CHAP. the fearch is confined within reasonable limits, inftead of being allowed to wander at random amidst a chaos of particulars. VI. OR, to take an instance ftill more immediately applicable to our purpose suppose that a man of letters were to record, in a common-place book, without any method, all the various ideas and facts which occurred to him in the course of his ftudies; what difficulties would he perpetually experience in applying his acquifitions to use? and how completely and easily might thefe difficulties be obviated by referring the particulars of his information to certain general heads? It is obvious, too, that, by doing fo, he would not only have his knowledge much more completely under his command, but as the particulars claffed together would all have fome connexion, more or lefs, with each other, he would be enabled to trace, with advantage, those mutual relations among his ideas, which it is the object of philofophy to afcertain, A COMMON-PLACE book, conducted without any method, is an exact picture of the memory of a man whofe inquiries are not directed by philofophy. And the advantages of order in treasuring up our ideas in the mind, are perfectly analogous to its effects when they are recorded in writing. NOR is this all. In order to retain our knowledge diftinctly and permanently, it is neceffary that we should frequently recal it to our recollection. But how can this be done without the aid of arrangement? Or fuppofing that it were poffible, how much VI. much time and labour would be necessary for bringing under CHA P. our review, the various particulars of which our information is compofed? In proportion as it is properly fyftematised, this time and labour are abridged. The mind dwells habitually, not on detached facts, but on a comparatively fmall number of general principles; and, by means of these, it can fummon up, as occafions may require, an infinite number of particulars affociated with them; each of which, confidered as a folitary truth, would have been as burdenfome to the memory, as the general principle with which it is connected. I WOULD not wish it to be understood from these observations, that philofophy confifts in claffification alone; and that its only use is to affift the memory. I have often, indeed, heard this afferted in general terms; but it appears to me to be obvious, that although this be one of its most important uses, yet fomething more is neceffary to complete the definition of it. Were the cafe otherwife, it would follow, that all claffifications are equally philofophical, provided they are equally comprehenfive. The very great importance of this fubject will, I hope, be a fufficient apology for me, in taking this opportunity to correct some mistaken opinions which have been formed concerning it. CHA P. SECTION IV. Continuation of the fame Subject.-Aid which the Memory derives from Philofophical Arrangement. IT was before obferved, that the great use of the faculty of Memory, is to enable us to treasure up, for the future regulation of our conduct, the results of our paft experience, and of our past reflexions. But in every cafe in which we judge of the future from the past, we must proceed on the belief, that there is, in the course of events, a certain degree, at least, of uniformity. And, accordingly, this belief is not only justified by experience, but (as Dr. Reid has fhewn, in a very fatisfactory manner) it forms a part of the original conftitution of the human mind. In the general laws of the material world, this uniformity is found to be complete; insomuch that, in the same combinations of circumftances, we expect, with the moft perfect affurance, that the fame refults will take place. In the moral world, the course of events does not appear to be equally regular; but ftill it is regular, to fo great a degree, as to afford us many rules of importance in the conduct of life. A KNOW VI. A KNOWLEDGE of Nature, in fo far as it is abfolutely necef- CHA P. fary for the preservation of our animal existence, is obtruded on us, without any reflexion on our part, from our earliest infancy. It is thus that children learn of themselves to accommodate their conduct to the established laws of the material world. In doing so, they are guided merely by memory, and the inftinctive prin- X ciple of anticipation, which has just been mentioned. IN forming conclufions concerning future events, the philofopher, as well as the infant, can only build with fafety on paft experience; and he, too, as well as the infant, proceeds on an instinctive belief, for which he is unable to account, of the uniformity of the laws of nature. There are, however, two important refpects, which diftinguish the knowledge he poffeffes from that of ordinary men. In the First place, it is far more extensive, in confequence of the affiftance which fcience gives to his natural powers of invention and discovery. Secondly, it is not only more easily retained in the memory, and more conveniently applied to ufe, in confequence of the manner in which his ideas are arranged; but it enables him to afcertain, by a process of reasoning, all thofe truths which may be synthetically deduced from his general principles. The illuftration of these particulars will lead to fome useful remarks; and will at the fame time fhew, that, in difcuffing the fubject of this Section, I have not loft fight of the inquiry which occafioned it. I. 1. It was already remarked, that the natural powers of Memory, together with that inftinctive anticipation of the fu 1 VI. CHAP. ture from the paft, which forms one of the original principles of the mind, are fufficient to enable infants, after a very short experience, to preserve their animal existence. The laws of nature, which it is not fo important for us to know, and which are the objects of philofophical curiofity, are not fo obviously expofed to our view, but are, in general, brought to light by means of experiments which are made for the purpose of difcovery; or, in other words, by artificial combinations of circumstances, which we have no opportunity of feeing conjoined in the course of our ordinary experience. In this manner, it is evident, that many connexions may be afcertained, which would never have occurred fpontaneously to our observation. 2. THERE are, too, fome inftances, particularly in the cafe of the aftronomical phenomena, in which events, that appear to common obfervers to be altogether anomalous, are found, upon a more accurate and continued examination of them, to be fubjected to a regular law. Such, in particular, are those phenomena in the heavens, which we are able to predict by means of cycles. In the cafes formerly described, our knowledge of nature is extended by placing her in new fituations. In these cafes, it is extended by continuing our obfervations beyond the limits of ordinary curiofity. 3. IN the cafe of human affairs, fo long as we confine our attention to particulars, we do not obferve the fame uniformity, as in the phenomena of the material world. When, however, we extend our views to events which depend on a combination of different circumstances, fuch a degree of uniformity appears, as |