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IV.— The Consideration of the inductive Logic resumed
1. Additional Remarks on the distinction between Experience and
Analogy.—of the grounds afforded by the latter for Scientific
Inference and Conjecture
11. Use and Abuse of Hypothesis in Philosophical Inquiries.-Differ-
ence between Gratuitous Hypotheses, and those which are sup.
ported by presumptions suggested by Analogy.-indirect Evi-
dence which a Hypothesis may derive from its agreement with
the Phenomena. -Cautions against extending some of these con-
clusions to the Philosophy of the Human mind
11. Supplemental Observations on the words Induction and Analogy,
as used in Mathematics
V.–Of certain misapplications of the words Experience and Induction
in the phraseology of Modern Science. - Illustrations from Me.
dicine and from Political Economy
v1.-Of the Speculation concerning Final Causes
1. Opinion of Lord Bacon on the subject. Final Causes rejected by
Des Cartes, and by the majority of French Philosophers.-Re-
cognised as legitimate Objects of research by Newton.-Tacitly
acknowledged by all as a useful Logical Guide, even in Sciences
which have no immediate relation to Theology
11. Danger of confounding Final with Physical Causes in the Philoso-
phy of the Human Mind
Conclusion of Part Second
Of the Nature and Object of the Philosophy of the Human Mind.
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 inconsi derable 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 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 prin
ciples 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 notion we annex to the words, matter and mind, as is well remarked by Dr. Reid, (in his Essays on the Active Powers of Man,) 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, colored, movable, 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, color, and certain other qualities, which the constitution of my nature leads me to refer to something, which is extended, figured, and colored. The case is precisely similar with respect to mind. We are not iinmediately 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.
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 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 endeavor to refer them to the same general laws; and that we acquire habits of inattention to the subjects of our consciousness, too strong to be afterwards surmounted, without the most persevering industry.
If the foregoing observations be well founded, they establish the distinction between mind and matter, without any long process of metaphysical reasoning :* for if our notions of both are merely relative; if we know the one, only by such sensible qualities as extension, figure, and solidity; and the other, by such operations as sensation, thought, and volition; we are certainly entitled to say, that matter and mind, considered as objects of human study, are essentially different; the science of the former resting ultimately on the phenomena exhibited to our senses; that of the latter, on the phenomena of which we are conscious. Instead, therefore, of objecting to the scheme of materialism, that its conclusions are
* I am happy in being able to quote the following passage, in illustration of a doctrine, against which I do not conceive it possible to urge any thing, but the authority of some illustrious names.
" Puisque l'existence des corps n'est pour nous que la permanence d'êtres dont
les propriétés répondent à un certain ordre de nos sensations, il en résulte qu'elle n'a rien de plus certain que celle d'autres êtres qui se manifestent également par leurs effets sur nous; et puisque nos observations sur nos propres facultés, confirmées par celles que nous faisons sur les êtres pensants qui animent aussi des corps, ne nous montrent aucune analogie entre l'être qui sent ou qui pense et l'être qui nous offre le phénomène de l'étendue ou de l'impénétrabilité, il n'y a aucune raison de croire ces êtres de la même nature. Ainsi la spiritualité de l'ame n'est pas une opinion qui ait besoin de preuves, mais le résultat simple et naturel d'une analyse exacte de nos idées, et de nos facultés.”– Vie de M. Turgot, par M. Condorcet.
Des Cartes was the first philosopher who stated, in a clear and satisfactory manner, the distinction between mind and matter, and who pointed out the proper plan for studying the intellectual phenomena. It is chiefly in consequence of his precise ideas with respect to this distinction, that we may remark, in all his metaphysical writings, a perspicuity which is not observable in those of any of his predecessors.
Dr. Reid has remarked, that although Des Cartes infers the existence of mind, from the operations of which we are conscious, yet he could not reconcile himself to the notion of an unknown substance, or substratum, to which these operations belonged. And it was on this account, he conjectures, that he made the essence of the soul to consist in thought; as, for a similar reason, he had made the essence of matter to consist in extension. But I am afraid, that this supposition is not perfectly reconcilable with Des Cartes' writings; for he repeatedly speaks with the utmost confidence of the existence of substances of which we have only a relative idea ; and, even in attempting to show that thought is the essential atiri. bute of mind, and extension of matter, he considers them as nothing more than attributes or qualities belonging to these substances.
“ Per substantiam nihil aliud intelligere possumus, quam rem quæ ita existit, ut nulla alia re indigeat ad existendum. Et quidem substantia quæ nulla plane nisi ope concursus Dei existere posse percipimus. Atque ideo nomen substantiæ non convenit Deo et illis univoce ut dici solet in scholis ; hoc est, nulla ejus nominis significatio, potest distincte intelligi, quæ Deo, et creaturis sit communis.
“ Possunt autem substantia corporea, et mens, sive substantia cogitans, creata, sub hoc communi conceptu intelligi; quod sint res, quæ solo Dei concursu egent ad existendum. Verumtamen non potest substantia primum animadverti ex hoc solo, quod sit res existens, quia hoc solum per se nos non afficit: sed facile ipsam agnoscimus ex quodlibet ejus attributo, per communem illam notionem, quod nihili nulla sunt attributa, nullæve proprietates aut qualitates. Ex hoc enim, quod aliquod attributum adesse percipiamus, concludimus aliquam rem existentem, sive substantiam cui illud tribui possit, necessario etiam adesse.
« Et quidem ex quolibet attributo substantia cognoscitur : sed una tamen est cujusque substantiæ præcipua proprietas, quæ ipsius naturam essentiamque constituit, et ad quam aliæ omnes referuntur. Nempe extensio in longum, latum et profundum substantiæ corporeæ naturam constituit; et cogitatio constituit naturam substantiæ cogitantis.”—Princip. Philosoph. pars i. cap. 51–53.
In stating the relative notions which we have of mind and of body, I have avoided the use of the word substance, as I am unwilling to furnish the slightest occasion for controversy ; and have contented myself with defining mind to be that which feels, thinks, wills, hopes, fears, desires, &c. That my consciousness of these and other operations is necessarily accompanied with a conviction of my own existence, and with a conviction that all of them belong to one and the same being, is not an hypothesis, but a fact; of which it is no more possible for me to doubt, than of the reality of my own sensations or volitions.
false, it would be more accurate to say, that its aim is unphilosophical. It proceeds on a misapprehension of the proper object of science; the difficulty which it professes to remove being manifestly placed beyond the reach of our faculties. Surely, when we attempt to explain the nature of that principle which feels and thinks and wills, by saying, that it is a material substance, or that it is the result of material organization, we impose on ourselves by words; forgetting, that matter as well as mind is known to us by its qualities and attributes alone, and that we are totally ignorant of the essence of either.*
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 metaphysicians, 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 honor 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 favorably 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, which I propose to take, of the human mind in the following work, as the reveries of Berkeley concerning the nonexistence of the material world, are from the
* Some metaphysicians, who appear to admit the truth of the foregoing reasoning, have farther urged, that for any thing we can prove to the contrary, it is possible, that the unknown substance which has the qualities of extension, figure, and color, 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 proper to say of mind, that it is material, than to say of body, that it is spiritual.