than they have been at hitherto, to ascertain the various effects which are produced on the memory by disease and old age. These effects are widely diversified in different cases. In some it would seem that the memory is impaired in consequence of a diminution of the power of attention; in others, that the power of recollection is disturbed in consequence of a derangement of that part of the constitution on which the association of ideas depends. The decay of memory which is the common effect of age, seems to arise from the former of these causes. It is probable, that, as we advance in years, the capacity of attention is weakened by some physical change in the constitution; but it is also reasonable to think, that it loses its vigour partly from the effect which the decay of our sensibility, and the extinction of our passions have, in diminishing the interest which we feel in the common occurrences of life. That no derangement takes place, in ordinary cases, in that part of the constitution on which the association of ideas depends, appears from the distinct and circumstantial recollection which old men retain of the transactions of their youth.* In some diseases,

✦Swift somewhere expresses his surprise, that old men should remember their anecdotes so distinctly, and should, notwithstanding, have so little memory as to tell the same story twice in the course of the same conversation; and a similar remark is made by Montaigne, in one of his Essays: "Surtout les Vieillards sont dangereux, à qui la souvenance des choses passées demeure, et ont perdu la souvenance de leurs redites.”—Liv. i. chap. ix. (Des Menteurs.)

The fact seems to be, that all their old ideas remain in the mind, connected as formerly by the different associating principles; but that the power of attention to new ideas and new occurrences is impaired.

this part of the constitution is evidently affected. A stroke of the palsy has been known, (while it did not destroy the power of speech,) to render the patient incapable of recollecting the names of the most familiar objects. What is still more remarkable, the name of an object has been known to suggest the idea of it as formerly, although the sight of the object ceased to suggest the name.

In so far as this decay of memory which old age brings along with it is a necessary consequence of a physical change in the constitution, or a necessary consequence of a diminution of sensibility, it is the part of a wise man to submit cheerfully to the lot of his nature. But it is not unreasonable to think, that something may be done by our own efforts, to obviate the inconveniences which commonly result from it. If individuals, who, in the early part of life, have weak memories, are sometimes able to remedy this defect, by a greater attention to arrangement in their transactions, and to classification among their ideas, than is necessary to the bulk of mankind, might it not be possible, in the same way, to ward off, at least to a certain degree, the encroachments which time makes on this faculty? The few old men who continue in the active scenes of life to the last moment, it has been often remarked, complain, in general, much less of a want of recollection, than their cotemporaries. This is undoubtedly owing partly to the effect which the pursuits of business must necessarily haye, in keeping alive the power of attention. probably owing also to new habits of arrangement, which the mind gradually and insensibly forms, from the experience of its growing infirmities. The apparent revival of memory in old men, after a temporary decline, (which is a case that happens not unfrequently,) seems to favour this supposition.

But it is

One old man, I have, myself, had the good fortune to know, who, after a long, an active, and an honourable life,

having begun to feel some of the usual effects of advanced years, has been able to find resources in his own sagacity against most of the inconveniences with which they are commonly attended; and who, by watching his gradual decline with the cool eye of an indifferent observer, and employing his ingenuity to retard its progress, has converted even the infirmities of age into a source of philosophical

amusement.

SECTION II.

Of the Varieties of Memory in different Individuals.

It is generally supposed, that, of all our faculties, Memory is that which nature has bestowed in the most unequal degrees on different individuals; and it is far from being impossible that this opinion may be well founded. If, however, we consider, that there is scarcely any man who has not memory sufficient to learn the use of language, and to learn to recognise, at the first glance, the appearances of an infinite number of familiar objects; besides acquiring such an acquaintance with the laws of nature, and the ordinary course of human affairs, as is necessary for directing his conduct in life; we shall be satisfied that the original disparities among men, in this respect, are by no means so immense as they seem to be at first view; and that much is to be ascribed to different habits of attention, and to a difference of selection among the various objects and events presented to their curiosity.

As the great purpose to which this faculty is subservient, is to enable us to collect, and to retain for the future regulation of our conduct, the results of our past experience; it is evident that the degree of perfection which it attains in the case of different persons, must vary; first, with the facility of making the original acquisition; secondly, with the

permanence of the acquisition; and thirdly, with the quickness or readiness with which the individual is able, on particular occasions, to apply it to use. The qualities, therefore, of a good memory are, in the first place, to be susceptible; secondly, to be retentive; and thirdly, to be ready.

It is but rarely that these three qualities are united in the same person. We often, indeed, meet with a memory which is at once susceptible and ready; but I doubt much, if such memories be commonly very retentive: for, susceptibility and readiness are both connected with a facility of associating ideas, according to their more obvious relations; whereas retentiveness, or tenaciousness of memory, depends principally on what is seldom united with this facility, a disposition to system and to philosophical arrangement. These observations it will be necessary to illustrate more particularly.

I have already remarked, in treating of a different subject, that the bulk of mankind, being but little accustomed to reflect and to generalize, associate their ideas chiefly according to their more obvious relations; those, for example, of resemblance and of analogy; and above all, according to the casual relations arising from contiguity in time and place: whereas, in the mind of a philosopher, ideas are commonly associated according to those relations which are brought to light in consequence of particular efforts of attention; such as the relations of Cause and Effect, or of Premises and Conclusion. This difference in the modes of association of these two classes of men, is the foundation of some very striking diversities between them in respect of intellectual character.

In the first place, in consequence of the nature of the relations which connect ideas together in the mind of the philosopher, it must necessarily happen, that when he has occasion to apply to use his acquired knowledge, time and