cular
ages and nations; but is the very reverse of an affocia
tion which was once equally prevalent. It is obferved by Dr.
Gregory, in the preface to his edition of Euclid's works, that
the more ancient of the Greek writers looked upon grave
founds as high, and acute ones as low; and that the prefent
mode of expreffion on that fubject, was an innovation intro-
duced at a later period *.

IN the inftances which have now been mentioned, our habit of combining the notions of two things, becomes fo strong, that we find it impoffible to think of the one, without thinking at the fame time of the other. Various other examples of the fame fpecies of combination, although, perhaps, not altogether so striking in degree, might easily fo be collected from the subjects about which our metaphyfical fpeculations are employed. The fenfations, for inftance, which are excited in the mind by external objects, and the perceptions of material qualities which follow these fenfations, are to be distinguished from each other only by long habits of patient reflexion. A clear conception of this diftinction may be regarded as the key to all Dr. Reid's reasonings concerning the process of nature in perception; and, till it has once been rendered familiar to the reader, a great part of his writings muft appear unfatisfactory and obfcure.-In truth, our progress in the philosophy of the human mind depends much more on that severe and difcriminating judgment, which enables us to feparate ideas which nature or habit have intimately combined,

*See Note [Q].

than

V.

PART II.

CHA P. than on acuteness of reasoning or fertility of invention. And hence it is, that metaphysical studies are the best of all preparations for those philofophical pursuits which relate to the conduct of life. In none of thefe do we meet with cafual combinations fo intimate and indiffoluble as thofe which occur in metaphyfics; and he who has been accustomed to fuch difcriminations as this fcience requires, will not eafily be imposed on by that confufion of ideas, which warps the judgments of the multitude in moral, religious, and political inquiries.

FROM the facts which have now been stated, it is easy to conceive the manner in which the affociation of ideas has a tendency to mislead the judgment, in the firft of the three cafes already enumerated. When two subjects of thought are so intimately connected together in the mind, that we find it scarcely poffible to confider them apart; it must require no common efforts of attention, to conduct any procefs of reasoning which relates to either. I formerly took notice of the errors to which we are expofed in confequence of the ambiguity of words; and of the neceffity of frequently checking and correcting our general reasonings by means of particular examples; but in the cases to which I allude at prefent, there is (if I may use the expreffion) an ambiguity of things; fo that even when the mind is occupied about particulars, it finds it difficult to feparate the proper objects of its attention from others with which it has been long accustomed to blend them. The cafes, indeed, in which fuch obftinate and invincible affociations are formed among different fubjects of thought, are not very numerous,

CHAP.
V.

and occur chiefly in our metaphysical researches; but in every mind, cafual combinations, of an inferior degree of ftrength, PART II. have an habitual effect in difturbing the intellectual powers, and are not to be conquered without persevering exertions, of which few men are capable. The obvious effects which this tendency to combination produces on the judgment, in confounding together those ideas which it is the province of the metaphysician to distinguish, sufficiently illustrate the mode of its operation in those numerous inftances, in which its influence, though not fo complete and ftriking, is equally real, and far more dangerous.

II. THE affociation of ideas is a fource of fpeculative error, by misleading us in thofe anticipations of the future from the past, which are the foundation of our conduct in life.

THE great object of philofophy, as I have already remarked more than once, is to ascertain the laws which regulate the fucceffion of events, both in the physical and moral worlds; in order that, when called upon to act in any particular combination of circumstances, we may be enabled to anticipate the probable course of nature from our paft experience, and to regulate our conduct accordingly.

As a knowledge of the established connexions among events, is the foundation of fagacity and of skill, both in the practical arts, and in the conduct of life, nature has not only given to all men a strong difpofition to remark, with attention and curiofity, thofe phenomena which have been obferved to happen.

V.

PART II.

CHAP. nearly at the fame time; but has beautifully adapted to the uniformity of her own operations, the laws of affociation in the human mind. By rendering contiguity in time one of the strongest of our affociating principles, fhe has conjoined together in our thoughts, the fame events which we have found conjoined in our experience, and has thus accommodated (without any effort on our part) the order of our ideas to that scene in which we are deftined to act.

THE degree of experience which is neceffary for the prefervation of our animal existence, is acquired by all men without any particular efforts of ftudy. The laws of nature, which it is moft material for us to know, are expofed to the immediate obfervation of our fenfes; and establish, by means of the principle of affociation, a corresponding order in our thoughts, long before the dawn of reafon and reflexion; or at least long before that period of childhood, to which our recollection afterwards extends.

THIS tendency of the mind to affociate together events which have been prefented to it nearly at the fame time; although, on the whole, it is attended with infinite advantages,

yet, like many other principles of our nature, may occafionally

be a fource of inconvenience, unlefs we avail ourselves of our reafon and of our experience in keeping it under proper regulation. Among the various phenomena which are continually paffing before us, there is a great proportion, whose vicinity in time does not indicate a conftancy of conjunction; and unless we be careful to make the diftinction between these two claffes

of

V.

of connexions, the order of our ideas will be apt to correfpond CHA P. with the one as well as with the other; and our unenlightened PART II. experience of the paft, will fill the mind, in numberless inftances, with vain expectations, or with groundless alarms, concerning the future. This difpofition to confound together accidental and permanent connexions, is one great fource of popular fuperftitions. Hence the regard which is paid to unlucky days; to unlucky colours; and to the influence of the planets; apprehensions which render human life, to many, a continued series of abfurd terrors. Lucretius compares them to those which children feel, from an idea of the existence of spirits in the dark:

"Ac veluti pueri trepidant, atque omnia cœcis
"In tenebris metuunt, fic nos, in luce timemus,
"Interdum nihilo quæ funt metuenda magis."

SUCH Spectres can be difpelled by the light of philosophy only; which, by accuftoming us to trace established connexions, teaches us to despise those which are casual; and, by giving a proper direction to that bias of the mind which is the foundation of superstition, prevents it from leading us aftray.

In the instances which we have now been confidering, events come to be combined together in the mind, merely from the accidental circumftance of their contiguity in time, at the mo ment when we perceived them. Such combinations are confined, in a great meafure, to uncultivated and unenlightened minds; or to those individuals who, from nature or education, have a more than ordinary facility of affociation. But there