than to follow for it is painful to change any of our habits of arrangement, and to relinquish those systems in which we have been educated, and which have long flattered us with an idea of our own wisdom. Dr. Gregory mentions* it as a striking and distinguishing circumstance in the character of Sydenham, that, although full of hypothetical reasoning, it did not render him the less attentive to observation; and that his hypotheses seem to have sat so loosely about him, that either they did not influence his practice at all, or he could easily abandon them whenever they would not bend to his experience.

SECTION V.

Continuation of the same subject-Effects produced on the Memory by committing to Writing our acquired Knowledge.

HAVING treated at considerable length of the improvement of memory, it may not be improper, before leaving this part of the subject, to consider what effects are likely to be produced on the mind by the practice of committing to writing our acquired knowledge. That such a practice is unfavourable, in some respects, to the faculty of memory, by superseding, to a certain degree, the necessity of its exertions, has been often remarked, and I believe is true; but the advantages with which it is attended in other respects, are so important, as to overbalance greatly this trifling inconvenience.

It is not my intention at present to examine and compare together the different methods which have been proposed of keeping a commonplace book. In this, as in other cases of a similar kind, it may be difficult, perhaps, or impossible, to establish any rules which will apply universally. Individuals must be left to judge for themselves, and to adapt their contrivances to the particular nature of their literary pursuits, and to their own peculiar habits of association and arrangement. The remarks which I am to offer are very general, and are intended merely to illustrate a few of the advantages which the art of Writing affords to the philosopher, for recording, in the course of his progress through life, the results of his speculations, and the fruits of his experience.

The utility of writing, in enabling one generation to transmit its discoveries to another, and in thus giving rise to a gradual progress in the species, has been sufficiently illustrated by many authors. Little attention, however, has been paid to another of its effects, which is no less important; I mean, to the foundation which it lays for a perpetual progress in the intellectual powers of the individual.

It is to experience, and to our own reflections, that we are indebted for by far the most valuable part of our knowledge; and hence it is, that although in youth the imagination may be more vigorous, and the genius more original, than in advanced years; yet, in the case of a man of observation and inquiry, the judgment may be expected, at least as long as his faculties remain in perfection, to become every day sounder and more enlightened. It is, however, only by the constant practice of writing, that the results of our experience, and the progress of our

* Lectures on the Duties and Qualifications of a Physician.

ideas, can be accurately recorded. If they are trusted merely to the memory, they will gradually vanish from it like a dream, or will come in time to be so blended with the suggestions of imagination, that we shall not be able to reason from them with any degree of confidence. What improvements in science might we not flatter ourselves with the hopes of accomplishing, had we only activity and industry to treasure up every plausible hint that occurs to us! Hardly a day passes, when many such do not occur to ourselves, or are suggested by others; and detached, and insulated, as they may appear at present, some of them may perhaps afterwards, at the distance of years, furnish the key-stone of an important system.

But it is not only in this point of view that the philosopher derives advantage from the practice of writing. Without its assistance, he could seldom be able to advance beyond those simple elementary truths which are current in the world, and which form, in the various branches of science, the established creed of the age he lives in. How inconsiderable would have been the progress of mathematicians, in their more abstruse speculations, without the aid of the algebraical notation; and to what sublime discoveries have they been led by this beautiful contrivance, which, by relieving the memory of the effort necessary for recollecting the steps of a long investigation, has enabled them to prosecute an infinite variety of inquiries, to which the unassisted powers of the human mind would have been altogether unequal! In the other sciences, it is true, we have seldom or never occasion to follow out such long chains of consequences as in mathematics; but in these sciences, if the chain of investigation be shorter, it is far more difficult to make the transition from one link to another; and it is only by dwelling long on our ideas, and rendering them perfectly familiar to us, that such transitions can, in most instances, be made with safety. In morals and politics, when we advance a step beyond those elementary truths which are daily presented to us in books or conversation, there is no method of rendering our conclusions familiar to us, but by committing them to writing, and making them frequently the subjects of our meditation. When we have once done so, these conclusions become elementary truths with respect to us; and we may advance from them with confidence to others which are more remote, and which are far beyond the reach of vulgar discovery. By following such a plan, we can hardly fail to have our industry rewarded in due time by some important improvement; and it is only by such a plan that we can reasonably hope to extend considerably the boundaries of human knowledge I do not say that these habits of study are equally favourable to brilliancy of conversation. On the contrary, I believe that those men who possess this accomplishment in the highest degree, are such as do not advance beyond elementary truths; or rather, perhaps, who advance only a single step beyond them; that is, who think a little more deeply than the vulgar, but whose conclusions are not so far removed from common opinions, as to render it necessary for them, when called upon to defend them, to exhaust the patience of their hearers, by stating a long train of intermediate ideas. They who have pushed their inquiries much farther than the common systems of their times, and have rendered familiar to their own minds the intermediate steps by which they have been led to their conclusions, are too apt to conceive other men to be in

the same situation with themselves; and when they mean to instruct, are mortified to find that they are only regarded as paradoxical and visionary. It is but rarely we find a man of very splendid and various conversation to be possessed of a profound judgment, or of great originality of genius.

Nor is it merely to the philosopher, who wishes to distinguish himself by his discoveries, that writing affords an useful instrument of study.-Important assistance may be derived from it by all those who wish to impress on their minds the investigations which occur to them in the course of their reading; for although writing may weaken (as I already acknowledged it does) a memory for detached observations, or for insulated facts, it will be found the only effectual method of fixing in it permanently those acquisitions, which involve long processes of reasoning.

When we are employed in inquiries of our own, the conclusions which we form make a much deeper and more lasting impression on the memory, than any knowledge which we imbibe passively from another.This is undoubtedly owing, in part, to the effect which the ardour of discovery has in rousing the activity of the mind, and in fixing its attention; but I apprehend it is chiefly to be ascribed to this that when we follow out a train of thinking of our own, our ideas are arranged in that order which is most agreeable to our prevailing habits of association. The only method of putting our acquired knowledge on a level, in this respect, with our original speculations, is, after making ourselves acquainted with our author's ideas, to study the subject over again in our own way; to pause, from time to time, in the course of our reading, in order to consider what we have gained; to recollect what the propositions are, which the author wishes to establish, and to examine the different proofs which he employs to support them. In making such an experiment, we commonly find, that the different steps of the process arrange themselves in our minds, in a manner different from that in which the author has stated them; and that, while his argument seems, in some places, obscure, from its conciseness, it is tedious in others, from being unnecessarily expanded. When we have reduced the reasoning to that form, which appears to ourselves to be the most natural and satisfactory, we may conclude with certainty, not that this form is better in itself than another, but that it is the best adapted to our memory.— Such reasonings, therefore, as we have occasion frequently to apply, either in the business of life, or in the course of our studies, it is of importance to us to commit to writing, in a language and in an order of our own; and if, at any time, we find it necessary to refresh our recollection on the subject, to have recourse to our own composition, in preference to that of any other author.

That the plan of reading which is commonly followed is very different from that which I have been recommending, will not be disputed.— Most people read merely to pass an idle hour, or to please themselves with the idea of employment, while their indolence prevents them from any active exertion; and a considerable number with a view to the display which they are afterwards to make of their literary acquisitions. From which so ever of these motives a person is led to the perusal of books, it is hardly possible that he can derive from them any material advantage. If he reads merely from indolence, the ideas which pass through his mind will probably leave little or no impression; and if he

reads from vanity, he will be more anxious to select striking particulars in the matter or expression, than to seize the spirit and scope of the author's reasoning, or to examine how far he has made any additions to the stock of useful and solid knowledge. "Though it is scarce possi"ble," says Dr. Butler,*" to avoid judging, in some way or other, of "almost every thing which offers itself to one's thoughts, yet it is cer"tain, that many persons, from different causes, never exercise their << judgment upon what comes before them, in such a manner as to be "able to determine how far it be conclusive. They are perhaps enter"tained with some things, not so with others; they like, and they dis"like; but whether that which is proposed to be made out, be really "made out or not, whether a matter be stated according to the real "truth of the case, seems to the generality of people, a circumstance "of little or no importance. Arguments are often wanted for somne ac"cidental purpose; but proof, as such, is what they never want, for their "own satisfaction of mind, or conduct in life. Not to mention the multi"tudes who read merely for the sake of taiking, or to qualify themselves "for the world or some such kind of reasons; there are even of the few "who read for their own entertainment, and have a real curiosity to see "what is said, several, which is astonishing, who have no sort of cu"riosity to see what is true: I say curiosity, because it is too obvious "to be mentioned how much that religious and sacred attention which "is due to truth, and to the important question, what is the rule of life, "is lost out of the world.

"For the sake of this whole class of readers, for they are of different "capacities, different kinds, and get into this way from different occa"sions, I have often wished that it had been the custom to lay before "people nothing in matters of argument but premises, and leave them "to draw conclusions themselves; which, although it could not be done "in all cases, might in many.

"The great number of books and papers of amusement, which, of "one kind or another, daily come in one's way, have in part occasion"ed, and most perfectly fall in with and humour this idle way of read"ing and considering things. By this means, time, even in solitude, is "happily got rid of without the pain of attention; neither is any part "of it more put to the account of idleness, one can scarce forbear say"ing, is spent with less thought, than great part of that which is spent "in reading."

If the plan of study which I formerly described were adopted, it would undoubtedly diminish very much the number of books which it would be possible to turn over; but I am convinced that it would add greatly to the stock of useful and solid knowledge; and by rendering our acquired ideas in some measure our own, would give us a more ready and practical command of them: not to mention, that i we are possessed of any inventive powers, such exercises would continually furnish them with an opportunity of displaying themselves upon all the different subjects which may pass under our review.

Nothing, in truth, has such a tendency to weaken, not only the powers of invention, but the intellectual powers in general, as a habit of extensive and various reading, without reflection. The activity and force

* See the preface to his Sermons.

of the mind are gradually impaired, in consequence of disuse; and not unfrequently all our principles and opinions come to be lost in the infinite multiplicity and discordancy of our acquired ideas.

By confining our ambition to pursue the truth with modesty and candour, and learning to value our acquisitions only as far as they contribute to inake us wiser and happier, we may perhaps be obliged to sacrifice the temporary admiration of the common dispensers of literary fame; but we may rest assured, that it is in this way only we can hope to make real progress in knowledge, or to enrich the world with useful inventions.

"It requires courage, indeed," (as Helvetius has remarked,)" to re"main ignorant of those useless subjects which are generally valued ;" but it is a courage necessary to men who either love the truth, or who aspire to establish a permanent reputation.

SECTION VI.

Continuation of the same Subject.-Of Artificial Memory.

By an Artificial Memory is meant, a method of connecting in the mind, things difficult to be remembered, with things easily remembered; so as to enable it to retain, and to recollect the former, by means of the latter. For this purpose, various contrivances have been proposed, but I think the foregoing definition applies to all of them.

Some sorts of artificial memory are intended to assist the natural powers of the human mind on particular occasions which require a more than ordinary effort of recollection; for example, to assist a pub. lic speaker to recollect the arrangement of a long discourse.

Others have been devised with a view to enable us to extend the circle of our acquired knowledge, and to give us a more ready command of all the various particulars of our information.

The topical Memory, so much celebrated among the ancient rhetoricians, comes under the former description.

I already remarked the effect of sensible objects, in recalling to the mind the ideas with which it happened to be occupied, at the time when these objects were formerly perceived. In trayelling along a road, the sight of the more remarkable scenes we meet with, frequently puts us in mind of the subjects we were thinking or talking of when we last saw them. Such facts, which are perfectly familiar even to the vulgar, might very naturally suggest the possibility of assisting the memory, by establishing a connexion between the ideas we wish to remember, and certain sensible objects, which have been found from experience to make a permanent impression on the mind.* I have been told of a young woman, in a very low rank in life, who contrived a method of committing to memory the sermons which she was accustomed to hear, by fixing her attention, during the different heads of the discourse, on different compartments of the roof of the church; in such a manner, as

* "Cum in loca aliqua post tempus reversi sumus, non ipsa agnoscimus tantum, sed etiam, quae in his fecerimus, reminiscimur, personaeque subeunt, nonnunquam tacitae quoque cogitationes in mentem revertuntur. Nata est igitur, ut in plerisque, ars ab experimento.-QUINCT. Inst. Orat. lib. xi. cap. 2.