176. This passage shows very clearly Descartes' ideas; he destroyed every thing by doubt, excepting one thing which defied all his efforts, the consciousness of himself; and this consciousness he took for the basis, on which, with full certainty, he might build anew the edifice of science. Locke and Condillac did nothing else; they followed, indeed, a different path, but their point of departure was at all times the same. Locke says: "First, I shall inquire into the original of those ideas, notions, or whatever else you please to call them, which a man observes, and is conscious to himself he has in his mind; and the ways whereby the understanding comes to be furnished by them."13 "Since the mind, in all its thoughts and reasonings, hath no other immediate object but its own ideas, which it alone does or can contemplate, it is evident that our knowledge is only conversant about them."14 "Whether, to speak metaphorically," says Condillac, "we ascend even to the heavens, or descend into the abysses, we do not go out of ourselves, and it is always our own thought that we perceive."15
177. All ideological labors commence then by establishing the fact of consciousness of our ideas; and it cannot be otherwise with respect to their certainty. Man, although he overthrow and destroy every thing, still encounters himself, the one who overthrows and destroys every thing. When he has gone so far as to doubt the existence of God, the world, his fellow-beings, his own body, he still, in the midst of this immense solitude, encounters himself. The effort to conceal himself from his own eyes serves only to render him more visible: he is a spirit to be killed by no blow, and rays of light flow from every wound inflicted on him. If he doubts that he feels, he at least feels that he doubts; if he doubts of this doubt, he feels that he doubts of doubt itself; thus, in doubting of direct acts, he enters into an interminable series of reflex acts, necessarily linked one with the other, and unrolled to the internal view like folds of a scarf which has no end.(18)
178. We have already seen that Descartes' principle, considered as an enthymema, cannot aspire to be fundamental. In every argument there are premises and a consequence; and to be conclusive, the premises must be true, and the consequence legitimate. To say that an argument may be a fundamental principle, is a manifest contradiction.
But if we take Descartes' principle in the sense above explained, that is, not as an argument but as the declaration of a fact, the contradiction ceases, and it is a question, worthy to be examined, whether it merits the title of fundamental principle or not, and in what sense. We have already somewhat illustrated this matter, but not yet sufficiently cleared it up; we have made some preliminary remarks in order to show the state of the question, but have not yet completely solved it.
179. The proposition, I think, as we have remarked, expresses something more than merely thought, strictly so called: it embraces acts of the will, sentiments, sensations, acts, and expressions of all kinds which are realized within us; it includes all phenomena immediately present to our mind, and attested by consciousness.
Nothing that distinguishes between various acts and impressions can be a fundamental principle: such a distinction supposes analysis, and analysis requires reflection. We do not reflect without rules and objects already known; consequently, to admit classifications in the first principle, is to divest it of its character and to contradict ourselves.
180. We must not confound what is expressed by the proposition I think with the proposition itself. The thing itself and the form are here very different: the nature of the form may make us conceive ambiguous ideas of the thing itself: the thing itself is a most simple fact; the form is a logical combination, and includes very heterogeneous elements. This demands explanation.
The fact of consciousness, in itself considered, abstracts all relations; it is nothing but itself, leads to nothing but itself; it is the presence of the act or impression, or rather it is the act, the impression itself, which is present to the mind. There is no combination of ideas, no analysis of conceptions; when it comes to this latter, it leaves the territory of pure consciousness, and enters the objective regions of intellectual activity. But as language is to express the products of this activity, and as it is cast, so to say, not in the mould of consciousness, but in that of the intellect, it is impossible for us to speak without some logical or ideal combination. Were we seeking an expression of pure consciousness, unmixed with intellectual elements, we should seek it not in language, but in the natural sign of grief, joy, or some other passion; in this alone is it expressed spontaneously and uncombined with foreign elements, that something passes in our mind, that we are conscious of something; but the instant that we speak, we express something more than pure consciousness: the external world indicates the internal, the product of intellectual activity, its conception; and this involves a subject and an object, and therefore pertains to an order far superior to that of consciousness.
181. To demonstrate the truth of what we have just said, let us examine the expression, I think. This is a true proposition, and it may, without being in the least changed, be presented under a strictly logical form, I am thinking. Here we have a subject, a predicate, and a copula. The subject is I; that is to say, we at once find the idea of a being, the subject of acts and impressions, the possessor of an activity expressed in the predicate. This I is then presented to us as something far superior to the order of pure consciousness; it is nothing less than the idea of substance. We will analyze more at length what is contained under it.
We have, in the first place, the idea of unity: the I has no meaning, if it do not denote that something is one and identical, notwithstanding the plurality and diversity realized in it. The experimental unity of consciousness draws with it, as a rigid consequence, the unity of the being possessing it. This being is the subject; and in it are realized the variations without which it would be impossible to say I. We hold then that in so simple an expression the ideas of unity and its relation to plurality, of substance and its relations to accidents, are contained; that is, the idea of the soul, although expressive of a most simple unity, is, under the logical aspect, composite, and contains many things pertaining to the ideal order, and not to be found in pure consciousness. The idea of the soul, strictly speaking, although in a certain sense common to all men, is in itself highly philosophical, for it involves a combination of elements belonging to the intellectual order.
182. The predicate thinking is the expression of a general idea, comprehending not only all thought, but also all phenomena which immediately affect the mind. These phenomena, considered in what they have in common, under the general idea of present to the mind, are expressed in the word thinking.
The relation of the predicate with the subject, or the agreement of thinking with the soul, also expresses an analysis worthy of attention. We at once detect a decomposition of the conception of the soul into two ideas; that of the subject of various modifications, and that of thinking. Otherwise the proposition has no meaning, or rather its expression becomes impossible. The idea of subject involves the ideas of unity and substance, and that of thinking involves the idea of activity, or of passivity, so to speak, accompanied by consciousness.
183. To render the proposition possible, we must suppose the decomposition of the ideas to commence at some point, that is, either in the idea of the soul we find that of thinking, or in that of thinking we find that of the soul. Fixing ourselves in the soul, and abstracting thinking, we meet with the idea of subject, or of substance in general; and there, however much we cavil, we shall never find the idea of thinking. The soul in itself is not manifested to us; we know it by thought; in thought therefore we must fix the point of departure, not in the soul; wherefore in the above proposition, what is primitively known is rather the predicate than the subject; and of the two conceptions, that of subject has rather the character of a thing contained, than of a thing containing.
The soul by itself, so to speak, springs up with the presence of thought. If the intellectual activity is concentrated in search of its first basis, it finds it, not in the pure subject, but in its acts, that is, in its thoughts. These last are then the first object of reflective intellectual activity, its first element of combination, its first datum for the solution of the problem. Fixing its sight on this element, it discovers a unity in the midst of plurality, a being that remains the same through the ebb and flow of the phenomena of consciousness; and this identity is incontestably asserted by consciousness itself. The idea of the soul then is taken from that of thought, and consequently the subject springs from the predicate, rather than the predicate from the subject.
184. The thought from which we derive the idea of the soul is not thought in general, but thought realized, existing in ourselves. But this reality is sterile unless offered to the mind under a general idea; for it is evident that the soul does not come from one single act, since it is unity, the subject of plurality. To arrive at the idea of the soul we require unity of consciousness, and this we know only as we have experienced it, that is, so far as we perceive the relation of the one to the multiple, of a subject to its modifications.
Such elaboration is necessary to the production of so simple an expression as I think; and here we see how much reason there is to distinguish between the thing itself and the form, and how inconsiderately they act who confound things so different. Thus, from want of due analysis, they take in philosophy immense strides from one order to another, confound ideas and entangle matters.
185. To completely illustrate this matter, we will examine the relations of existence to thought; a very easy examination, if we bear in mind the observation just made.
It is certain that we conceive existence before thought: nothing can think without existing: existence is an indispensable condition to thought: to think and not to exist is a manifest contradiction. But what is first offered to our mind is not existence, but thought, and this not in the abstract, but determinate, experimental, or as the expression now is, empyrical. The idea of existence is general, includes all beings, and consciousness cannot commence with it. At one time we obtain this idea by abstraction; at another, it is a form pre-existing in our mind, not the first that occurs to us, or to speak more exactly, not the last point to be attained when we follow back the thread of our cognitions in order to discover their starting-point. This consciousness, when made objective, and when the conception which it offers is analyzed, presents to us the idea of existence as contained in itself.
Hence we infer that the therefore I exist is not, strictly speaking, a consequence of the I think, but the intuition of the idea of existence in that of thought. There are here two propositions per se notæ, as the scholastics say: the one general, the thinking is existing; the other particular, I thinking am existing. The first belongs to the purely ideal order, and is intrinsically evident, independently of all particular consciousness; the second participates of the two orders, the real and the ideal; the real, in so far as it includes the particular fact of consciousness; the ideal, in so far as it includes a combination of the general idea of existence with the particular fact; since thus only is the union of the predicate with the subject conceivable.
186. It will now be very easy to solve all the questions discussed in the schools.
First question. Does the principle I think depend on another? We answer with a distinction. If by this principle is meant the simple fact of consciousness, it evidently does not. For our understanding there is nothing prior to ourselves; whatever we know so far forth as known by us, supposes our consciousness; if we suppress it, we destroy every thing, and although we attempt to destroy every thing, it still remains indestructible, since it depends on nothing, presupposes nothing.
If by the principle I think is meant a proposition, it can only have proceeded from reasoning or analysis, and so cannot be the fundamental principle of our cognitions.
187. Second question. When the other principles are wanting, is this one also wanting? We must apply the same distinction here: as a simple fact? No! as a proposition? Yes! Deny every thing, even the principle of contradiction, and consciousness still subsists; but deny the principle of contradiction, and every proposition is destroyed, every combination becomes absurd: analysis, and the relation of the predicate with the subject, are unmeaning words.
188. Third question. Admitting the principle I think, can he who denies the others be reduced at least indirectly to truth? We again distinguish: you speak of reducing him either by reasoning or by observation; that is, either you wish to convince him by arguments, or else to turn his attention to himself, as is done with a man distracted, or one suffering mental derangement. The second is possible, but not the first. Whoever denies all principles, that of contradiction included, makes all argument impossible; in vain then will you reason with him. Let us see.
You think, one may say to him, at least you so assert, when you admit the principle I think. True. Then you must also admit the principle of contradiction. Why so? Because otherwise you could think and not think at the same time. Very well. But then you destroy your own thought. How? Is it not true that you think? Certainly. According to yourself it is possible that at the same time you do not think. I agree with you. Therefore, you destroy your thought; for if you do not think, the I think is destroyed, and, as all this is simultaneous, you destroy your own thought.
Not at all. What I object to in your system is that you suppose true the very thing which I deny, and so fall into the sophism named by logicians petitio principii. By the very fact of my denying the principle of contradiction, I deny that not-being destroys being, and that being destroys not-being; consequently, I do not admit that the I do not think destroys the I think. When you argue against me in this way, you suppose the very point in question, and attack me with principles which I do not admit. In your system, in which being destroys not-being, and vice versa, it is certain that to think, and not think, are incompatible; but on my principles, it is a very simple thing; since, according to them, it is not impossible for the same thing to be and not be at the same time, when I do not think, I do not cease to think. This is indeed absurd, but not illogical; deny the principle, and the deduction is necessary. And if it be said that in such a case he cannot reason, as he just has reasoned, he may reply that neither can his adversaries reason; or, if you choose, he sees no difficulty in their both reasoning and not reasoning.
Observation is the only means of bringing back one who has thus strayed away; such a one has departed from reason, and cannot be brought back to it by means of reason. Observations directed to him must be more of a call, a sort of alarm to arouse reason, not a combination to re-construct it: he is as a man asleep, or one in a swoon, and we must call him, and shake him, in order to arouse him; we must not dispute with him as with an adversary.(19)
189. Before examining the value of the principle of contradiction as a basis for our cognitions, it will be well to fix its true and exact sense. This renders necessary some considerations upon an opinion of Kant, advanced in his Critic of Pure Reason, when treating of the form in which the principle of contradiction has hitherto been enunciated in all schools of philosophy. The German metaphysician grants, that whatever may be the matter of our cognitions, and in whatever manner they may relate to their object, it is a general, although a purely negative, condition of all our judgments, that they should not mutually contradict each other; otherwise, even without reference to their object, they are nothing in themselves. This doctrine established, he observes that what is called the principle of contradiction is the following: "A predicate that is opposed to a subject does not belong to it;" and then goes on to say, that this is a universal, although purely negative criterion of all truth; that it moreover belongs exclusively to logic, since it is of use to pure cognitions as to cognitions in general, without relation to their object, and he declares that the contradiction makes them completely disappear. "But of this celebrated principle, although stripped of all contents, and purely formal," he continues, "there is still a formula containing a synthesis, which has inadvertently, and quite unnecessarily, been mixed up therein. It is this: It is impossible for the same thing to be and not be at the same time. Not only has the apodictic certainty (by the word impossible) been unnecessarily added, which certainty would have been of itself understood from the proposition; but the proposition is affected by the condition of time, and says, as it were: a thing = A, which is something = B, cannot at the same time be not B, but it can very well be both (B as well as not B) in succession. For example: a man who is young, cannot at the same time be old; but the same person may very well be young at one time, at another not young, that is, old. Now, the principle of contradiction, as a mere logical principle, must not at all restrict its meaning to the relations of time, and consequently, such a formula is quite opposed to its intention. The misapprehension arises simply from this: that we first separate the predicate of a thing from its conception, and afterwards unite its opposite with this predicate, which never gives a contradiction with the subject, but only with its predicate, which is synthetically joined with that subject, and that only when the first and second predicates are asserted at the same time. If I say a man who is unlearned is not learned, the condition, at the same time, must be expressed; for he who is unlearned at one time may very well be learned at another. But if I say no unlearned man is learned, the proposition is analytic, since the sign (the unlearnedness) now constitutes the conception of the subject, and then the negative proposition is evident immediately from the principle of contradiction, without it being necessary for the condition, at the same time, to be added. This is also the cause why I have so changed the formula of this principle, that the nature of an analytic proposition might be clearly expressed."16
190. The reader will not easily comprehend the meaning of this passage, not very clear of itself, unless he knows what Kant understands by analytic and synthetic propositions. We will explain this. In all affirmative judgments, the relation of a predicate to a subject is possible in two manners: either the predicate belongs to the subject as contained in it, or is completely extraneous to it although joined with it. In the former case, the judgment is analytic; in the latter, it is synthetic. Analytic affirmative judgments are those in which the union of the predicate with the subject is conceived by identity: those are called synthetic in which this union is conceived without identity. Kant illustrates his idea by the following examples: "When I say all bodies are extended, I express an analytic judgment; for I need not go out of the conception of body in order to find that of extension, which I connect with it, but I have only to analyze the conception of body, that is, to become conscious of the diversity which I always think in this conception, in order to find the predicate. It is, therefore, an analytic judgment. But when I say, all bodies are heavy, the predicate heaviness is by no means included in my conception of the subject, that is, of body in general. It is a conception added to the conception of body. The addition in this way of the predicate to the subject gives a synthetic judgment."17
It is easy to see the reason of the new nomenclature employed by the German philosopher. He calls those judgments analytical, in which it suffices to decompose the subject to find therein the predicate, without the necessity of adding any thing not already thought, at least obscurely, in the very conception of the subject; and he calls synthetic those in which it is necessary to add something to the conception of subject, since the predicate is not found in this conception however much we decompose it.
191. This division of judgment, into analytic and synthetic, is much used in modern philosophy, above all among the Germans; certainly there are some who may imagine this to be a discovery made by the author of the Critic of Pure Reason; and the very novelty of the name may give occasion to equivocation. Yet, in all the scholastic writers who lie forgotten, and covered with dust, in the recesses of libraries, we find analytic and synthetic judgments, though not under these names. They said there were two kinds of judgments; some, in which the predicate was contained in the idea of subject, and others, in which it was not. They called the propositions which expressed judgments of the former class, per se notæ, or known by themselves, because, the meaning of the terms being understood, the predicate was seen to be contained in the idea, or the conception of the subject. They also called them first principles, and the perception of them, intelligence, intellectus, to distinguish them from reason, which is conversant about the cognitions of mediate evidence, or ratiocination.
See if the following texts of St. Thomas leave any thing to be desired in clearness or precision: "A proposition is known by itself, per se notæ, when the predicate is contained in the subject, as; man is an animal; for animal is of the essence of man. If, then, it is known to all, what the subject and the predicate are, that proposition will be known by itself to all, as is seen in the first principles of demonstration, which are certain, common things, not unknown to any one, as being and not-being, the whole, the part, and others similar."18
"Any proposition the predicate of which is of the essence of the subject, is known by itself, although such a proposition is not known by itself for any one who is ignorant of the definition of the subject. Thus this proposition, man is rational, is by its nature known by itself, because whoever says man, says rational."19
192. By these, and many other examples, which it would be easy to adduce, it is seen that the distinction between analytic and synthetic judgments was common in the schools centuries before Kant flourished. Analytic judgments were all those formed by immediate evidence; and synthetic, those resulting from mediate evidence, whether of the purely ideal order, or in some sense depending on experience. It was well known that there were conceptions of the subject, in which the predicate was thought, at least confusedly; and thus union, or identity, was explained by saying that the propositions, in which it was found, were per se notæ ex terminis. In analytic judgments, the predicate is in the subject; nothing is added, according to Kant, it is only unfolded. Whoever says man says rational, are the words of St. Thomas: the idea is the same as that of the German philosopher.
193. But let us see if it is necessary to change the formula by which the principle of contradiction has hitherto been expressed.
The first observation of Kant refers to the word impossible, which he considers unnecessarily added, since the apodictic certainty, which we wish to express, should be contained in the proposition itself. Kant's formula of the principle is this: "a predicate which is opposed to a subject, does not belong to it." What is the meaning of the word impossible? "Possible and impossible absolutely, are said in relation to the terms. Possible, because the predicate is not opposed to the subject; impossible, because the predicate is opposed to the subject;" says St. Thomas,20 and with him agree all the schools. Therefore, impossibility is the opposition of the predicate to the subject, and to be repugnant is the same thing as to be impossible, and Kant uses the very language which he blames in others. The common formula might be expressed in this manner: "there is opposition in the same thing being and not-being at the same time," or, "being is opposed to not-being," or, "being excludes not-being," or, "every thing is equal to itself;" and Kant expresses nothing more when he says: "a predicate which is opposed to a subject does not belong to it."
194. As a universal criterion, there is more exactness in the common formula than in that of Kant. The latter restricts the principle to the relation of predicate and subject, and consequently to the purely ideal order, making it of no value for the real, unless by a sort of enlargement. This enlargement, although legitimate and easy, is not needed in the common formula: by saying being excludes not-being, we embrace the ideal and the real, and present to the mind the impossibility, not only of contradictory judgments, but also of contradictory things.
Kant admits that the principle is the condition sine qua non of the truth of our cognitions, so that we must take care not to place ourselves in contradiction with it, under pain of annihilating all cognition. Let us put this to the proof. Give a man, unacquainted with these matters, although not ignorant of what is meant by predicate and subject, these two formulas; which will appear to him the best for all uses in the external as in the internal? Certainly not that of Kant. He sees in an instant, in all its generality, that a thing cannot both be and not be at the same time; and he applies the principle to all uses as well in the real as in the ideal order. Treating of an external object, he says, this cannot both be and not be at the same time; treating of contradictory judgments, of ideas which exclude one another, he says, without any difficulty, this cannot be, because it is impossible for the same thing to be and not be at the same time. But it is not so easily and so readily seen how transition is made from the ideal to the real order, or how the purely logical ideas of predicate and subject can be used in the order of facts. The common formula, then, besides being fully as exact as that of Kant, is more simple, more intelligible, and more easy of application. Are there any qualities more desirable than these in a universal criterion, in the condition sine qua non of the truth of our cognitions?
195. We have thus far supposed Kant's formula really to express the principle of contradiction; but this supposition is far from being exact. Undoubtedly there would be a contradiction, were a predicate opposed to a subject, and yet to belong to it; and in this sense it may be said that the principle of contradiction is in some manner expressed in Kant's formula. But this is not enough; for we should then be obliged to say that every axiom expresses the principle of contradiction, since no axiom can be denied without a contradiction. The formula of the principle must directly express reciprocal exclusion, opposition between being and not-being; this is what was intended, and nothing else was ever meant by the principle of contradiction. Kant, in his new formula, does not directly express this exclusion: what he expresses is, that when the predicate is excluded from the idea of the subject, it does not belong to it. So far from expressing the principle of contradiction, it is the famous principle of the Cartesians: "whatever is contained in the clear and distinct idea of any thing may be affirmed of it with all certainty." In substance the two formulas express the same thing, and are only distinguished by these purely accidental differences: first, that Kant's formula is the more concise; second, that it is negative, and that of the Cartesians affirmative.
196. Kant says: "whatever is excluded from the clear and distinct idea of any thing, may be denied of it." A predicate which is opposed to a subject "is the same thing as that which is excluded from the idea of any thing;" "does not belong to it" is the same as "may be denied of it." And as, on the other hand, the principle of the Cartesians must be understood in both senses, the affirmative and the negative, because when they say that whatever is contained in the clear and distinct idea of any thing may be affirmed of it, they mean also that when any thing is excluded, it may be denied; it follows that Kant says the same thing as the Cartesians; and thus, in attempting to correct all the schools, he has fallen into an equivocation not of a nature to acquire him any great credit for perspicacity.
It is clear that Kant's formula implies this: the predicate contained in the idea of a subject belongs to it. This condition is equally the condition sine qua non of all analytic affirmative judgments; for these disappear if that does not belong to the subject which is contained in its idea. In this case there is not even an apparent difference between Kant's formula and that of the Cartesians; the only difference is in terms; the propositions are exactly the same. Hence we see that instead of affirming that the schools expressed themselves inaccurately in the clearest and most fundamental point of human knowledge, we ought to proceed with great circumspection; witness the originality of Kant's formula.