This theory, moreover, is in itself so simple, that, without the dress of regular demonstrations upon which it is founded, its own evidence will sufficiently establish it. It wholly rests upon the distinction between the different forms under which truth is presented to us. It is, in its somewhat arid generality, as follows:
1st. One can perceive truth in two different ways. Sometimes one perceives it in such or such a particular circumstance. For example, in presence of two apples or two stones, and of two other similar objects placed by the side of the first, I perceive this truth with absolute certainty, viz., that these two stones and these two other stones make four stones,—which is in some sort a concrete apperception of the truth, because the truth is given to us in regard to real and determinate objects. Sometimes I also affirm in a general manner that two and two equal four, abstracting every determinate object,—which is the abstract conception of truth.
Now, of these two ways of knowing truth, which precedes in the chronological order of human knowledge? Is it not certain, may it not be avowed by every one, that the particular precedes the general, that the concrete precedes the abstract, that we begin by perceiving such or such a determinate truth, in such or such a case, at such or such a moment, in such or such a place, before conceiving a general truth, independently of every application and different circumstances of place and time?
2d. We can perceive the same truth without asking ourselves this question: Have we the ability not to admit this truth? We perceive it, then, by virtue alone of the intelligence which has been given us, and which enters spontaneously into exercise; or rather, we try to doubt the truth which we perceive, we attempt to deny it; we are not able to do it, and then it is presented to reflection as superior to all possible negation; it appears to us no longer only as a truth, but as a necessary truth.
Is it not also evident, that we do not begin by reflection, that reflection supposes an anterior operation, and that this operation, in order not to be one of reflection, and not to suppose another before it, must be entirely spontaneous; that thus the spontaneous and instinctive intuition of truth precedes its reflection and necessary conception?
Reflection is a progress more or less tardy in the individual and in the race. It is, par excellence, the philosophic faculty; it sometimes engenders doubt and skepticism, sometimes convictions that, for being rational, are only the more profound. It constructs systems, it creates artificial logic, and all those formulas which we now use by the force of habit as if they were natural to us. But spontaneous intuition is the true logic of nature. It presides over the acquisition of nearly all our cognitions. Children, the people, three-fourths of the human race never pass beyond it, and rest there with boundless security.
The question of the origin of human cognitions is thus resolved for us in the simplest manner: it is enough for us to determine that operation of the mind which precedes all others, without which no other would take place, and which is the first exercise, and the first form of our faculty of knowing.[29]
Since every thing that bears the character of reflection cannot be primitive, and supposes an anterior state, it follows, that the principles which are the subject of our study could not have possessed at first the reflective and abstract character with which they are now marked, that they must have shown themselves at their origin in some particular circumstance, under a concrete and determinate form, and that in time they were disengaged from this form, in order to be invested with their actual, abstract, and universal form. These are the two ends of the chain; it remains for us to seek how the human mind has been from one to the other, from the primitive state to the actual state, from the concrete state to the abstract state.
How can we go from the concrete to the abstract? Evidently by that well-known operation which is called abstraction. Thus far, nothing is more simple. But it is necessary to discriminate between two sorts of abstractions.
In presence of several particular objects, you omit the characters which distinguish them, and separately consider a character which is common to them all—you abstract this character. Examine the nature and conditions of this abstraction; it proceeds by means of comparison, and it is founded on a certain number of particular and different cases. Take an example: examine how we form the abstract and general idea of color. Place before my eyes for the first time a white object. Can I here at the first step immediately arrive at a general idea of color? Can I at first place on one side the whiteness, and on the other side the color? Analyze what passes within you. You experience a sensation of whiteness. Omit the individuality of this sensation, and you wholly destroy it; you cannot neglect the whiteness, and preserve or abstract the color; for, a single color being given, which is a white color, if you take away that, there remains to you absolutely nothing in regard to color. Let a blue object succeed this white object, then a red object, etc.; having sensations differing from each other, you can neglect their differences, and only consider what they have in common, that they are sensations of sight, that is to say, colors, and you thus obtain the abstract and general idea of color. Take another example: if you had never smelled but a single flower, the violet, for instance, would you have had the idea of odor in general? No. The odor of the violet would be for you the only odor, beyond which you would not seek, you could not even imagine another. But if to the odor of the violet is added that of the rose, and other different odors, in a greater or less number, provided there be several, and a comparison be possible, and consequently, knowledge of their differences and their resemblances, then you will be able to form the general idea of odor. What is there in common between the odor of one flower and that of another flower, except that they have been smelled by aid of the same organ, and by the same person? What here renders generalization possible, is the unity of the sentient subject which remembers having been modified, while remaining the same, by different sensations; now, this subject can feel itself identical under different modifications, and it can conceive in the qualities of the object felt some resemblance and some dissimilarity, only on the condition of a certain number of sensations experienced, of odors smelled. In that case, but in that case alone, there can be comparison, abstraction, and generalization, because there are different and similar elements.