that it would be singular, indeed, if, in the Philosophy of the Human Mind, a science, which but a few years ago was confessedly in its infancy, and which certainly labours under many disadvantages peculiar to itself, a step should, all at once, be made to a single principle comprehending all the particular phenomena which we know.

Supposing such a theory to be completely established, it would still be proper to lead the minds of students to it by gradual steps. One of the most important uses of theory, is to give the memory a permanent hold, and a prompt command, of the particular facts which we were previously acquainted with; and no theory can be completely understood, unless the mind be led to it nearly in the order of investigation.

It is more particularly useful, in conducting the studies of others, to familiarize their minds as completely as possible with those laws of nature for which we have the direct evidence of sense or of consciousness, before directing their inquiries to the more abstruse and refined generalizations of speculative curiosity. In natural philosophy, supposing the theory of Boscovich to be true, it would still be proper, or rather indeed absolutely necessary, to accustom students, in the first stage of their physical education, to dwell on those general physical facts which fall under our actual observation, and about which all the practical arts of life are conversant. In like manner, in the philosophy of mind, there are many general facts for which we have the direct evidence of consciousness. The words, Attention, Conception, Memory, Abstraction, Imagination, Curiosity, Ambition, Compassion, Resentment, express powers and principles of our nature, which every man may study by reflecting on his own internal operations. Words corresponding to these, are to be found in all languages, and may be considered as forming the first attempt towards a philosophical classification of intellectual and moral phenomena. Such a classification, however imperfect and indistinct, we may be assured must have some foundation in nature; and it is at least prudent, for a philosopher to keep it in view as the ground-work of his own arrangement. It not only directs our

attention to those facts in the human constitution, on which every solid theory in this branch of science must be founded; but to the facts which, in all ages, have appeared to the common sense of mankind, to be the most striking and important, and of which it ought to be the great object of theorists, not to supersede, but to facilitate the study.

There is, indeed, good reason for believing that many of the facts which our consciousness would lead us to consider, upon a superficial view, as ultimate facts, are resolvable into other principles still more general. "Long before we are capable of reflection," says Dr. Reid, “the original perceptions and notions of the mind are so mixed, compounded, and decompounded, by habits, associations, and abstractions, that it is extremely difficult for the mind to return upon its own footsteps, and trace back those operations which have employed it since it first began to think and to act." The same author remarks, that "if we could obtain a distinct and full history of all that hath passed in the mind of a child, from the beginning of life and sensation, till it grows up to the use of reason; how its infant faculties began to work, and how they brought forth and ripened all the various notions, opinions, and sentiments which we find in ourselves when we come to be capable of reflection; this would be a treasure of natural history, which would probably give more light into the human faculties, than all the systems of philosophers about them since the beginning of the world." To accomplish an analysis of these complicated phenomena into the simple and original principles of our constitution, is the great object of this branch of philosophy; but in order to succeed, it is necessary to ascertain facts before we begin to reason, and to avoid generalizing, in any instance, till we have completely secured the ground that we have gained. Such a caution, which is necessary in all the sciences, is in a more peculiar manner necessary here, where the very facts from which all our inferences must be drawn, are to be ascertained only by the most patient attention; and where almost all of them are, to a great degree, disguised, partly by the inaccuracies of popular language, and partly by the mistaken theories of philosophers.

[As the order established in the intellectual world seems to be regulated by laws perfectly analogous to those which we trace among the phenomena of the material system; and as in all our philosophical inquiries, (to whatever subject they may relate,) the progress of the mind is liable to be affected by the same tendency to a premature generalization, the following extract from an eminent chemical writer may contribute to illustrate the scope and to confirm the justness of some of the foregoing reflections.

"Within the last fifteen or twenty years, several new metals and new earths have been made known to the world. The names that support these discoveries are respectable, and the experiments decisive. If we do not give our assent to them, no single proposition in chemistry can for a moment stand. But whether all these are really simple substances, or compounds not yet resolved into their elements, is what the authors themselves cannot possibly assert; nor would it in the least diminish the merit of their observations, if future experiments should prove them to have been mistaken as to the simplicity of these substances. This remark should not be confined to late discoveries; it may as justly be applied to those earths and metals with which we have been long acquainted."-" In the dark ages of chemistry, the object was to rival nature; and the substance which the adepts of those days were busied to create, was universally allowed to be simple. In a more enlightened period, we have extended our inquiries, and multiplied the number of the elements. The last task will be to simplify; and, by a closer observation of nature, to learn from what small store of primitive materials all that we behold and wonder at was created."1

This analogy between the history of Chemistry and that of the Philosophy of the Human Mind, which has often struck me in contrasting the views of the alchemists with those of Lavoisier and his followers, has acquired much additional value and importance in my estimation, since I had the pleasure to don as a new Metal, under the title of Palladium, by Richard Chenevix, Esq.]

1

[Inquiries concerning the nature of

a Metallic Substance, lately sold in Lon

peruse a late work of M. Degerando; in which I find that the same analogy has presented itself to that most judicious philosopher, and has been applied by him to the same practical purpose of exposing the false pretensions and premature generalizations of some modern metaphysicians.

"It required nothing less than the united splendour of the discoveries brought to light by the new chemical school, to tear the minds of men from the pursuit of a simple and primary element; a pursuit renewed in every age with an indefatigable perseverance, and always renewed in vain. With what feelings of contempt would the physiologists of former times have looked down on the chemists of the present age, whose limited and circumscribed system admits nearly forty different principles in the composition of bodies! What a subject of ridicule would the new nomenclature have afforded to an alchemist!"

"The Philosophy of Mind has its alchemists also; men whose studies are directed to the pursuit of one single principle, into which the whole science may be resolved, and who flatter themselves with the hope of discovering the grand secret, by which the pure Gold of Truth may be produced at pleasure."

"1

Among these alchemists in the science of mind, the first place is undoubtedly due to Dr. Hartley, who not only attempts to account for all the phenomena of human nature from the single principle of association, combined with the hypothetical assumption of an invisible fluid or ether, producing vibrations in the medullary substance of the brain and nerves; but indulges his imagination in anticipating an era, "when future generations shall put all kinds of evidences and inquiries into mathematical forms; reducing Aristotle's ten Categories, and Bishop Wilkins's forty Summa Genera, to the head of quantity alone, so as to make Mathematics and Logic, Natural History and Civil History, Natural Philosophy and philosophy of all other kinds, coincide omni ex parte." If I had never read an

1 [Degerando, Hist. des Systèmes, tom. ii. pp. 481, 482.]

other sentence of this author, I should have required no further evidence of the unsoundness of his understanding.1]

I have only to add that, although I have retained the phrase of the Association of Ideas in compliance with common language, I am far from being completely satisfied with this mode of expression. I have retained it, chiefly that I might not expose myself to the censure of delivering old doctrines in a new form.

As I have endeavoured to employ it with caution, I hope that it has not often misled me in my reasonings. At the same time, I am more and more convinced of the advantages to be derived from a reformation of the common language in most of the branches of science. How much such a reformation has effected in chemistry is well known; and it is evidently much more necessary in the philosophy of mind, where the prevailing language adds to the common inaccuracies of popular expressions, the peculiar disadvantage of being all suggested by the analogy of matter. Often, in the composition of this work, have I recollected the advice of Bergman to Morveau:2 "In reforming the nomenclature of chemistry, spare no word which is improper. They who understand the subject already, will suffer no inconvenience; and they to whom the subject is new, will comprehend it with the greater facility." But it belongs to such authors alone as have extended the boundaries of science by their own discoveries, to introduce innovations in language with any hopes of success.

1 [The foregoing observations I have formerly introduced in a different work; but they now seem to me to belong more properly to this elementary treatise.See Philos. Essays, p. 12, et seq.]

2 "Le savant professeur d'Upsal, M. Bergman, écrivoit à M. de Morveau dans

les derniers temps de sa vie, Ne faites graces à aucune dénomination impropre. Ceux qui savent déjà entendront toujours; ceux qui ne savent pas encore entendront plutôt."-Méthode de Nomenclat. Chémique, par MM. Morveau, Lavoisier, &c.