[1. Canonical Philosophy.]
Epicurus gave the name of Canonic to what is really a system of logic, in which he defines the criteria of truth, in regard to the theoretic, as in fact sensuous perceptions, and, further, as conceptions or anticipations (προλήψεις); in regard to the practical, as the passions, impulses, and affections.[148]
a. On the theoretic side the criterion, closely considered, has, according to Epicurus, three moments, which are the three stages of knowledge; first, sensuous perception, as the side of the external; secondly, ordinary conception, as the side of the internal; thirdly, opinion (δόξα), as the union of the two.
α. “Sensuous perception is devoid of reason,” being what is given absolutely. “For it is not moved by itself, nor can it, if if is moved by something else, take away from or add to” that which it is, but it is exactly what it is. “It is beyond criticism or refutation. For neither can one sensation judge another, both being alike, since both have equal authority;”—when the presentations of sight are of the same kind, every one of them must admit the truth of all the rest. “Nor can one of them pass judgment on another when they are unlike, for they each have their value as differing;” red and blue, for example, are each something individual. “Nor can one sensation pass judgment on another when they are heterogeneous; for we give heed to all. Thought, in the same way, cannot criticize the senses; for all thought itself depends on the sensation,” which forms its content. But sensuous perception may go far wrong. “The truth of what our senses perceive is first evinced by this, that the power of perception remains with us; sight and hearing are permanent powers of this kind as much as the capacity of feeling pain. In this way even the unknown” (the unperceived) “may be indicated by means of that which appears” (perception). Of this conception of objects of perception which are not immediate we shall have to speak more particularly hereafter (p. 292) in dealing with physical science. “Thus all” (unknown, imperceptible) “thoughts originated in the senses either directly in respect of their chance origin or in respect of relationship, analogy, and combination; to these operations thought also contributes something,” namely as the formal connection of the sensuous conceptions. “The fancies of the insane or of our dreams are also true; for they act upon us, but that which is not real does not act.”[149] Thus every sensuous perception is explicitly true, in so far as it shows itself to be abiding, and that which is not apparent to our senses must be apprehended after the same manner as the perception known to us. We hear Epicurus say, just as we hear it said in everyday life: What I see and hear, or, speaking generally, what I perceive by my senses, comprises the existent; every such object of sense exists on its own account, one of them does not contradict the other, but all are on the same level of validity, and reciprocally indifferent. These objects of perception are themselves the material and content of thought, inasmuch as thought is continually making use of the images of these things.
β. “Ordinary conception is now a sort of comprehension (κατάληψις), or correct opinion or thought, or the universal indwelling power of thinking; that is to say, it is the recollection of that which has often appeared to us,”—the picture. “For instance, when I say, ‘this is a man,’ I, with the help of previous perceptions, at once by my power of representation recognize his form.” By dint of this repetition the sensuous perception becomes a permanent conception in me, which asserts itself; that is the real foundation of all that we hold true. These representations are universal, but certainly the Epicureans have not placed universality in the form of thinking, but only said it is caused by frequency of appearance. This is further confirmed by the name which is given to the image which has thus arisen within us. “Everything has its evidence (ἐναργές) in the name first conferred on it.”[150] The name is the ratification of the perception. The evidence which Epicurus terms ἐνάργεια is just the recognition of the sensuous through subsumption under the conceptions already possessed, and to which the name gives permanence; the evidence of a conception is therefore this, that we affirm an object perceptible by the senses to correspond with the image. That is the acquiescence which we have found taking place with the Stoics when thought gives its assent to a content; thought, however, which recognizes the thing as its own, and receives it into itself, with the Stoics remained formal only. With Epicurus the unity of the conception of the object with itself exists also as a remembrance in consciousness, which, however, proceeds from the senses; the image, the conception, is what harmonizes with a sense-perception. The recognition of the object is here an apprehension, not as an object of thought, but as an object of imagination; for apprehension belongs to recollection, to memory. The name, it is true, is something universal, belongs to thinking, makes the manifold simple, yea, is in a high degree ideal; but in such a way that its meaning and its content are the sensuous, and are not thus to be counted as simple, but as sensuous. In this way opinion is established instead of knowledge.
γ. In the last place, opinion is nothing but the reference of that general conception, which we have within us, to an object, a perception, or to the testimony of the senses; and that is the passing of a judgment. For in a conception we have anticipated that which comes directly before our eyes; and by this standard we pronounce whether something is a man, a tree, or not. “Opinion depends on something already evident to us, to which we refer when we ask how we know that this is a man or not. This opinion is also itself termed conception, and it may be either true or false:—true, when what we see before our eyes is corroborated or not contradicted by the testimony of the conception; false in the opposite case.”[151] That is to say, in opinion we apply a conception which we already possess, or the type, to an object which is before us, and which we then examine to see if it corresponds with our mental representation of it. Opinion is true if it corresponds with the type; and it has its criterion in perceiving whether it repeats itself as it was before or not. This is the whole of the ordinary process in consciousness, when it begins to reflect. When we have the conception, it requires the testimony that we have seen or still see the object in question. From the sensuous perceptions blue, sour, sweet, and so on, the general conceptions which we possess are formed; and when an object again comes before us, we recognize that this image corresponds with this object. This is the whole criterion, and a very trivial process it is; for it goes no further than the first beginnings of the sensuous consciousness, the immediate perception of an object. The next stage is without doubt this, that the first perception forms itself into a general image, and then the object which is present is subsumed under the general image. That kind of truth which anything has of which it can only be said that the evidence of the senses does not contradict it, is possessed by the conceptions of the unseen, for instance, the apprehension of heavenly phenomena: here we cannot approach nearer, we can see something indeed, but we cannot have the sensuous perception of it in its completeness; we therefore apply to it what we already know by other perceptions, if there is but some circumstance therein which is also present in that other perception or conception (supra, p. 282).
b. From these external perceptions of objects presently existing, with which we here began, the affections, the internal perceptions, which give the criteria for practical life are however distinguished; they are of two kinds, either pleasant or unpleasant. That is to say, they have as their content pleasure or satisfaction, and pain: the first, as that which peculiarly belongs to the perceiver, is the positive; but pain, as something alien to him, is the negative. It is these sensuous perceptions which determine action; they are the material from which general conceptions regarding what causes me pain or pleasure are formed; as being permanent they are therefore again conceptions, and opinion is again this reference of conception to perception, according to which I pass judgment on objects—affections, desires, and so on.[152] It is by this opinion, therefore, that the decision to do or to avoid anything is arrived at.
This constitutes the whole Canon of Epicurus, the universal standard of truth; it is so simple that nothing can well be simpler, and yet it is very abstract. It consists of ordinary psychological conceptions which are correct on the whole, but quite superficial; it is the mechanical view of conception having respect to the first beginnings of observation. But beyond this there lies another and quite different sphere, a field that contains determinations in themselves; and these are the criteria by which the statements of Epicurus must be judged. Nowadays even Sceptics are fond of speaking of facts of consciousness; this sort of talk goes no further than the Epicurean Canon.
[2. Metaphysics.]
In the second place, Epicurus enters on a metaphysical explanation of how we are related to the object; for sensuous perception and outside impressions he unhesitatingly regards as our relation to external things, so that he places the conceptions in me, the objects outside of me. In raising the question of how we come by our conceptions, there lies a double question: on the one hand, since sense-perceptions are not like conceptions, but require an external object, what is the objective manner in which the images of external things enter into us? On the other hand, it may be asked how conceptions of such things as are not matter of perception arise in us; this seems to be an activity of thought, which derives conceptions such as these from other conceptions; we shall, however, see presently (pp. 287, 288) and more in detail, how the soul, which is here related to the object in independent activity, arrives at such a point.