a very remote relation to each other; but which, as they all require nearly the same sort of mental exertion, may, without any impropriety, be classed together in the following disquisition. Of these studies, the first, in point of dignity, as well as utility, is unquestionably that which relates to the faculties and powers of the human mind : to which may be added, as branches of the same science, our logical inquiries concerning the conduct of the understanding, our ethical inquiries concerning the theory of morals, our philological inquiries concerning universal grammar, our critical inquiries concerning the philosophy of rhetoric and of the fine arts. The same word Metaphysics is applied to those abstract speculations which relate to the objects of mathematics and of physics,-to our speculations, for example, with respect to number, proportion, space, duration, the first principles of the algebraical art,—the first principles of the method of fluxions,-the first principles of the calculus of probabilities, the measurement of forces, and of the other quantities which fall under the consideration of the natural philosopher,the history of our ideas of hardness, softness, extension, figure, motion; and of other analogous affections of matter, which, in consequence of our early familiarity with them, are seldom subjected to a scientific examination. Above all, it continues to be applied (and, according to vulgar opinion, with peculiar propriety,) to the scholastic discussions concerning the nature and.essence of the soul, and various other topics, on which experience and observation supply us with no data as a foundation for our reasonings.

In the different acceptations which have been just enumerated, of the word Metaphysics, it appears, at first sight, to convey ideas altogether unconnected. It is not improbable, however, that we may be able, by a little attention, to trace some circumstances common to them all. When a philosophical term is transferred from one thing to another, it seldom happens that the transference is made wholly at random. Some sort of connexion or analogy has been perceived between the two subjects, by a kind of intuition, although it may require much re

flection to enable us to say in what the connexion consists. The study of the metaphorical, and perhaps still more of (what I have elsewhere called) the transitive application of language, may, in this way, often assist us in tracing the relations among the different objects of our knowledge; or, at least, may help us to account for the intellectual process by which men have been led to comprehend, under a common term, things apparently different, and even heterogeneous.

With respect to the inquiries formerly enumerated, they will all be found, upon examination, to agree in this, that they require the same sort of mental exertion for their prosecution, inasmuch as all of them depend, for their chief materials, on that power (called by Mr. Locke Reflection) by which the mind turns its attention inwards upon its own operations, and the subjects of its own consciousness. In researches concerning our intellectual and active powers, the mind directs it attention to the faculties which it exercises, or to the propensities which put these faculties in motion. In all the other inquiries which were mentioned, the materials of our reasoning are drawn chiefly, if not entirely, from our own internal resources. Thus, the knowledge we have of space and duration is not derived from an experimental examination of things external, but. from reflection upon ideas coëval with the first exercise of our senses. ideas are, indeed, at first suggested to the mind by the perceptions of sense; but when we engage in metaphysical inquiries concerning them, all our knowledge is derived from materials within ourselves. In like manner, it is from sense that we derive our ideas of hardness, softness, figure, and motion; but when these ideas have been once formed, the metaphysician is in possession of all the data from which his subsequent conclusions with respect to them are to be deduced: nor could he derive any assistance in such inquiries from a thousand experiments on hard, soft, figured, or moving bodies. Indeed, all the metaphysical knowledge which we

The

* An expression which I have borrowed from the late very ingenious Mr. Payne Knight, author of the Analytical Inquiry into the Principles of Taste.-See Philosophical Essays, p. 218.

ever can acquire about these qualities, amounts only to a knowledge of the manner in which our ideas of them are first introduced into the mind; or, to speak more properly, of the occasions when our thoughts were first led to those subjects. Although, therefore, our metaphysical inquiries concerning hardness, softness, figure, and motion, seem, at first to have for their objects external existences, yet they are carried on entirely by the exercise of reflection on our mental operations. Similar observations are applicable to our metaphysical inquiries concerning number and proportion. In our critical researches concerning the principles of the fine arts, our object is, to arrest those ideas which commonly pass through the mind so rapidly as not to be attended to, in order to detect the causes on which our pleasures depend, an exercise of our faculties very similar to that which we have been now considering. In short, I apprehend that all our metaphysical speculations on these points aim only at a more precise definition of our ideas; or rather at a description of the occasions on which they are formed.

From this account of the nature and object of metaphysical studies, it is evident that those individuals who are habitually occupied with them cannot fail to acquire a more than ordinary capacity of withdrawing their thoughts from things external, and of directing them to the phenomena of Mind. They acquire, also, a disposition to examine the origin of whatsoever combinations they may find established in the fancy, and a superiority to the casual associations which warp common understandings. Hence an accuracy and a subtlety in their distinctions on all subjects, and those peculiarities in their views, which are characteristical of unbiassed and original speculation. But, perhaps, the most valuable fruit they derive from their researches is, that scrupulous precision in the use of language, upon which, more than upon any one circumstance whatever, the logical accuracy of our reasonings, and the justness of our conclusions, essentially depend. Accordingly, it will be found, on a review of the History of the Sciences, that the most important steps which have been made in some of

those apparently the most remote from metaphysical pursuits, (in the science, for example, of Political Economy,) have been made by men trained to the exercise of their intellectual powers, by early habits of abstract meditation.*

These important advantages, however, are not to be purchased by the Metaphysician, without some danger of corresponding inconveniencies. As the materials of his reasoning in his favorite inquiries lie entirely within himself, he has no occasion to look abroad for objects to furnish an exercise to his powers, or to gratify his curiosity; and, unless he is at much pains to counteract this tendency by other studies, will be apt to contract gradually an inattention to what is passing around him, and a want of interest in the observation, not only of physical phenomena, but of the characters and manners of the society around him. When the mere metaphysician, accordingly, is called op to exercise his faculties on other subjects, he cannot easily submit to the task of examining details, or of ascertaining facts; and is apt to seize on a few data as first principles, following them out boldly to their remotest consequences, and afterwards employing his ingenuity to reconcile, by means of false refinements, his theoretical assumptions with the exceptions which seem to contradict them. The stock of his acquired knowledge too, is frequently extremely limited; the phenomena about which his curiosity is habitually occupied furnishing inexhaustible materials to his powers of reasoning and invention, without subjecting him to the fatigue of minute and circumstantial observation, or of a laborious research into the opinions of others. What farther contributes to limit his information, is the insulated nature of his pursuits. Most of the other sciences have such mutual connexions and relations, that the attention we bestow on any one excites our curiosity with respect to the rest; while they all unite in a common tendency to lead the thoughts occasionally to those speculations which the metaphysician considers as his peculiar province. Of his appropriate

* Locke, Hume, Smith, Quesnai, Turgot, Morellet, Genovesi, &c. VOL. III.

24

studies alone, it is a distinguishing characteristic to engross to themselves that attention which they have once deeply engaged, and, by withdrawing the curiosity from the fields of observation, of experiment, and of research, to shut up all the external channels of intellectual improvement.

Metaphysical studies, when their effects are not powerfully controlled by the moral principles and feelings of our nature, have a tendency to encourage a disposition to unlimited scepticism on the most interesting and important subjects of philosophical inquiry. As they show us the accidental origin of many of those associations which we were previously accustomed to consider as inseparable from our constitution, they are apt to suggest doubts with respect to the certainty of opinions for which we have the clearest evidence. The impression produced by such doubts is the greater, as we have not here the same checks on the abuses of our reasoning powers, which serve to guard us against error in the other sciences. In physics, our speculative mistakes are contradicted by facts which strike our senses. In math

ematics, an erroneous supposition leads to its own correction, by the absurdity and inconsistency in which it involves us. But, in metaphysics, the absurdities and inconsistencies to which we are led by almost all the systems hitherto proposed to the world, instead of suggeşting corrections and improvements on these systems, have commonly had the effect of producing scepticism with respect to all of them alike. We have a memorable instance of this in the following candid confession of Mr. Hume. "The intense view of these manifold contradictions and imperfections in human reason has so wrought upon me and heated my brain, that I am ready to reject all belief and reasoning, and can look upon no opinion as more probable or likely than another."*

Metaphysical studies, when carried to an excess, have, moreover, a tendency to repress the enthusiasm of our active pursuits, and to deaden our sensibility to many of the best enjoyments of which our nature is susceptible.

* Treatise of Human Nature, Vol. I. p. 466. First Edition.