Lives and Opinions of Eminent Philosophers

​And Andron of Argos, as Aristotle says, traversed waterless Libya without drinking. Moreover, one desires medicine, another agriculture, and another commerce; and the same things harm some but benefit others; whence one must suspend judgment. The third mode is that based on the differences among the sensory passages. An apple, for instance, presents itself as pale to the sight, sweet to the taste, and fragrant to the smell. And the very same form is viewed as of a different sort depending on the differences among mirrors. It follows, therefore, that what appears is no more of such a kind than of a different kind.

​The fourth mode is that based on conditions and general alterations, such as health, disease, sleep, waking, joy, grief, youth, old age, boldness, fear, want, fullness, hatred, friendship, warmth, cold; depending on breathing, or depending on the compression of the passages. The impressions that present themselves, therefore, appear of a different sort according to the particular conditions. For not even the mad are in an unnatural condition; for why should they be so any more than we? For we too see the sun as standing still. And Theon of Tithorea the Stoic used to walk about asleep during his slumber, as did the slave of Pericles on the edge of the roof.

​The fifth mode is that based on customs, laws, mythical beliefs, ethnic compacts, and dogmatic suppositions. In this are contained the matters concerning the fine and the base, the true and the false, the good and the bad, the gods, and the generation and destruction of all appearing things. The same thing, at any rate, is just among some, but unjust among others; and good to some, but bad to others. For the Persians do not consider it strange to have intercourse with a daughter, but the Greeks deem it unlawful. And the Massagetae, as Eudoxus also says in the first book of the Circuit of the Earth, have their women in common, but the Greeks do not; and the Cilicians used to take pleasure in piracy, but not the Greeks.

​People also consider different beings to be gods; and some hold that they exercise providence, while others do not. As for burial, the Egyptians bury by embalming, the Romans by burning, and the Paeonians by casting into lakes; whence suspension of judgment concerning the truth arises. The sixth mode is that based on mixtures and associations, according to which nothing appears purely by itself, but together with air, light, moisture, solidity, heat, coldness, motion, vapors, and other forces. Purple dye, for instance, displays a different color in sunlight, moonlight, and lamp-light. And our own complexion appears of a different sort at midday and at sunset; and a stone that in air is lifted by two men

​is easily moved in water, either because it is heavy and made light by the water, or because it is light and made heavy by the air. We are ignorant, then, of its intrinsic nature, just as of the oil in an ointment. The seventh mode is that based on distances, particular positions, places, and the things within those places. According to this mode, things thought to be large appear small, square things appear round, smooth things appear to have projections, straight things appear bent, and pale things appear of another color. The sun, for instance, appears small because of the distance; and mountains from afar appear air-like and smooth, but from near at hand rugged.

​Furthermore, the sun appears of a different sort when rising, and not similar when at mid-heaven. And the same body appears of one sort in a grove, but different on bare ground; and a portrait varies according to its particular position, as does the neck of a dove according to its turning. Since, therefore, it is not possible to comprehend these things apart from places and positions, their nature is unknown. The eighth mode is that based on their quantities and qualities, or degrees of heat, coldness, swiftness, slowness, paleness, or diversity of color. Wine, for instance, taken in moderation strengthens, but in larger quantity weakens; and similarly with food and like things.