a selection is necessary to enable us to profit by reading; and still more so, to enable us to profit by observation, to which every man is indebted for by far the most valuable part of his knowledge.

When we first enter on any new literary pursuit, we commonly find our efforts of attention painful and unsatisfactory. We have no discrimination in our curiosity, and by grasping at everything, we fail in making those moderate acquisitions which are suited to our limited faculties. As our knowledge extends, we learn to know what particulars are likely to be of use to us, and acquire a habit of directing our examination to these, without distracting the attention with others. It is partly owing to a similar circumstance that most readers complain of a defect of memory, when they first enter on the study of history. They cannot separate important from trifling facts, and find themselves unable to retain anything, from their anxiety to secure the whole.

In order to give a proper direction to our attention in the course of our studies, it is useful, before engaging in particular pursuits, to acquire as familiar an acquaintance as possible with the great outlines of the different branches of science,with the most important conclusions which have hitherto been formed in them, and with the most important desiderata which remain to be supplied. In the case too of those parts of knowledge which are not yet ripe for the formation of philosophical systems, it may be of use to study the various hypothetical theories which have been proposed for connecting together and arranging the phenomena. By such general views alone we can prevent ourselves from being lost amidst a labyrinth of particulars, or can engage in a course of extensive and various reading, with an enlightened and discriminating attention. While they withdraw our notice from barren and insulated facts, they direct it to such as tend to illustrate principles which have either been already established, or which, from having that degree of connexion among themselves, which is necessary to give plausibility to a hypothetical theory, are likely to furnish, in time, the materials of a juster system.

Some of the followers of Lord Bacon have, I think, been led, in their zeal for the method of induction, to censure hypothetical theories with too great a degree of severity. Such theories have certainly been frequently of use, in putting philosophers upon the road of discovery. Indeed, it has probably been in this way, that most discoveries have been made; for although a knowledge of facts must be prior to the formation. of a just theory, yet a hypothetical theory is generally our best guide to the knowledge of useful facts. If a man, without forming to himself any conjecture concerning the unknown laws of nature, were to set himself merely to accumulate facts at random, he might, perhaps, stumble upon some important discovery; but by far the greater part of his labours would be wholly useless. Every philosophical inquirer, before he begins a set of experiments, has some general principle in his view, which he suspects to be a law of nature; and although his conjectures may be often wrong, yet they serve to give his inquiries a particular direction, and to bring under his eye a number of facts which have a certain relation to each other. It has been often remarked, that the attempts to discover the philosopher's stone, and the quadrature of the circle, have led to many useful discoveries in chemistry and mathematics. And they have plainly done so, merely by limiting the field of observation and inquiry, and checking that indiscriminate and desultory attention which is so natural to an indolent mind. A hypothetical theory, however erroneous, may answer a similar purpose. "Prudens interrogatio," says Lord Bacon, "est dimidium scientiæ. Vaga enim experientia et se tantum sequens mera palpatio est, et homines potius stupefacit quam informat." What, indeed, are Newton's queries, but so many hypotheses which are proposed as subjects of examination to philosophers? And did not even the great doctrine of gravitation take its first rise from a fortunate conjecture?

1 "Recte siquidem Plato, Qui ali- quo amplior et certior fuerit anticiquid quærit, id ipsum, quod quærit, patio nostra; eo magis directa et comgenerali quadam notione comprehendit : pendiosa erit investigatio."-De Aug. aliter, qui fieri potest, ut illud, cum Scient. lib. v. cap. 3. fuerit inventum, agnoscat?' Idcirco

VOL. II.

2 D

While, therefore, we maintain, with the followers of Bacon, that no theory is to be admitted as proved, any farther than it is supported by facts, we should, at the same time, acknowledge our obligations to those writers who hazard their conjectures to the world with modesty and diffidence. And it may not be improper to add, that men of a systematizing turn are not now so useless as formerly; for we are already possessed of a great stock of facts; and there is scarcely any theory so bad as not to bring together a number of particulars which have a certain degree of relation or analogy to each other.

The foregoing remarks are applicable to all our various studies, whether they are conducted in the way of reading or of observation. From neither of these two sources of information can we hope to derive much advantage, unless we have some general principles to direct our attention to proper objects.

With respect to observation, some farther cautions may be useful; for in guarding against an indiscriminate accumulation of particulars, it is possible to fall into the opposite extreme, and to acquire a habit of inattention to the phenomena which present themselves to our senses. The former is the error of men of little education; the latter is more common among men of retirement and study.

One of the chief effects of a liberal education, is to enable us to withdraw the attention from the present objects of our perceptions, and to dwell at pleasure on the past, the absent, or the future. But when we are led to carry these efforts to an excess, either from a warm and romantic imagination, or from an anxious and sanguine temper, it is easy to see that the power of observation is likely to be weakened, and habits of inattention to be contracted. The same effect may be produced by too early an indulgence in philosophical pursuits before the mind has been prepared for the study of general truths, by exercising its faculties among particular objects and particular occurrences. In this way, it contracts an aversion to the ex-amination of details, from the pleasure which it has experienced in the contemplation or in the discovery of general principles.

Both of these turns of thought, however, presuppose a certain degree of observation; for the materials of imagination are supplied by the senses, and the general truths which occupy the philosopher, would be wholly unintelligible to him, if he was a total stranger to all experience with respect to the course of nature and of human life. The observations, indeed, which are made by men of a warm imagination, are likely to be inaccurate and fallacious; and those of the speculative philosopher are frequently carried no farther than is necessary to enable him to comprehend the terms which relate to the subjects of his reasoning; but both the one and the other must have looked abroad occasionally at nature and at the world, if not to ascertain facts by actual examination, at least to store their minds with ideas.

The metaphysician, whose attention is directed to the faculties and operations of the mind, is the only man who possesses within himself the materials of his speculations and reasonings. It is accordingly among this class of literary men, that habits of inattention to things external have been carried to the greatest extreme.

It is observed by Dr. Reid, that the power of reflection, (by which he means the power of attending to the subjects of our ⚫ consciousness,*) is the last of our intellectual faculties which unfolds itself, and that in the greater part of mankind it never unfolds itself at all. It is a power, indeed, which being subservient merely to the gratification of metaphysical curiosity, it is not essentially necessary for us to possess in any considerable. degree. The power of observation, on the other hand, which is necessary for the preservation even of our animal existence, discovers itself in infants long before they attain the use of speech; or rather I should have said, as soon as they come into the world; and where nature is allowed free scope, it continues active and vigorous through life.

* But Reid herein varies. Compare I. P. p. 40, (in Col. Works, p. 232, a;) I. P. pp. 60, 61, (C. W. pp. 239, b, 240, a;) I. P. p. 105, (C. W. p. 258, a ;) I. P. p. 324, (C. W. p. 347, ab;) I. P. pp.

It was plainly the inten

516, 517, (C. W. pp. 419, b, 420, ab;) I. P. p. 581, (C. W. p. 443, ab.) This caveat applies also to note 2 at p. 122 supra.-Ed.

tion of nature, that in infancy and youth it should occupy the mind almost exclusively, and that we should acquire all our necessary information before engaging in speculations which are less essential; and accordingly this is the history of the intellectual progress, in by far the greater number of individuals. In consequence of this, the difficulty of metaphysical researches is undoubtedly much increased; for the mind being constantly occupied in the earlier part of life about the properties and laws of matter, acquires habits of inattention to the subjects of consciousness, which are not to be surmounted without a degree of patience and perseverance of which few men are capable; but the inconvenience would evidently have been greatly increased, if the order of nature had in this respect been reversed, and if the curiosity had been excited at as early a period, by the phenomena of the intellectual world, as by those of the material. Of what would have happened on this supposition, we may form a judgment from those men who, in consequence of an excessive indulgence in metaphysical pursuits, have weakened to an unnatural degree their capacity of attending to external objects and occurrences. Few metaphysicians, perhaps, are to be found who are not deficient in the power of observation; for, although a taste for such abstract speculations is far from being common, it is more apt perhaps than any other, when it has once been formed, to take an exclusive hold of the mind, and to shut up the other sources of intellectual improvement. As the metaphysician carries within himself the materials of his reasoning, he is not under a necessity of looking abroad for subjects of speculation or amusement; and, unless he be very careful to guard against the effects of his favourite pursuits, he is in more danger than literary men of any other denomination, to lose all interest about the common and proper objects of human curiosity.*

To prevent any danger from this quarter, I apprehend that the study of the mind should form the last branch of the education of youth; an order which nature herself seems to point out, by what I have already remarked with respect to the *See infra, PART THIRD, chap. i. sect. 2, The Metaphysician.-Ed.