The defection being thus begun, the revolt soon be came general. The method of induction recommend ed by the powel•ul genius of Bacon, completely under mined the authority of Aristotle in physical researches ; and Descartes soon began to think for himself, and to devise a new method of studying the philosophy of the human mind. The first thing he did was, to dismiss from his mind all reverence for any preceding doctrines and opinions. He went farther still, for he attempted to discard all previous belief which was not established on demonstration. The first point, then, was to ascer tain the reality of his own existence ; and we should think it would not have been very easy to have done this to the satisfaction of a man who seriously doubted of it. He satisfied himself on this point, however, by reflecting, that what thinks, must exist. Repugnat CniM ut putemus id quod cogitat eo ipso tempore quo cogitat non existere. .4c proinde beet cognitio, ego cogito, ergo sum, est omnium prima et certissima, quit cuilibet ordine philosophanti occurrat. Having thus satisfied himself of his own existence, he next proceeds to examine what evidence he has for the existence of any other object or substance besides himself. He had been accustomed to believe in an external world ; on reflection, however, he found that all he knew of that world was in him self ; and therefore he was entitled to doubt the reality of its existence ; because some superior being might have desired to deceive him. But he is sure he cannot be deceived as to the axiom by which he proves his own existence. Fallat me quisquis potest, nunquam tamen efficiet zit nihil situ quamdiu me aliquid ease cogita bo. After the utmost reflection, he finds that he had believed the existence of external objects only taco ali quo impulsu ; and he now proceeds to search for argu ments. And, first, he satisfies himself that there is a God ; for he can form a clear idea of his perfections ; perfections which he knows do not exist in himself; but since he entertains the idea of them, there must be an archetype of that idea ; and this carries him at once to the Supreme Being, as possessing all the attributes which he had conceived or him.
His reasoning is ingenious, and we shall give it in his own words : ‘• Quia Dei, sive ends summi ideam ha berries in nobis, jure possumus examinare, a quanain causa illam hdbeamus: tantamque in ea immensitatem inveniemus, ut plane ex en slums certi, non posse il!am nobis fuisse inditam, nisi a re, in qua sit revera omnium perfectionum complementum, hoc est, nisi a Deo reali ter existente. Est enim lumine naturali notissimum, non modo a itihilo uihil Seri; ncc id quod est perfectius ab en quod est minus perfectum, ut a causa efliciente et totali produci; sed neque etiam in nobis ideam sive imaginem ullius rei esse posse, cujus non alicubi, sive in nobis ipsis, sive extra nos, archetypus aliquis omnes ejus pei fectiones reipsa contincns, existat. Et quia summas illas perlectiones, quarum ideam habemus, nul lo modo in nobis reperimus, ex hoc ipso recte concludi mus eas in aliquo a nobis diverso, nempe in deo, esse ; yel certe aliquando fuisse, ex quo evidentissime se quitur, ipsas adhuc esse." Princip. Philosoph.pars prima.
This is perhaps as good an a priori argument for the existence of a God as Dr. Clarke's; and indeed, in some respects, it is not unlike it. Dr. Clarke seems to have borrowed his argument from the following passage in Newton's Principia : " Eternus est et infinitus, omnipo tens, et omnisciens; id est durat ab eterno in eternuin, et adest ab infinito in infinitum. Non est eternitas et infi nitas, sed eternus et infinitus; non est duratio et spatium, sed durat et adest. Durat semper, et adest ubique ; et existendo semper et ubique durationem et spatium con stituit." We would have willingly travelled out of our
way, at any time, to exhibit such a sublime specimen of metaphysical theology. Dr. Clarke has made the fol lowing use of it : Space and time, he observes, are only abstract conceptions of an immensity and eternity, which force themselves on our belief; and as immensity and eternity are not substances, they must be the attributes of a Being who is necessarily immense and eternal. We shall by and by examine the foundation of this ar gument.
Descartes haying satisfied himself as to the existence of a God, no longer hesitates in acknowledging the reality of an external world ; for lie concludes that the God whom he serves will not deceive him ; as a desire to deceive can only proceed from malice, or fear, or weakness ; none of which qualities can ever apply to God.
Descartes adopted the common theory respecting per ception. Till his day, and long after it, nobody doubt ed that certain images were propagated from bodies, in some unaccountable manner, which produced ideas in the mind. Aristotle, as we have already stated, illus trates this, by saying that the senses receive sensible species, or forms, without matter, as wax receives the impression of a seal, without receiving any part of the substance. The received maxim among the Peripate tics, and we do not see how it can be disputed, is, that no thing can act where it is not ; and therefore, if matter be different from mind, there must be some medium interposed to bring them, as it were, into contact. This opinion has given rise to a variety of theories half me taphysical, hall physiological, such as that of animal spirits, or as the vibrations of Ilartley, and the like, with a view to explain the way in which the immaterial sub stance of the soul is acted upon by external objects. We conceive all such attempts to be futile; nor can we Form any conception of contact between a material and an immaterial substance ; or of the manner in which body acts on spirit, or this on material substances. An author of sonic celebrity,* has advanced a very extraor dinary hypothesis to explain this mysterious subject ; we shall give a part of it in his own words, to caution our readers against the danger of theorizing: Were I permitted to conjecture in a matter where nothing bet ter than conjecture can be had, I should suppose spirit naturally penetrable, but capable of rendering itself so lid upon occasion, with respect to particular bodies, and that hereon our activity depends. I have formerly given my reasons for imagining, that the force where with we move our limbs, is derived from the animal circulation rushing into the muscles through certain nerves, and that the orifices of these nerves arc provid ed with stoppers, which the mind draws up at pleasure to give the animal spirits admittance ; now what should hinder our conceiving these stoppers pushed up by lit tle hairs, or fibres, whose other ends lie within our spiritual part,t which by its natural penetrability, ad mits them into the space where it resides ? But, upon the mind rendering itself solid with respect to any par ticular fibre, it is driven forward, thereby lifts up the stopper, and opens the passage into the nerves; until volition, forbearing to act, the penetrability returns— the fibre, no longer pressed, falls back to its former sta tion, the stopper following, closes the passage, and mus cular motiun ceases." The author proceeds in the same style ; but we have given enough to exhibit a complete specimen of me taphysical absurdity, or rather of the danger which must always attend physiologico•metaphysical speculations.