1 Introduction. man 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 inconfiderable evidence of the progrefs, which true philofophy has made in the prefent age. Among the various fubjects of inquiry, however, which, in confequence of the vague ufe of language, are comprehended under the general title of Metaphyfics, there are fome, which are essentially distinguished from the reft, both by the degree of evidence which accompanies their principles, and by the relation which they bear to the useful fciences and arts: and it has unfortunately happened, that these have shared in that general difcredit, into which the other branches of metaphyfics have juftly fallen. To this actione of the general circumftance is probably to be afcribed, the little progress which - tions of substance has hitherto been made in the PHILOSOPHY OF THE HUMAN Schisan MIND; a science, so interesting in its nature, and so important in its applications, that it could fcarcely have failed, in these inquifitive and enlightened times, to have excited a very general once of the principles attention, if it had not accidentally been claffed, in the public ses of all things opinion, with the vain and unprofitable disquisitions of the ling fchool-men. In order to obviate these misapprehenfions with respect to the fubject of the following work, I have thought it proper, in this preliminary chapter, firft, to explain, the Nature of the truths which I propose to investigate; and, fecondly, to point out some of the more important Applications of which they are susceptible. In ftating these preliminary obfervations, I may perhaps appear to fome to be minute and tedious; but this fault, I am confident, will be readily pardoned by thofe, who have studied with care care the principles of that fcience of which I am to treat; and Introduction. who are anxious to remove the prejudices which have, in a great measure, excluded it from the modern fyftems of education. In the progress of my work, I flatter myself that I shall not often have occafion to folicit the indulgence of my readers, for an unneceffary diffufenefs. 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, coloured, moveable, hard or soft, rough or smooth, hot or cold;—that is, I can define it in no other way, than by enumerating its fenfible qualities. It is not matter, or body, which I perceive by my senses; but only extenfion, 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 cafe is precisely fimilar with respect to Mind. We are not immediately confcious of its existence, but we are confcious of fenfation, thought, and volition; operations, which imply the existence of fomething which feels, thinks, and wills. Every man too is impreffed with an irresistible conviction, that all these fenfations, thoughts, and volitions, belong to one and the fame being; to that being, which he calls himself; a being, which he is led, by the conftitution of his nature, to confider as fomething diftinct from his body, and as not liable to be impaired by the lofs or mutilation of any of his organs. Effays on the Active Powers of Man, p. 8, 9. Introduction. FROM these confiderations, it appears, that we have the fame evidence for the existence of mind, that we have for the existence of body; nay, if there be any difference between the two cafes, that we have stronger evidence for it; inafmuch as the one is suggested to us, by the subjects of our own consciousness, and the other merely by the objects of our 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 abfolutely neceffary for the prefervation of our animal exiftence. 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 fame general laws; and that we acquire habits of inattention to the fubjects of our consciousness, too ftrong to be afterwards furmounted, without the most persevering industry. IF the foregoing obfervations be well founded, they establish the diftinction between mind and matter, without any long process of metaphyfical reasoning*: for if our notions of both are merely relative; if we know the one, only by fuch sensible qualities, as extension, figure, and folidity; and the other, by fuch operations as fenfation, thought, and volition; we are certainly entitled to say, that, in so far as body and mind are known to us, they appear to be substances of different natures. Perhaps, indeed, it would be more accurate to fay of the scheme See Note [A], at the end of the volume. of of materialism, that it is inconceivable, than that it is false;for let us confider only what it implies: Is it not the object of those who propofe it, to explain the nature of that fubftance which feels, thinks, and wills? But when they attempt to do fo, by faying that it is material, they furely forget, that body, as well as mind, is known to us by its qualities and attributes alone, and that we are as ignorant of the nature of the former, as of that of the latter *. As all our knowledge of the material world is derived from the information of our fenfes, Natural philofophers have, in modern times, wifely abandoned to Metaphyficians, all fpeculations concerning the nature of that fubftance of which it is composed; concerning the poffibility or impoffibility of its being created; concerning the efficient causes of the changes which take place in it; and even concerning the reality of its exiftence, independent of that of percipient beings and have confined themselves to the humbler province of obferving the phenomena it exhibits, and of afcertaining their general laws. By pursuing this plan steadily, they have, in the course of the two laft centuries, formed a body of science, which not only does honour * Some metaphysicians, who appear to admit the truth of the foregoing reafoning, have farther urged, that for any thing we can prove to the contrary, it is poffible, that the unknown substance which has the qualities of extenfion, figure, and colour, may be the fame with the unknown fubftance which has the attributes of feeling, thinking, and willing. But befides that this is only an hypothefis, which amounts to nothing more than a mere poffibility; even if it were true, it would no more be proper to fay of mind, that it is material, than to say of body, that it is spiritual. Introduction. to to the human understanding, but has had a most important influence on the practical arts of life. This experimental philofophy, no one now is in danger of confounding with the metaphyfical speculations already mentioned. Of the importance of these, as a separate branch of ftudy, it is poffible that fome 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 confequence to the evidence of this last fcience, that its principles fhould not be blended with thofe of the former. A SIMILAR diftinction 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 refides in the brain, or be spread over the body, by diffufion; are queftions perfectly analogous to those which metaphysicians have started on the fubject of matter. It is unneceffary to inquire, at present, whether or not they admit of answer. It is fufficient for my purpose to remark, that they are as widely and obviously different from the view, which I propose to take, of the human mind in the following work, as the reveries of Berkeley concerning the non-existence of the material world, are from the conclufions of Newton, and his followers.-It is farther evident, that the metaphyfical opinions, which we may happen to have formed concerning the nature either of body or of mind, and the efficient caufes by which their phenomena are produced, have no neceffary connexion with our inquiries concerning the laws, according to which these phenomena take place.—Whe |