Indeed, by the very fact that a being is supposed capable of thinking, it is supposed able to say to itself, I think. This act is eminently experimental, and it needs only to be united with general truths in a common consciousness, to enable the isolated being to rise above itself, and create for itself a positive science, by which to pass from the world of ideas to that of facts. The instability of its thoughts, and the permanence of the being that experiences them, offer to it a practical case in which the general ideas of substance and accident are particularized. The successive appearance and disappearance of its own conceptions will show to it the ideas of being and of not-being realized; the recollection of the time when its own operations commenced, beyond which the memory of its existence does not extend, will enable it to know the contingency of his own being; and this fact, combined with the general principles which express the relations between contingent and necessary beings, will suggest to the thought that there must be another that communicated to it its existence.
CHAPTER XV.
ILLUSTRATIONS OF THE VALUE OF GENERAL CONCEPTIONS
96. However vague the ideas an isolated being would form of objects distinct from itself, they will never be so vague as not to refer to a real thing. The mind may not know the nature of this reality, but it knows for certain that it exists. A man blind from his birth can form no clear idea of colors, nor of the sensation of seeing; but is he therefore ignorant that sensation exists, and that the words, color, seeing, and others which refer to sight, have a positive and determinate object? Certainly not. The blind man does not know in what these things, of which he hears, consist, but he knows that they are something; those of his conceptions that refer to them may be called imperfect, but they are not vain; the words by which he expresses them, have for him a positive, although incomplete meaning.
97. There is a great difference between incomplete and indeterminate conceptions; the former may refer to a positive thing, although imperfectly known; the latter include nothing but a relation of ideas, meaning nothing in the order of facts. We will render this difference more apparent by explaining the example of the preceding paragraph.
A man blind from his birth has no intuition of colors, nor of any thing that refers to the sense of sight; but he is sure that there exist external facts which correspond to an internal affection called seeing. This idea is incomplete, but it has a determinate object. The words of those who possess the sense of sight reveal to him its existence; he knows not, what it is, but, that it is; in other words, he does not know its essence, but its existence. Let us now suppose the possibility of an order of sensations different from ours, and in nowise resembling those which we experience, to be called in question. The conception referred to the new sensations would not only be incomplete, but would have no relation to any real object. The general idea, then, of affection of a sensitive being, will be all that our mind will have; but it will know nothing of its existence, and can form only mere conjectures as to the conditions of its possibility. This example illustrates our idea. We find in the man blind from his birth, who hears of what pertains to the sense of sight, an incomplete conception, but one to which the existence of a series of facts, known to his mind, corresponds. But in ourselves, if we reflect upon a kind of sensations different from our own, we find conceptions, having, indeed, a general object, but of whose realization we know nothing.
98. Thus is it explained how our mind, without having intuition of a thing, can, nevertheless, know it, and be perfectly certain of its existence. We have here demonstrated that conceptions may, although they do not refer to a sensible intuition, have a value, not only in the order of ideas, but also in that of facts.
99. In order to prove the sterility of all conception beyond sensible intuition, Kant adduces one reason, which is, that we cannot define the categories and the principles which flow from them without referring to the objects of sensibility. This is no proof at all; for, in the first place, the impossibility of a definition does not always arise from the fact that the conception to be defined is empty; but it very frequently results from the conception being simple, and consequently not susceptible of a division into parts that may be expressed by words. How will he define the idea of being? No matter how he attempts to define it, the thing to be defined will enter into the definition: the words, thing, reality, existence, all signify being.
It is very natural, since sensible intuition is the basis of our relations with the external world, and consequently with our fellow-men, that when we purpose to express any relation whatever, we should call to our aid sensible applications; but we are not thence to infer that there is not in our mind, independently of them, a real truth contained in the conception which we wish to explain.
100. This capacity of knowing objects under general ideas, is a characteristic property of our mind, and we cannot, in our inability to penetrate to the essence of things, think without this indispensable auxiliary. In the ordinary course of human affairs, it often happens that we need to know the existence of a thing and of some of its attributes, but do not require a perfect knowledge of it. In such cases, general ideas, aided by some data of experience, put us in mediate communication with the object not presented to our intuition. But why cannot the same thing be verified with respect to non-sensible beings, which alone are the object of intellectual intuitions? I know not what exception can be taken to these observations, founded as they are upon observation of internal phenomena, and confirmed by common sense.
CHAPTER XVI
VALUE OF PRINCIPLES, INDEPENDENTLY OF SENSIBLE INTUITION
101. The principle of contradiction, indispensable condition of all certainty, of all truth, and without which the external world, and intelligence itself, would become a chaos, offers us a good example of the intrinsic value of purely intellectual conceptions independent of sensible intuition.
No determinate idea is united to the conception of being when we affirm the impossibility of a thing being and not-being at the same time, or the exclusion of not-being by being; and so far we absolutely abstract all sensible intuition. Whatever be its object, whatever its nature and the relations of its existence; be it corporeal or incorporeal, composite or simple, accident or substance, contingent or necessary, finite or infinite, always will it be found true that being excludes not-being; the absolute incompatibility of these two extremes will always be verified, so that the affirmation of the one is always, in all cases, and under all imaginable suppositions, the negation of the other.
This being so, to limit the value of these conceptions to sensible intuition, would be to destroy the principle of contradiction. The limitation of the principle is equivalent to its nullification. Its absolute universality is closely allied to its absolute necessity; if it be curtailed, it is made contingent; for, if the principle of contradiction may fail us in one instance, it fails us in all. To admit the possibility of what is absurd, is to deny its absurdity. If the contradiction of being and not-being does not exist in every supposition, it exists in no supposition.
102. The difficulty is to know how the transition from the principle of contradiction to real truths, is made; because not affirming any thing determinate in it, but solely the repugnance of yes to no, and of no to yes, we assert that it would be impossible to affirm either one of these extremes without denying the other; and as on the other hand, it is impossible, if we confine ourselves to the principle of contradiction, for it to include any thing more than the most general relation between two general ideas, we conclude that it is of itself alone, perfectly sterile and unable to conduct us to any positive result. This is all true; but it contradicts in no point what we have said concerning the intrinsic value of general conceptions.
We have remarked that truths of the purely ideal order have none but a hypothetical value, and that in order to produce a positive science, they require facts to which they may apply. We have also remarked, that experience furnishes these facts, and that every thinking being possesses one at least, consciousness of itself. Every thinking being will therefore, provided it discover in its own consciousness facts to which it may apply it, make a positive use of the principle of contradiction.
103. Even