[248] C’est en effet parler de Dieu comme d’un Jupiter ou d’un Saturne, et l’assujettir au Styx et aux destinées, que de dire que ces vérités sont indépendantes de lui. Ne craignez point, je vous prie, d’assurer et de publier partout que c’est Dieu qui a établi ces lois en la nature, ainsi qu’un roi établit les lois en son royaume. Vol. vi., p. 109. He argues as strenuously the same point in p. 132 and p. 307.
[249] Vol. ix., p. 369.
His just notion of definitions. 101. Descartes was perhaps the first who saw that definitions of words, already as clear as they can be made, are nugatory or impenetrable. This alone would distinguish his philosophy from that of the Aristotelians, who had wearied and confused themselves for twenty centuries with unintelligible endeavours to grasp by definition what refuses to be defined. “Mr Locke,” says Stewart, “claims this improvement as entirely his own, but the merit of it unquestionably belongs to Descartes, although it must be owned that he has not always sufficiently attended to it in his researches.”[250] A still more decisive passage to this effect, than that referred to by Stewart in the Principia will be found in the posthumous dialogue on the Search after Truth. It is objected by one of the interlocutors, as it had actually been by Gassendi, that, to prove his existence by the act of thinking, he should first know what existence and what thought is. “I agree with you,” the representative of Descartes replies, “that it is necessary to know what doubt is, and what thought is, before we can be fully persuaded of this reasoning; I doubt, therefore I am, or what is the same, I think, therefore I am. But do not imagine that for this purpose you must torture your mind to find out the next genus, or the essential differences, as the logicians talk, and so compose a regular definition. Leave this to such as teach or dispute in the schools. But whoever will examine things by himself, and judge of them according to his understanding, cannot be so senseless as not to see clearly, when he pays attention, what doubting, thinking, being, are, and as to have any need to learn their distinctions. Besides, there are things which we render more obscure, in attempting to define them, because, as they are very simple and very clear, we cannot know and comprehend them better than by themselves. And it should be reckoned among the chief errors that can be committed in science for men to fancy that they can define that which they can only conceive, and distinguish what is clear in it from what is obscure, while they do not see the difference between that which must be defined before it is understood and that which can be fully known by itself. Now, among things which can thus be clearly known by themselves, we must put doubting, thinking, being. For I do not believe any one ever existed so stupid as to need to know what being is before he could affirm that he is; and it is the same of thought and doubt. Nor can he learn these things except by himself, nor be convinced of them but by his own experience, and by that consciousness and inward witness which every man finds in himself when he examines the subject. And as we should define whiteness in vain to a man who can see nothing, while one can open his eyes and see a white object requires no more, so to know what doubting is, and what thinking is, it is only necessary to doubt and to think.”[251] Nothing could more tend to cut short the verbal cavils of the schoolmen, than this limitation of their favourite exercise, definition. It is due, therefore, to Descartes, so often accused of appropriating the discoveries of others, that we should establish his right to one of the most important that the new logic has to boast.
[250] Dissertation, ubi, suprá, Stewart, in his Philosophical Essays, note A, had censured Reid for assigning this remark to Descartes and Locke, but without giving any better reason than that it is found in a work written by Lord Stair; earlier, certainly, than Locke, but not before Descartes. It may be doubtful, as we shall see hereafter, whether Locke has not gone beyond Descartes, or at least distinguished undefinable words more strictly.
[251] Vol. xi., p. 369.
His notion of substances. 102. He seems, at one moment, to have been on the point of taking another step very far in advance of his age. “Let us take,” he says, “a piece of wax from the honey-comb; it retains some taste and smell, it is hard, it is cold, it has a very marked colour, form, and size. Approach it to the fire; it becomes liquid, warm, inodorous, tasteless; its form and colour are changed, its size is increased. Does the same wax remain after these changes? It must be allowed that it does; no one doubts it, no one thinks otherwise. What was it then that we so distinctly knew to exist in this piece of wax? Nothing certainly that we observed by the senses, since all that the taste, the smell, the sight, the touch reported to us has disappeared, and still the same wax remains.” This something which endures under every change of sensible qualities cannot be imagined; for the imagination must represent some of these qualities, and none of them are essential to the thing; it can only be conceived by the understanding.[252]
[252] Méditation Seconde, i. 256.
Not quite correct. 103. It may seem almost surprising to us, after the writings of Locke and his followers on the one hand, and the chemist with his crucible on the other, have chased these abstract substances of material objects from their sanctuaries, that a man of such prodigious acuteness and intense reflection as Descartes should not have remarked that the identity of wax after its liquefaction is merely nominal, and depending on arbitrary language, which in many cases gives new appellations to the same aggregation of particles after a change of their sensible qualities; and that all we call substances are but aggregates of resisting moveable corpuscles, which by the laws of nature are capable of affecting our senses differently, according to the combinations they may enter into, and the changes they may successively undergo. But if he had distinctly seen this, which I do not apprehend that he did, it is not likely that he would have divulged the discovery. He had already given alarm to the jealous spirit of orthodoxy by what now appears to many so self-evident, that they have treated the supposed paradox as a trifling with words, the doctrine that colour, heat, smell, and other secondary qualities, or accidents of bodies, do not exist in them, but in our own minds, and are the effects of their intrinsic or primary qualities. It was the the tenet of the schools that these were sensible realities, inherent in bodies; and the church held as an article of faith, that the substance of bread being withdrawn from the consecrated wafer, the accidents of that substance remained as before, but independent, and not inherent in any other. Arnauld raised this objection, which Descartes endeavoured to repel by a new theory of transubstantiation; but it always left a shade of suspicion, in the Catholic church of Rome, on the orthodoxy of Cartesianism.
His notions of intuitive truth. 104. “The paramount and indisputable authority which, in all our reasonings concerning the human mind, he ascribes to the evidence of consciousness” is reckoned by Stewart among the great merits of Descartes. It is certain that there are truths which we know, as it is called, intuitively, that is, by the mind’s immediate inward glance. And reasoning would be interminable, if it did not find its ultimate limit in truths which it cannot prove. Gassendi imputed to Descartes, that, in his fundamental enthymem, Cogito, ergo sum, he supposed a knowledge of the major premise, Quod cogitat, est. But Descartes replied that it was a great error to believe that our knowledge of particular propositions must always be deduced from universals, according to the rules of logic; whereas, on the contrary, it is by means of our knowledge of particulars that we ascend to generals, though it is true that we descend again from them to infer other particular propositions.[253] It is probable that Gassendi did not make this objection very seriously.
[253] Vol. ii., p. 305. See too the passage, quoted above, in his posthumous dialogue.