without the aid of general ideas and propositions, impossible. Light results from the union of one with the other; separated they afford only an abstract and vague intuition, or the contemplation of a particular truth, which, limited to a contracted sphere, can give no knowledge of beings considered under a scientific aspect.
142. We shall see when we come to treat of ideas, that our mind has two very distinct classes of them; the one supposes space, and cannot abstract it, such are all geometrical ideas: the other does not relate to space, and includes all non-geometrical ideas. These two orders of ideas are separated by an impassable abyss, if the two orders are not approximated by a simultaneous use of both. The ideal order is not complete without this approximation; and the real order of the universe is turned into a chaos, or rather disappears, if real and ideal truths are not combined, in both the geometrical and non-geometrical orders. From all geometrical ideas imaginable, considered in all their ideal purity, nothing would result for the ideal non-geometrical order, for the world of material, much less of immaterial realities; and, on the other hand, from non-geometrical ideas alone we could not get so much as the idea of a right line. This observation shows that there is for us in the ideal order no one truth, the origin of all other truths; for if we take the geometrical order, we are limited to those combinations which do not go out of it; if the non-geometrical order, we lack the idea of space, without which we lose even the possibility of conceiving the corporeal world.(14)
CHAPTER XV.
THE INDISPENSABLE CONDITION OF ALL HUMAN KNOWLEDGE.—MEANS OF PERCEIVING TRUTH.
143. We have not been able to discover, either in the real or the ideal order, a truth, the origin of all other truths to our intellect while in this life. Therefore it stands proved that transcendental science properly so called is for us a chimera. Our cognitions must, doubtless, have some resting-point, and this we shall now investigate.
For the better understanding of the subject now before us, we will recall the true state of the question. We do not seek a first principle, which of itself alone illumines or produces all truths; but we seek a truth which shall be the indispensable condition of all knowledge; for this reason, we do not call it an origin, but a resting-point. The edifice does not originate in the foundation, but rests upon it. We must consider the principle sought for as a foundation, just as in the preceding chapters, we treated of discovering a seed. These two images seed and foundation, perfectly express our ideas, and exactly trace the limits of the two questions.
144. Is there a resting-point of all science, and of all knowledge, scientific or not scientific? If there is, what is it? Are there many, or only one? Evidently there must be a resting-point. If asked the reason of an assent, we must at last come to a fact or a proposition, beyond which we cannot go; for we cannot admit the process ad infinitum. This is the point where we must of necessity stop, and consequently the resting-point of certainty.
145. Starting with a given assent, we may, perhaps, arrive at different principles, independent one of the other, all equally fundamental, as regards our mind: in this case there will be not only one, but many resting-points.
We do not believe it possible to determine a priori, whether there is unity or plurality for our intellect in this matter. That human science must be reduced to a single principle is a proposition that has been asserted, but never yet proved. Since the source of all truth, as has been shown in the preceding chapters, is not in man, it is evident that the principles, on which his knowledge is founded, must be communicated. Who shall assure us that they are not many in number, and of different orders? Nothing then in the present question can be resolved a priori, and we must descend to ideological and psychological observations.
146. Our mind acquires truth, or at least the appearance of truth; that is to say, that in one way or another, it performs those acts which we call perception and sensation. Whether the reality does or does not correspond to the acts of our soul, is at present of no consequence, is not what we now seek: we place the question on a ground accessible to the most skeptical; for even they do not deny perception and sensation; although they destroy reality, they admit appearance.
147. The means by which we perceive truth are of different orders; and this is why truths perceived correspond equally to different orders, parallel, so to speak, with the respective means of perception.
Consciousness, evidence, and intellectual instinct or common sense, are the three means; to which correspond truths of consciousness, necessary truths, and common-sense truths. These are distinct, different, and in many cases unconnected with each other; and he, who seeks to acquire complete and accurate ideas upon matters relating to the first principle of human knowledge, must mark out their limits with great care.
148. That means which we have called consciousness, or the intimate sense of that which passes within us, that which we experience, is independent of all the others. Destroy evidence, destroy intellectual instinct, yet consciousness remains. In order to feel, and to be sure that we feel, and what we feel, we need only experience. If we suppose the principle of contradiction to be doubtful, still it will not shake our certainty that we suffer when we suffer, that we rejoice when we rejoice, that we think when we think. The presence of the act, or the impression at the bottom of our soul, is intimate, immediate to us, and of irresistible efficacy to place us above all doubt. Sleeping or waking, sane or insane, the testimony of consciousness is the same; there may be an error in the object, but there can be none in the internal phenomenon. The lunatic who believes that he counts numberless bags of dollars, certainly does not count them, and in this he is deceived; yet he has in his mind the consciousness of what he does, and in this he is infallible. A man who dreams that he has fallen into the hands of robbers, is deceived as to the external object, but not as regards the act by which he believes it.
Consciousness is independent of all extrinsic testimony; its necessity is inevitable, its force irresistible in producing certainty; it is infallible in what concerns only itself; if it exist it must give testimony of itself; if it does not exist it cannot give it. In it reality and appearance are confounded; it cannot be apparent without being real; the appearance alone is already a true consciousness.
149. We include in the testimony of consciousness all that which we experience in our soul, all that which affects what some call the human me, ideas, thoughts of every class, acts of the will, sentiments, sensations; in a word, every thing of which we can say: I experience it.
150. Manifestly the truths of consciousness are rather facts to be pointed out, than combinations to be enunciated. This is not to say that they cannot be enunciated, but that in themselves they abstract all intellectual form, are simple elements, in ordering and comparing which the intellect may occupy itself, but which of themselves give no light, represent nothing, but only present what they are; that they are mere facts, beyond which we cannot go.
151. The habit of reflecting upon consciousness, and of joining purely intellectual operations with facts of simple internal experience, makes it difficult to conceive this isolation, in which every thing purely subjective is by its nature found. We endeavor to abstract reflection, but we reflect upon our very effort to abstract it. Our intellect is a fire, which, extinguished on one side, burns on the other; the very effort to extinguish it ordinarily makes it burn brighter. Hence the difficulty of distinguishing the two characters of purely subjective and purely objective, to mark the dividing line between evidence and consciousness, between the known and the experienced. Nevertheless, the separation of two such different elements may be made easy, by considering that brutes are, in their own way, conscious of what they inwardly experience; not supposing them to be mere machines, we must allow them consciousness, or the intimate presence of their sensations. Without this even sensation is inconceivable,
