thought alone; which is thus known earlier and more certainly than any corporeal thing.”[157] ‘I’ has thus significance here as thought, and not as individuality of self-consciousness. The second proposition of the Cartesian philosophy is hence the immediate certainty of thought.
Certainty is only knowledge as such in its pure form as self-relating, and this is thought; thus then the unwieldy understanding makes its way on to the necessity of thought.
Descartes begins, just as Fichte did later on, with the ‘I’ as indubitably certain; I know that something is presented in me. By this Philosophy is at one stroke transplanted to quite another field and to quite another standpoint, namely to the sphere of subjectivity.
Presuppositions in religion are given up; proof alone is sought for, and not the absolute content which disappears before abstract infinite subjectivity. There is in Descartes likewise a seething desire to speak from strong feeling, from the ordinary sensuous point of view, just as Bruno and so many others, each in his own fashion, express as individualities their particular conceptions of the world. To consider the content in itself is not the first matter; for I can abstract from all my conceptions, but not from the ‘I.’ We think this and that, and hence it is—is to give the common would-be-wise argument of those incapable of grasping the matter in point; that a determinate content exists is exactly what we are forced to doubt—there is nothing absolutely fixed. Thought is the entirely universal, but not merely because I can abstract, but because ‘I’ is thus simple, self-identical. Thought consequently comes first; the next determination arrived at, in direct connection with it, is the determination of Being. The ‘I think’ directly involves my Being; this, says Descartes, is the absolute basis of all Philosophy.[158] The determination of Being is in my ‘I’; this connection is itself the first matter. Thought as Being and Being as thought—that is my certainty, ‘I’; in the celebrated _Cogito, ergo sum_ we thus have Thought and Being inseparably bound together.
On the one hand this proposition is regarded as a syllogism: from thought Being is deduced. Kant more especially has objected to this that Being is not contained in thinking, that it is different from thinking. This is true, but they are still inseparable, or constitute an identity; their difference is not to the prejudice of their unity. Yet this maxim of pure abstract certainty, the universal totality in which everything implicitly exists, is not proved;[159] we must therefore not try to convert this proposition into a syllogism. Descartes himself says: “There is no syllogism present at all. For in order that there should be such, the major premise must have been ‘all that thinks exists’”—from which the subsumption would have followed in the minor premise, ‘now I am.’ By this the immediacy which rests in the proposition, would be removed. “But that major premise” is not set forth at all, being “really in the first instance derived from the original ‘I think, therefore, I am.’”[160] For arriving at a conclusion three links are required—in this case we ought to have a third through which thought and Being should have been mediated, and it is not to be found here. The ‘Therefore’ which binds the two sides together is not the ‘Therefore’ of a syllogism; the connection between Being and Thought is only immediately posited. This certainty is thus the _prius_; all other propositions come later. The thinking subject as the simple immediacy of being-at-home-with-me is the very same thing as what is called Being; and it is quite easy to perceive this identity. As universal, thought is contained in all that is particular, and thus is pure relation to itself, pure oneness with itself. We must not make the mistake of representing Being to ourselves as a concrete content, and hence it is the same immediate identity which thought likewise is. Immediacy is, however, a one-sided determination; thought does not contain it alone, but also the determination to mediate itself with itself, and thereby—by the mediation being at the same time the abrogation of the mediation—it is immediacy. In thought we thus have Being; Being is, however, a poor determination, it is the abstraction from the concrete of thought. This identity of Being and Thought, which constitutes the most interesting idea of modern times, has not been further worked out by Descartes; he has relied on consciousness alone, and for the time being placed it in the fore-front. For with Descartes the necessity to develop the differences from the ‘I think’ is not yet present; Fichte first applied himself to the deduction of all determinations from this culminating point of absolute certainty.
Other propositions have been set against that of Descartes.
Gassendi,[161] for example, asks if we might not just as well say _Ludificor, ergo sum_: I am made a fool of by my consciousness, therefore I exist—or properly speaking, therefore I am made a fool of. Descartes himself recognized that this objection merited consideration, but he here repels it, inasmuch as it is the ‘I’ alone and not the other content which has to be maintained. Being alone is identical with pure thought, and not its content, be it what it may. Descartes further says: “By thought I, however, understand all that takes place in us within our consciousness, in as far as we are conscious of it; thus will, conception, and even feeling are identical with thought. For if I say ‘I see,’ or ‘I walk out,’ and ‘therefore I am,’ and understand by this the seeing and walking which is accomplished by the body, the conclusion is not absolutely certain, because, as often happens in a dream, I may imagine that I can see or walk even if I do not open my eyes nor move from my place, and I might also possibly do so supposing I had no body.
But if I understand it of the subjective feeling or the consciousness of seeing or walking itself, because it is then related to the mind that alone feels or thinks that it sees or walks, this conclusion is perfectly certain.”[162] “In a dream” is an empirical mode of reasoning, but there is no other objection to it. In willing, seeing, hearing, &c., thought is likewise contained, it is absurd to suppose that the soul has thinking in one special pocket, and seeing, willing, &c., in others. But if I say ‘I see,’ ‘I walk out,’ there is present on the one hand my consciousness ‘I,’ and consequently thought, on the other hand, however, there is present willing, seeing, hearing, walking, and thus a still further modification of the content. Now because of this modification I cannot say ‘I walk, and therefore I am,’ for I can undoubtedly abstract from the modification, since it is no longer universal Thought. Thus we must merely look at the pure consciousness contained in the concrete ‘I.’ Only when I accentuate the fact that I am present there as thinking, is pure Being implied, for only with the universal is Being united.
“In this it is implied,” says Descartes, “that thought is more certain to me than body. If from the fact that I touch or see the earth I judge that it exists, I must more certainly judge from this that my thought exists.
For it may very well happen that I judge the earth to exist, even if it does not exist, but it cannot be that I judge this, and that my mind which judges this does not exist.”[163] That is to say, everything which is for me I may assert to be non-existent, but when I assert myself to be non-existent, I myself _assert_, or it is _my_ judgment. For I cannot set aside the fact that I judge, even if I can abstract from that respecting which I judge. In this Philosophy has regained its own ground that thought starts from thought as what is certain in itself, and not from something external, not from something given, not from an authority, but directly from the freedom that is contained in the ‘I think.’ Of all else I may doubt, of the existence of bodily things, of my body itself; or this certainty does not possess immediacy in itself. For ‘I’ is just certainty itself, but in all else this certainty is only predicate; my body is certain to _me_, it is not this certainty itself.[164] As against the certainty we feel of having a body, Descartes adduces the empirical phenomenon that we often hear of persons imagining they feel pain in a limb which they have lost long ago.[165] What is actual, he says is a substance, the soul is a thinking substance; it is thus for itself, separate from all external material things and independent. That it is thinking is evident from its nature: it would think and exist even if no material things were present; the soul can hence know itself more easily than its body.[166] All else that we can hold as true rests on this certainty; for in order that anything should be held as true, evidence is requisite, but nothing is true which has not this inward evidence in consciousness. “Now the evidence of everything rests upon our perceiving it as clearly and vividly as that certainty itself, and on its so entirely depending from, and harmonizing with this principle, that if we wished to doubt it we should also have to doubt this principle likewise” (our _ego_).[167] This knowledge is indeed on its own account perfect evidence, but it is not yet the truth, or if we take that Being as truth, it is an empty content, and it is with the content that we have to do.
c. What comes third is thus the transition of this certainty into truth, into the determinate; Descartes again makes this transition in a naïve way, and with it we for the first time begin to consider his metaphysics. What here takes place is that an interest arises in further representations and conceptions of the abstract unity of Being and Thought; there Descartes sets to work in an externally reflective manner. “The consciousness which merely knows itself to be certain now however seeks to extend its knowledge, and finds that it has conceptions of many things—in which conceptions it does not deceive itself, so long as it does not assert or deny that something similar outside corresponds to them.” Deception in the conceptions has meaning only in relation to external existence. “Consciousness also discovers universal conceptions, and obtains from them proofs which are evident, _e.g._ the geometric proposition that the three angles of a triangle are together equal to two right angles is a conception which follows incontrovertibly from others.
But in reflecting whether such things really exist doubts arise.”[168] That there is such a thing as a triangle is indeed in this case by no means certain, since extension is not contained in the immediate certainty of myself. The soul may exist without the bodily element, and this last without it, they are in reality different; one is conceivable without the other. The soul thus does not think and know the other as clearly as the certainty of itself.[169] Now the truth of all knowledge rests on the proof of the existence of God. The soul is an imperfect substance, but it has the Idea of an absolute perfect existence within itself; this perfection is not begotten in itself, just because it is an imperfect substance; this Idea is thus innate. In Descartes the consciousness of this fact is expressed by his saying that as long as the existence of God is not proved and perceived the possibility of our deceiving ourselves remains, because we cannot know whether we do not possess a nature ordered and disposed to err (_supra_, p. 226).[170] The form is rather a mistaken one, and it only generally expresses the opposition in which self-consciousness stands to the consciousness of what is different, of the objective; and we have to deal with the unity of both—the question being whether what is in thought likewise possesses objectivity. This unity rests in God, or is God Himself. I shall put these assertions in the manner of Descartes: “Amongst these various conceptions possessed by us there likewise is the conception of a supremely intelligent, powerful, and absolutely perfect Being; and this is the most excellent of all conceptions.” This all-embracing universal conception has therefore this distinguishing feature, that in its case the uncertainty respecting Being which appears in the other conceptions, finds no place. It has the characteristic that “In it we do not recognize existence as something merely possible and accidental, as we do the conceptions of other things which we perceive clearly, but as a really essential and eternal determination. For instance, as mind perceives that in the conception of a triangle it is implied that the three angles are equal to two right angles, the triangle has them; and in the same way from the fact that mind perceives existence to be necessarily and eternally implied in the Notion of the most perfect reality, it is forced to conclude that the most perfect reality exists.”[171] For to perfection there likewise pertains the determination of existence, since the conception of a non-existent is less perfect.
Thus we there have the unity of thought and Being, and the ontological proof of the existence of God; this we met with earlier (p. 63, _seq._) in dealing with Anselm.
The proof of the existence of God from the Idea of Him is in this wise: In this Notion existence is implied; and therefore it is true. Descartes proceeds further in the same direction, in so far as after the manner of empirical axioms he sets forth: (α) “There are different degrees of reality or entity, for the substance has more reality than the accident or the mode, and infinite substance has more than finite.” (β) “In the Notion of a thing existence is implied, either the merely potential or the necessary,” _i.e._ in the ‘I’ there is Being as the immediate certainty of an other-being, of the not-I opposed to the I. (γ) “No thing or no perfection of a thing which really exists _actu_ can have the Nothing as original cause of its existence. For if anything could be predicated of nothing, thought could equally well be predicated of it, and I would thus say that I am nothing because I think.” Descartes here arrives at a dividing line, at an unknown relationship; the Notion of cause is reached, and this is a thought indeed, but a determinate thought. Spinoza says in his explanation, “That the conceptions contain more or less reality, and those moments have just as much evidence as thought itself, because they not only say that we think, but how we think.” These determinate modes as differences in the simplicity of thought, had, however, to be demonstrated. Spinoza adds to this step in advance that “The degrees of reality which we perceive in ideas are not in the ideas in as far as they are considered merely as kinds of thought, but in so far as the one represents a substance and the other a mere mode of substance, or, in a word, in so far as they are considered as conceptions of things.” (δ) “The objective reality of Notions” (_i.e._, the entity of what is represented in so far as it is in the Notion), “demands a first cause in which the same reality is contained not merely objectively” (that is to say in the Notion), “but likewise formally or even _eminenter_—formally, that is perfectly likewise: _eminenter_, more perfectly. For there must at least be as much in the cause as in the effect.” (ε) “The existence of God is known immediately”—_a priori_—“from the contemplation of His nature. To say that anything is contained in the nature or in the Notion of a thing is tantamount to saying that it is true: existence is directly contained in the Notion of God. Hence it is quite true to say of Him that existence pertains of necessity to Him. There is implied in the Notion of every particular thing either a possible or a necessary existence—a necessary existence in the Notion of God, _i.e._ of the absolutely perfect Being, for else He would be conceived as imperfect.”[172] Descartes likewise argues after this manner: “Problem: to prove _a posteriori_ from the mere Notion within us the existence of God. The objective reality of a Notion demands a cause in which the same reality is not merely contained objectively” (as in the finite), “but formally” (freely, purely for itself, outside of us) “or _eminenter_” (as original). (Axiom δ.) “We now have a Notion of God, but His objective reality is neither formally nor _eminenter_ contained within us, and it can thus be only in God Himself.”[173] Consequently we see that with Descartes this Idea is an hypothesis. Now we should say we find this highest Idea in us. If we then ask whether this Idea exists, why, this is the Idea, that existence is asserted with it. To say that it is only a conception is to contradict the meaning of this conception. But here it is unsatisfactory to find that the conception is introduced thus: ‘We have this conception,’ and to find that it consequently appears like an hypothesis. In such a case it is not proved of this content in itself that it determines itself into this unity of thought and Being. In the form of God no other conception is thus here given than that contained in _Cogito, ergo sum_, wherein Being and thought are inseparably bound up—though now in the form of a conception which I possess within me.
The whole content of this conception, the Almighty, All-wise, &c., are predicates which do not make their appearance until later; the content is simply the content of the Idea bound up with existence. Hence we see these determinations following one another in an empirical manner, and not philosophically proved—thus giving us an example of how in _a priori_ metaphysics generally hypotheses of conceptions are brought in, and these become objects of thought, just as happens in empiricism with investigations, observations, and experiences.
Descartes then proceeds: “Mind is the more convinced of this when it notices that it discovers within itself the conception of no other thing wherein existence is necessarily implied. From this it will perceive that that idea of highest reality is not imagined by it, it is not chimerical, but a true and unalterable fact which cannot do otherwise than exist, seeing that existence is necessarily involved in it. Our prejudices hinder us from apprehending this with ease, for we are accustomed to distinguish in all other things the essence” (the Notion) “from the existence.” Respecting the assertion that thought is not inseparable from existence, the common way of talking is as follows: ‘If what men think really existed, things would be different.’ But in saying this men do not take into account that what is spoken of in this way is always a particular content, and that in it the essential nature of the finality of things simply signifies the fact that Notion and Being are separable.
But how can one argue from finite things to the infinite? “This Notion,” Descartes continues, “is furthermore not made by us.” It is now declared to be an eternal truth which is revealed in us. “We do not find in ourselves the perfections which are contained in this conception. Thus we are certain that a first cause in which is all perfection, _i.e._ God as really existent, has given them to us; for it is certain to us that from nothing, nothing arises” (according to Boehme God derived the material of the world from Himself), “and what is perfect cannot be the effect of anything imperfect. From Him we must thus in true science deduce all created things.”[174] With the proof of the existence of God the validity of and evidence for all truth in its origin is immediately established. God as First Cause is Being-for-self, the reality which is not merely entity or existence in thought. An existence such as this first cause (which is not what we know as a thing) rests in the Notion of the not-I, not of each determinate thing—since these as determinate are negations—but only in the Notion of pure existence or the perfect cause.
It is the cause of the truth of ideas, for the aspect that it represents is that of their Being.
d. Fourthly, Descartes goes on to assert: “We must believe what is revealed to us by God, though we cannot understand it. It is not to be wondered at, since we are finite, that there is in God’s nature as inconceivably infinite, what passes our comprehension.” This represents the entrance of a very ordinary conception. Boehme on the other hand says (_supra_, p. 212): ‘The mystery of the Trinity is ever born within us.’
Descartes, however, concludes: “Hence we must not trouble ourselves with investigations respecting the infinite; for seeing that we are finite, it is absurd for us to say anything about it.”[175] This matter we shall not, however, enter upon at present.
“Now the first attribute of God is that He is true and the Giver of all light; it is hence quite contrary to His nature to deceive us. Hence the light of nature or the power of acquiring knowledge given us by God can affect no object which is not really true in as far as it is affected by it” (the power of acquiring knowledge) “_i.e._ as it is perceived clearly and distinctly.” We ascribe truth to God. From this Descartes goes on to infer the universal bond which exists between absolute knowledge and the objectivity of what we thus know. Knowledge has objects, has a content which is known; we call this connection truth. The truth of God is just this unity of what is thought by the subject or clearly perceived, and external reality or existence. “Thereby an end is put to doubt, as if it could be the case that what appears quite evident to us should not be really true. We can thus no longer have any suspicion of mathematical truths. Likewise if we give heed to what we distinguish by our senses in waking or in sleeping, clearly and distinctly, it is easy to recognize in each thing what in it is true.” By saying that what is rightly and clearly thought likewise is, Descartes maintains that man comes to know by means of thought what in fact is in things; the sources of errors lie on the other hand in the finitude of our nature. “It is certain, because of God’s truth, that the faculty of perceiving and that of assenting through the will, if it extends no further than to that which is clearly perceived, cannot lead to error. Even if this cannot be in any way proved, it is by nature so established in all things, that as often as we clearly perceive anything, we assent to it from ourselves and can in no wise doubt that it is true.”[176] All this is set forth very plausibly, but it is still indeterminate, formal, and shallow; we only have the assertion made to us that this is so. Descartes’ method is the method of the clear understanding merely.
Certainty with him takes the first place; from it no content is deduced of necessity, no content generally, and still less its objectivity as distinguished from the inward subjectivity of the ‘I.’ At one time we have the opposition of subjective knowledge and actuality, and at another their inseparable union. In the first case the necessity of mediating them enters in, and the truth of God is asserted to be this mediating power. It consists in this, that His Notion contains reality immediately in itself. The proof of this unity then rests solely upon the fact of its being said that we find within us the idea of complete perfection; thus this conception here appears simply as one found ready to hand. With this is compared the mere conception of God which contains no existence within it, and it is found that without existence it would be imperfect. This unity of God Himself, of His Idea, with His existence, is undoubtedly the Truth; in this we find the ground for holding as true what is for us just as certain as the truth of ourselves. As Descartes proceeds further we thus find that in reality everything has truth for him only in so far as it is really an object of thought, a universal. This truth of God has been, as we shall see, expressed even more clearly and in a more concise way by a disciple of Descartes, if one may venture to call him so—I mean Malebranche (who might really be dealt with here),[177] in his _Recherche de la vérité_.
The first of the fundamental determinations of the Cartesian metaphysics is from the certainty of oneself to arrive at the truth, to recognize Being in the Notion of thought. But because in the thought “I think,” I am an individual, thought comes before my mind as subjective; Being is hence not demonstrated in the Notion of thought itself, for what advance has been made is merely in the direction of separation generally. In the second place the negative of Being likewise comes before self-consciousness, and this negative, united with the positive I, is so to speak implicitly united in a third, in God. God, who before this was a non-contradictory potentiality, now takes objective form to self-consciousness, He is all reality in so far as it is positive, _i.e._ as it is Being, unity of thought and Being, the highest perfection of existence; it is just in the negative, in the Notion of this, in its being an object of thought, that Being is contained. An objection to this identity is now old—Kant urged it likewise—that from the Notion of the most perfect existence more does not follow than that _in_ thought existence here and now and the most perfect essence are conjoined, but not _outside_ of thought. But the very Notion of present existence is this negative of self-consciousness, not out of thought,—but the thought of the ‘out of thought.’
2. Descartes accepts Being in the entirely positive sense, and has not the conception of its being the negative of self-consciousness: but simple Being, set forth as the negative of self-consciousness, is extension. Descartes thus separates extension from God, remains constant to this separation, unites the universe, matter, with God in such a way as to make Him its creator and first cause: and he has the true perception that conservation is a continuous creation, in so far as creation as activity is asserted to be separated. Descartes does not, however, trace extension in a true method back to thought; matter, extended substances, stand over against the thinking substances which are simple; in as far as the universe is created by God, it could not be as perfect as its cause. As a matter of fact the effect is less perfect than the cause, since it is that which is posited, if we are to remain at the conception of cause pertaining to the understanding. Hence according to Descartes extension is the less perfect. But as imperfect the extended substances cannot exist and subsist through themselves or their Notion; they thus require every moment the assistance of God for their maintenance, and without this they would in a moment sink back into nothing. Preservation is, however, unceasing reproduction.[178] Descartes now proceeds to further particulars, and expresses himself as follows: “We consider what comes under consciousness either as things or their qualities, or as eternal truths which have no existence outside our thought”—which do not belong to this or that time, to this or that place. He calls those last something inborn within us, something not made by us or merely felt,[179] but the eternal Notion of mind itself and the eternal determinations of its freedom, of itself as itself. From this point the conception that ideas are inborn (_innatæ ideæ_) hence proceeds; this is the question over which Locke and Leibnitz dispute. The expression “eternal truths” is current even in these modern times, and it signifies the universal determinations and relations which exist entirely on their own account. The word ‘inborn’ is however a clumsy and stupid expression, because the conception of physical birth thereby indicated, does not apply to mind. To Descartes inborn ideas are not universal, as they are to Plato and his successors, but that which has evidence, immediate certainty, an immediate multiplicity founded in thought itself—manifold conceptions in the form of a Being, resembling what Cicero calls natural feelings implanted in the heart. We would rather say that such is implied in the nature and essence of our mind and spirit.
Mind is active and conducts itself in its activity in a determinate manner; but this activity has no other ground than its freedom. Yet if this is the case more is required than merely to say so; it must be deduced as a necessary product of our mind. We have such ideas, for instance, in the logical laws: “From nothing comes nothing,” “A thing cannot both be and not be,”[180] as also in moral principles. These are facts of consciousness which Descartes however soon passes from again; they are only present in thought as subjective, and he has thus not yet inquired respecting their content.
As regards things, on which Descartes now directs his attention, the other side to these eternal verities, the universal determinations of things are substance, permanence, order, &c.[181] He then gives definitions of these thoughts, just as Aristotle draws up a list of the categories. But although Descartes laid it down formerly as essential that no hypotheses must be made, yet now he takes the conceptions, and passes on to them as something found within our consciousness. He defines substance thus: “By substance I understand none other than a thing (_rem_) which requires no other something for existence; and there is only one thing, namely God, which can be regarded as such a substance requiring no other thing.” This is what Spinoza says; we may say that it is likewise the true definition, the unity of Notion and reality: “All other” (things) “can only exist by means of a concurrence (_concursus_) of God”; what we still call substance outside of God thus does not exist for itself, does not have its existence in the Notion itself. That is then called the system of assistance (_systema assistentiæ_) which is, however, transcendental. God is the absolute uniter of Notion and actuality; other things, finite things which have a limit and stand in dependence, require something else. “Hence if we likewise call other things substances, this expression is not applicable both to them and to God _univoce_, as is said in the schools; that is to say no definite significance can be given to this word which would equally apply both to God and to the creatures.”[182] “But I do not recognize more than two sorts of things; the one is that of thinking things, and the other that of things which relate to what is extended.” Thought, the Notion, the spiritual, the self-conscious, is what is at home with itself, and its opposite is contained in what is extended, spatial, separated, not at home with itself nor free.
This is the real distinction (_distinctio realis_) of substances: “The one substance can be clearly and definitely comprehended without the other. But the corporeal and the thinking and creating substance can be comprehended under this common notion, for the reason that they are things which require God’s support alone in order to exist.” They are universal; other finite things require other things as conditions essential to their existence. But extended substance, the kingdom of nature, and spiritual substance, do not require one another.[183] They may be called substances, because each of them constitutes an entire range or sphere, an independent totality. But because, Spinoza concluded, each side, the kingdom of thought as well as nature, is one complete system within itself, they are likewise in themselves, that is absolutely, identical as God, the absolute substance; for thinking spirit this implicit is thus God, or their differences are ideal.
Descartes proceeds from the Notion of God to what is created, to thought and extension, and from this to the particular. “Now substances have several attributes without which they cannot be thought”—that signifies their determinateness—“but each has something peculiar to itself which constitutes its nature and essence”—a simple universal determinateness—“and to which the others all relate. Thus thought constitutes the absolute attribute of mind,” thought is its quality; “extension is” the essential determination of corporeality, and this alone is “the true nature of body. What remains are merely secondary qualities, modes, like figure and movement in what is extended, imagination, feeling and will in thinking; they may be taken away or thought away. God is the uncreated, thinking substance.”[184] Descartes here passes to what is individual, and because he follows up extension he arrives at matter, rest, movement. One of Descartes’ main points is that matter, extension, corporeality, are quite the same thing for thought; according to him the nature of body is fulfilled in its extension, and this should be accepted as the only essential fact respecting the corporeal world. We say that body offers resistance, has smell, taste, colour, transparency, hardness, &c., since without these we can have no body. All these further determinations respecting what is extended, such as size, rest, movement, and inertia, are, however, merely sensuous, and this Descartes showed, as it had long before this been shown by the Sceptics. Undoubtedly that is the abstract Notion or pure essence, but to body or to pure existence, there likewise of necessity pertains negativity or diversity. By means of the following illustration Descartes showed that with the exception of extension, all corporeal determinations may be annihilated, and that none can be absolutely predicated. We draw conclusions respecting the solidity and hardness of matter from the resistance which a body offers to our disturbance, and by means of which it seeks to hold its place. Now if we admit that matter as we touch it always gives way to us like space, we should have no reason for ascribing to it solidity. Smell, colour, taste, are in the same way sensuous qualities merely; but what we clearly perceive is alone true. If a body is ground into small parts, it gives way, and yet it does not lose its nature; resistance is thus not essential.[185] This not-being-for-itself is however a quantitatively slighter resistance only; the resistance always remains. But Descartes desires only to think; now he does not think resistance, colour, &c., but apprehends them by the senses only. Hence he says that all this must be led back to extension as being special modifications of the same. It is undoubtedly to the credit of Descartes that he only accepts as true what is thought; but the abrogation of these sensuous qualities simply represents the negative movement of thought: the essence of body is conditioned through this thought, that is, it is not true essence.
Descartes now makes his way from the Notion of extension to the laws of motion, as the universal knowledge of the corporeal in its implicitude; he shows (α) that there is no vacuum, for that would be an extension