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THE prejudice which is commonly entertained against metaphysical speculations, seems to arise chiefly from two causes: First, from an apprehension that the subjects about which they are employed, are placed beyond the reach of the human faculties; and, secondly, from a belief that these subjects have no relation to the business of life.
The frivolous and absurd discussions which abound in the writings of most metaphysical authors, afford but too many arguments in justification of these opinions; and if such discussions were to be admitted as a fair specimen of what the human mind is able to accomplish in this department of science, the contempt, into which it has fallen of late, might with justice be regarded as no inconsiderable evidence of the progress which true philosophy has made in the present age. Among the various subjects of inquiry, however, which, in consequence of the vague
use of language, are comprehended under the general title VOL. I. 1
of Metaphysics, there are some, which are essentially distinguished from the rest, both by the degree of evidence which accompanies their principles, and by the relation which they bear to the useful sciences and arts: and it has unfortunately happened, that these have shared in that general discredit, into which the other branches of metaphysics have justly fallen. To this circumstance is probably to be ascribed the little progress, which has hitherto been made in the Philosophy of THE HUMAN MIND ; a science, so interesting in its nature, and so important in its applications, that it could scarcely have failed, in these inquisitive and enlightened times, to have excited a very general attention, if it had not accidentally been classed, in the public opinion, with the vain and unprofitable disquisitions of the schoolmen. In order to obviate these misapprehensions with respect to the subject of the following work, I have thought it proper, in this preliminary chapter, first, to explain the nature of the truths which I propose to investigate ; and, secondly, to point out some of the more important applications of which they are susceptible. In stating these preliminary observations, I may perhaps appear to some to be minute and tedious; but this fault, I am confident, will be readily pardoned by those, who have studied with care the principles of that science of which I am to treat; and who are anxious to remove the prejudices which have, in a great measure, excluded it from the modern systems of education. In the progress of my work, I flatter myself that I shall not often have occasion to solicit the indulgence of my readers for an unnecessary diffuseness. The notions we annex to the words, matter, and mind, as is well remarked by Dr. Reid,” are merely relative. If I am asked, what I mean by matter? I can only explain myself by saying, it is that which is extended, figured, eoloured, moveable, hard or soft, rough or smooth, hot or cold;—that is, I can define it in no other way, than by enumerating its sensible qualities. It is not matter, or body, which I perceive by my senses; but only extension, figure, colour, and certain other qualities, which the constitution of my nature leads me to refer to something, which is extended, figured, and coloured. The case is precisely similar with respect to Mind. We are not immediately conscious of its existence, but we are conscious of sensation, thought, and volition; operations, which imply the existence of something which feels, thinks, and wills. Every man too is impressed with an irresistible conviction, that all these sensations, thoughts, and volitions, belong to one and the same being; to that being, which he calls himself; a being, which he is led, by the constitution of his nature, to consider as something distinct from his body, and as not liable to be impaired by the loss or mutilation of any of his organs.
* Essays on the Active Powers of Man, p. 8, 9.
From these considerations, it appears, that we have the same evidence for the existence of mind, that we have for the existence of body; nay, if there be any difference between the two cases, that we have stronger evidence for it; inasmuch as the one is suggested to us by the subjects of our own consciousness, and the other merely by the objects of our own perceptions: and in this light, undoubtedly, the fact would appear to every person, were it not, that, from our earliest years, the attention is engrossed with the qualities and laws of matter, an acquaintance with which is absolutely necessary for the preservation of our animal existence. Hence it is, that these phenomena occupy our thoughts more than those of mind: that we are perpetually tempted to explain the latter by the analogy of the former, and even to endeavour to refer them to the same general laws; and that we acquire habits of inatten
* * * , * * * * * *
tion to the subjects of our consciousness, too strong to be
more accurate to say, that its aim is unphilosophical. It
* See Note [A] at the end of the volume.
+ Some Metaphysicians, who appear to admit the truth of the foregoing reasoning, have farther urged, that for anything we can prove to the contrary, it is possible, that the unknown substance which has the qualities of extension, figure, and colour, may be the same with the unknown substance which has the attributes of feeling, thinking and willing. But besides that this is only an hypothesis, which amounts to nothing more than a mere possibility, even if it were true, it would no more be propes to say of mind, that it is material, than to say of body, that it is spiritual.
As all our knowledge of the material world is derived from the information of our senses, natural philosophers have, in modern times, wisely abandoned to metaphysirians all speculations concerning the nature of that substance of which it is composed ; concerning the possibility or impossibility of its being created; concerning the efficient causes of the changes which take place in it; and even concerning the reality of its existence, independent of that of percipient beings: and have confined themselves to the humbler province of observing the phenomena it exhibits, and of ascertaining their general laws. By pursuing this plan steadily, they have, in the course of the two last centuries, formed a body of science, which not only does honour to the human understanding, but has had a most important influence on the practical arts of life. This experimental philosophy no one now is in danger of confounding with the metaphysical speculations already mentioned. Of the importance of these, as a separate branch of study, it is possible that some may think more favourably than others; but they are obviously different in their nature from the investigations of physics; and it is of the utmost consequence to the evidence of this last science, that its principles should not be blended with those of the former.
A similar distinction takes place among the questions which may be stated relative to the human mind.—Whether it be extended or unextended ; whether or not it has any relation to place ; and (if it has) whether it resides in the brain, or be spread over the body, by diffusion ; are questions perfectly analogous to those which metaphysicians have started on the subject of matter. It is unnecessary to inquire, at present, whether or not they admit of answer. It is sufficient for my purpose to remark, that they are as widely and obviously different from the view,