piristic scepticism, the type of modern positivism, appeals also to a series of physiological and experimental facts. In his eight books on Pyrrhonism, valuable fragments of which have been preserved by Sextus,1 one of these doubters, ÆNESIDEMUS of Cnossus,2 develops the reasons which influenced Pyrrho and induced the author himself to call in question the possibility of certain knowledge. These reasons (TрÓTO тóжоι èπоxs) are as follows:

(1) The differences in the organization of sensible be ings, and the resulting different and sometimes contradictory impressions produced by the same objects. All things seem yellow to a man suffering from the jaundice. Similarly, the same object may be seen in different colors and in different proportions by each particular animal.

(2) The differences in the organization of human beings. If all things were perceived by us in the same way, we should all have the same impressions, the same ideas, the same emotions, the same desires; which is not the case.

(3) The differences in the different senses of the same individual. The same object may produce contrary impressions upon two different senses. A picture may impress the eye agreeably, the touch disagreeably; a bird may please the sense of sight and have an unpleasant effect upon the hearing. Besides, every sensible object appears to us as a combination of diverse elements: an apple, for example, is smooth, fragrant, sweet, yellow or red. Now, there are two possibilities. The fruit in question may be a simple object, which as such has neither

1 Sext. Emp., Hyp. Pyrrh., I., Diog. L., IX.; Ritter and Preller, pp. 481 ff.; V. Brochard, op. cit.

2 Born in Cnossus in Crete. Enesidemus (Aivnoidnμos) probably lived in Alexandria at the beginning of the Christian era. [See Saisset, Le Scepticisme. Enésidème, Pascal, Kant, 2d ed., Paris, 1867; Natorp, op. cit. - TR.].

smoothness nor sweetness nor color, but occasions an impression sui generis in each particular sense depending upon the particular nature of the sense-organ. But it is also possible that the apple is quite the reverse of simple; it may be still more complex than it appears to us; possibly it contains an infinite number of other very essential elements, of which we have no knowledge whatever, because the corresponding senses may be lacking.

(4) The circumstances in which the sensible subject is placed produce infinite differences in his impressions. During our waking states things appear otherwise than in sleep; in youth they affect us otherwise than in old age, in health, otherwise than in sickness, in the normal state of the brain, otherwise than in drunkenness.

(5) The uncertainty of knowledge resulting from the position, distance, and general topical relations of objects. A vessel seen at a distance seems stationary; a light burning in broad daylight is invisible; an elephant looks enormous near at hand, small at a certain distance; the neck of a pigeon changes its color according to the observer's point of vision. Phenomena are, therefore, always deter mined by the relative position of the object and its distance; and since the objects which we observe are necessarily in a certain position and at a certain distance, we may, indeed say what they are in such and such positions and at such and such distances, but not what they are independently of these relations. Experience never gives us anything but relative knowledge.

(6) No sensation is pure; foreign elements coming either from the external world or from ourselves are mixed with each. Sounds, for example, are different, according as the air is dense or rare. Spices emit a stronger odor in a room and when it is warm than in the open air and in the cold. Bodies are lighter in water than in air. We must also take into account what our own bodies and minds add

to the sensation. We must note the influence exercised on sensation by the eye, its tissues and its humors: an object that is green to my neighbor seems blue to me. Finally, we must take into consideration the influence of our understanding, the changes it may produce in the data furnished by the senses in order to convert them into ideas and notions.

(7) Qualities differ according to quantities. The horn of a goat (the whole) is black; the detached fragments (the parts) are whitish. Wine taken in small quantities has a strengthening effect; taken in large doses it weakens. Certain poisons are fatal when taken alone; in mixture with other substances, they cure.

(8) We perceive only phenomena and relations; we never perceive the things themselves. We know what they are in relation to other things and ourselves; we are absolutely ignorant of what they are in relation to themselves.

(9) A final and one of the strongest reasons for doubt is the influence of habit, education, and social and religious environment. We are accustomed to seeing the sun and are therefore indifferent to it; comets, however, are exceptional phenomena and consequently produce the most vivid im pressions in us. We esteem what is rare; we despise the common things, although the latter may have more real value than the former. For the Jew educated in the worship of Jehovah, Jupiter is but an idol; for the Greek, who has been taught to worship Jupiter, Jehovah is the false God. Had the Jew been born a Greek, and the Greek descended from the race of Abraham, the reverse would be true. The Jew abstains from bloody sacrifices, because his religion commands it; the Greek has no scruples whatever against the practice, because his priests find nothing objectionable therein. Different countries, differ ent customs! It seems as though we shall never be able

to say what God is in himself and independently of human notions, or to know right and wrong as such and apart from our conceptions.

The same philosopher subjects the notion of causality to a critique 1 the essential features of which are reproduced by David Hume. The causal relation is, according to Enesidemus, inconceivable for the corporeal as well as for the incorporeal world. Nor can it exist between bodies and minds. The efficient cause of a body cannot be a body; in fact, we cannot conceive how two can be derived from the unit, three from two, and so on. For the same reason, the efficient cause cannot be an immaterial entity. Besides, an immaterial being can neither touch matter nor be touched by it, neither act upon it nor be acted upon by it. The material cannot produce the immaterial, and vice versa, since the effect is necessarily of the same nature as the cause; a horse never produces a man, and vice versa. Now, with regard to objects which we call causes, it must be said that only bodies and immaterial beings exist. Hence, there are no causes in the proper sense of the term.

We reach the same conclusion in reference to motion and rest. Rest cannot produce motion, nor motion, rest. Similarly, rest cannot produce rest, nor motion, motion.

The cause is either simultaneous with, or antecedent to, or consequent upon, its effect. In the first case, the effect may be the cause, and the cause the effect; in the second, there is no effect as long as the cause acts, and there is no longer an acting cause as soon as the effect is produced. The third case is an absurd hypothesis.

What we call a cause must act by itself or through the mediation of something else. On the first hypothesis the cause would have to act always and in all cases, which is

1 Sextus Empiricus, Adv. math., IX., 220 ff.

disproved by experience; on the second, the intermediate cause may be the cause as well as the so-called cause.

The supposed cause possesses a single property or it pos sesses several. In the former case, the supposed cause must always act in the same manner under all circumstances; which is not true. The sun, for example, sometimes burns, sometimes warms without burning, and sometimes illuminates the object without burning or warming it; it hardens clay, tans the skin, and reddens fruits. Hence the sun has diverse properties. But, on the other hand, we cannot conceive how it can have them, because, if it had them, it would at once burn, and melt, and harden everything.

The objection that the effect produced by it depends on the nature of the object exposed to its rays makes for scepticism. It is equivalent to a confession that the hardened clay and the melted wax are as much causes as the sun; hence, that the real cause is the contact between the solar rays and the object acted upon. But the contact is exactly what we cannot conceive. For it is either indirect or im mediate. If indirect, there is no real contact; if direct, there is no contact either, but the two objects are united, fused, identified.

Passive action is as incomprehensible as efficient action To be passive or to suffer means to be diminished, to be deprived of being in a certain measure. In so far as I am passive, I am non-existent. Hence, to be passive means to be and not to be at the same time; which is contra dictory. Furthermore, the idea of becoming involves an evident contradiction; it is absurd to say that clay becomes hard or wax becomes soft, for it is assuming that clay is hard and soft, or wax soft and hard, at the same moment; it amounts to saying that what is not, is, and what is, is not. Hence, no becoming. Hence, also, no causality. The impossibility of causality means that be coming is impossible.