« PredošláPokračovať »
La's happy in being able to quote the following passage, in illustration of a doctrine, against which I do not conceive it possible to urge anything, 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'âme 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.
Descartes 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 Descartes 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 Descartes' 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 shew that thought is the essential attribute 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 re indigeat, unica tantum potest intelligi, nempe Deus. Alias vero omnes, non nisi ope concursus Dei existere posse percipimus. Atque ideo nomen substantiae 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, bub 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, quid hoc solum per se nos non afficit: sed facile ipsam agnoscimus ex quolibet 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 ex'ensio in longum, latum et profundum substantiæ corporeæ naturam constituit; et cogitatio constituit paturam substantiæ cogitantis.”—Princip. Philosoph., pars i. cap. 51-53.
In stating the relative notions which we have of mind and of body, I hare 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 a 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.
Note B, p. 94.— External Perception. ( 1.) Dr. Reid remarks, that Descartes rejected a part only of the ancient theory of perception, and adopted the other part. “That theory," says he, “may be divided into two parts: the first, that images, species, or forms, of external objects, come from the object, and enter by the avenues of the senses to the mind; the second part is, that the external object itself is not perceived, but only the species or image of it in the mind. The first part, Descartes and his followers rejected and refuted by solid arguments, but the second part, neither he nor his followers have thought of calling in question, being persuaded that it is only a representative image in the mind of the external object that we perceive, and not the object itself. And this image, which the peripatetics called a species, he calls an idea, changing the name only, while he admits the thing."
The account which this passage contains of Descartes' doctrine concerning per. ception, is, I believe, agreeable to his prevailing opinion, as it may be collected from the general tenor of his wr gs; and the observation with which it concludes is undoubtedly true, that neither he nor any of his followers erer called in question the existence of ideas, as the immediate objects of our perception. With respect, however, to the first part of the ancient theory, as here stated, it may be proper to remark that Descartes, although evidently by no means satisfied with it, gometimes expresses hinself as if he rather doubted of it, than expressly denied it; and at other times, when pressed with objections to his own particular system, he admits, at least in part, the truth of it. The following passage is one of the niost explicit I recollect, in opposition to the ancient doctrine :
"Observandum præterea, animam, nullis imaginibus ab objectis ad cerebrum missis egere ut sentiat, (contra quam communiter philosophi nostri statuunt,) aut ad minimum longe aliter illarum imaginum naturam concipiendam esse quam vulgo fit. Quum enim circa eas nil considerent, præter similitudinem earum cum objectis qnæ repræsentant, non possunt explicare, qua ratione ab objectis formari queant, et recipi ab organis sensuum exteriorum, et demum nervis ad cerebrum transvehi. Nec alia causa imagines istas fingere eos impulit, nisi quod viderent mentem nostram efficaciter pictura excitari ad apprehendendum objectum illud, quod exhibet : ex hoc enim judicarunt, illam eodem modo excitandam, ad apprehendenda ea quæ sensus movent, per exiguas quasdam imagines, in capite nostro delineatas. Sed nobis contra est advertendum, multa præter imagines esse, quæ cogitationes excitant, ut exempli gratia, verba et signa, nullo modo similia iis quæ significant."-Dioptr. cap. 4. sect. 6.
In his third Meditation, (which contains his celebrated argument for the existence of a Deity,) the following passage occurs :
Sed bic præcipue de iis est quærendum quas tanquam a rebus extra me existentibus desumptas considero, quænam me moveat ratio ut illas istis rebus similes esse existimem ; nempe ita videor doctus a natura, et præterea experior illas non a mea voluntate nec proinde a me ipso pendere, sæpe enim vel invito obversantur, ut jam, sive velim sive nolim, sentio calorem, et ideo puto sensum illum, sive ideam caloris a re a me diversa, nempe ab ignis cui assideo calore mihi advenire, nihilque magis obvium est, quam ut judicem istam rem suam similitudinem potius, quam aliud quid in me immittere ; quæ rationes an satis firmæ sint, jam videbo. Cum hic dico me ita doctum esse a natura, intelligo tantum spontaneo quodam impetu me ferri ad hoc credendum, non lumine aliquo naturali mihi ostendi esse verum, quæ duo multum discrepant, nam quæcumque lumine naturali mihi ostend. untur, (ut quod ex eo quod dubitem sequatur me esse, et similia,) nullo modo dubia esse possunt, quia nulla alia facultas esse potest, cui æque fidam ac lumini isti, quæque illa non vera possit docere; sed quantum ad impetus naturales, jam sæpe olim judicavi me ab illis in deteriorem partem fuisse impulsum cum de bono eligendo ageretur, nec video cur iisdem in ulla alia re magis fidam. Deinde quamvis ideæ illæ a voluntate mea non pendeant, non ideo constat ipsas a rebus extra me positis necessario procedere; ut enim impetus illi, de quibus mox loquebar, quamvis in me sint, a voluntate tamen mea diversi esse videntur, ita forte etiam aliqua alia est in me facultas nondum mihi satis cognita istarum idearum effectrix, ut hactenus semper visum est illas, dum somnio, absque ulla rerum externarum ope in me formari; ac denique quamvis a rebus a me diversis procederent, non inde sequitur illas rebus istis similes esse debere ; quinimo in multis sæpe magnum discrimen videor deprehendisse ; sic, exempli causa, duas diversas solis ideas apud me invenio, unam tanquam a sensibus haustam, et quæ maxime inter illas quas adventitias existimo est recensenda, per quam mihi valde parvus apparet; aliam vero ex rationibus astronomiæ desumptam, hoc est ex notionibus quibusdam mihi innatis elicitam vel quocumque alio modo a me factam, per quam aliquoties major
quam terra exhibetur; utraque profecto similis eidem soli extra me existenti esse non potest, et ratio persuadet illam ei maxime esse dissimilem, quæ quam proxime ab ipso videtur emanâsse. Quæ omnia satis demonstrant me non hactenus ex certo judicio, sed tantum ex cæco aliquo impulsu credidisse res quasdam a me diversas existere, quæ ideas sive imagines suas per organa sensuum, vel quolibet alio pacto mihi immittant.”—[Editio Amstelod., 1658, p. 19.]
Among other animadversions upon this meditation sent to Descartes by one of his correspondents, [Gassendi,] it is objected :-“Videris vertere in dubium non tantum utrum ideæ aliquæ procedant ex rebus externis, sed etiam utrum omnino sint externæ res aliquæ." To which Descartes answers,—"Notandum est, me non affirmâsse ideas rerum materialium ex mente deduci, ut non satis bona fide hic fingis; expresse enim postea ostendi ipsas a corporibus sæpe advenire, ac per hoc corporum existentiam probari.”—Vide Objectiones (Quintas et Septimas) in Meditationes Renati Descartes, cum ejusdem ad illas Responsionibus ; [ą 3 et 6, ed. 1657, pp. 21, 79.]
Note C, p. 97.—External Perception. (8 2.) In consequence of the inferences which Mr. Hume has deduced from this doctrine concerning Cause and Effect, some later authors have been led to dispute its truth; not perceiving that the fallacy of this part of Mr. Hume's system does not consist in his premises, but in the conclusion which he draws from them.
That the object of the physical inquirer is not to trace necessary connexions, or to ascertain the efficient causes of phenomena, is a principle which has been frequently ascribed to Mr. Hume as its author, both by his followers and by his opponents; but it is in fact of a much earlier date, and has been maintained by many of the most enlightened and the least sceptical of our modern philosophers; nor do I know that it was ever suspected to have a dangerous tendency, till the publication of Mr. Hume's writings. "If we except," says Dr. Barrow, "the mutual causality and dependence of the terms of a mathematical demonstration, I do not think that there is any other causality in the nature of things, wherein a necessary consequence can be founded. Logicians do indeed boast of I do not know what kind of demonstrations from external causes either efficient or final, but without being able to shew one genuine example of any such ; nay, I imagine it is impossible for them so to do. For there can be no such connexion of an external efficient cause with its effect,” (at least none such can be understood by us,) " through which, strictly speaking, the effect is necessarily supposed by the supposition of the efficient cause, or any determinate cause by the supposition of the effect.” He adds afterwards, “ Therefore there can be no argumentation from an efficient cause to the effect, or from an effect to the cause which is lawfully necessary.”—Mathematical Lectures read at Cambridge.
Dr. Butler, too, in his discourse on the ignorance of man, has remarked, that “it is in general no more than effects that the most knowing are acquainted with; for as to causes they are entirely in the dark the most ignorant." What are the laws," he continues, " by which matter acts on matter, but certain effects which some having observed to be frequently repeated, have reduced to general rules ?"-Butler's Sermons.
" The laws of attraction and repulsion," says Dr. Berkeler, "are to be regarded
as laws of motion, and these only as rules or methods observed in the productions of natural effects, the efficient and final causes whereof are not of mechanical consideration. Certainly if the explaining a phenomenon be to assign its proper efficient and final cause, it should seem the mechanical philosophers never explained anything; their province being only to discover the laws of nature ; that is, the general rules and method of motion ; and to account for particular pheno
1 mena by reducing them under, or shewing their conformity to such general rules." -Siris: or, Philosophical Inquiries concerning the Virtues of Tar Water, p. 108, [S 231.]
" The words attraction and repulsion may, in compliance with custom, be used where, accurately speaking, motion alone is meant."-Ibid. p. 114, (S 240.]
“Attraction cannot produce, and in that sense account for the phenomena ; being itself one of the phenomena produced and to be accounted for.”—Ibid. p. 115, (S 243.]
" There is a certain analogy, constancy, and uniformity in the phenomena or appearances of nature, which are a foundation for general rules; and these are a grammar for the understanding of nature, or that series of effects in the visible world whereby we are enabled to foresee what will come to pass in the natural course of things. Plotinus observes in his third Ennead, that the art of presaging is in some sort the reading of natural letters denoting order, and that so far forth as analogy obtains in the universe, there may be vaticination. And in reality he that foretells the motions of the planets, or the effects of medicines, or the result of chemical or mechanical experiments, may be said to do it by natural vaticination.” --Ibid. pp. 120, 121, [S 252.]
Instruments, occasions, and signs, occur in, or rather make up, the whole visible course of nature.”—Ibid. p. 123, (S 258.]*
The following very remarkable passage from Mr. Locke shews clearly, that this eminent philosopher considered the connexion between impulse and motion as a conjunction which we learn from experience only; and not as a consequence deducible from the consideration of impulse by any reasoning a priori. The passage is the more curious, that it is this particular application of Mr. Hume’s doctrine that has been generally supposed to furnish the strongest objection against it.
“Another idea we have of body, is the power of communicating motion by impulse ; and of our souls, the power of exciting motion by thought. These ideas, the one of body, the other of our minds, every-day's experience clearly furnishes us with ; but if here again we inquire how this is done, we are equally in the dark. For in the communication of motion by impulse, wherein as much motion is lost to one body as is got to the other, which is the ordinariest case, we can have no other conception but of the passing of motion out of the one into another, which I think is as obscure and inconceivable, as how our minds move or stop our bodies by thought, which we every moment find they do." . ... "The communication of motion by thought, which we ascribe to spirit, is as evident as that of impulse, which we ascribe to body. Constant experience makes us sensible of both of these, though our narrow understandings can comprehend neither.”
* See further of the Siris, $3 154, 155, 220, and of his Treatise De Motu, $$ 3, 5, 8, 19, 21, 231, 234, 243, 247, 250, 252, 254, 258; Berke- 22, 23, 25, 30, 32, 35, 48, 69, 71, &c., &c.ley's Principles of Human Knoncledge, &$ 55, 56; Ed.