The Homeric poems Iliad and Odyssey (probably eighth century BCE) are of interest to the historian of philosophy because they provide the background, in languagePage 459  |  Top of Article and to some extent in thought, from which Greek philosophy emerged. The hexameters of Parmenides and Empedocles follow the Homeric pattern closely, and they both use Homeric words and coin words for themselves after the Homeric model. They also sometimes use the same thought forms. For instance, a comparison may be drawn between Parmenides' journey (see Fr. 1) and Odysseus's journey to the underworld (Odyssey, Book 11). The Homeric simile is the forerunner of the natural philosopher's "working model," by which an unfamiliar process is explained by comparison with a more familiar one. For example, to illuminate his description of an evenly poised battle Homer introduced a "careful working woman" weighing wool in her scales; Empedocles compared the breathing process in animals with operations performed with a household instrument, the clepsydra.

Apart from these questions of language and style, the Iliad and the Odyssey influenced the content of later philosophical thought in various ways.

The Homeric world picture was of a flat, disk-shaped earth, with the sky set over the top like an inverted metal bowl and Hades underneath the earth in a more or less symmetrical relation to the sky. The sun, moon, and stars were taken to move across the fixed heaven from east to west, but the manner of their return journey was not clear. The space between the earth and the sky contained aer (mist), and above that was aether (the bright air of the upper heavens). The earth was completely surrounded by the river of Ocean, personified and deified as Okeanos. In one exceptional passage (Iliad, Book 14, 200–248) Okeanos is called "the begetter of gods" and "the begetter of all things." Aristotle (Metaphysics A 3, 982b27) half seriously suggested that Homer's Okeanos was the forerunner of Thales' cosmogonical water. Plato, even less seriously, suggested (Theaetetus 152E) that Okeanos provided the origin of Heraclitus's flux theory. These are far-fetched ideas; the cosmology of Homer, such as it was, can hardly be seen as anything but a contrast with Ionian theories (see G. S. Kirk in The Presocratic Philosophers, Ch 1). But connections can be traced between some details of Homer's descriptions of the natural world and the speculations of later Greek philosophers of nature (see Charles Mugler, Les origines de la science grecque chez Homère).

The historian Herodotus observed that Homer and Hesiod together had determined for all the Greeks what their gods were like, and this is probably the greatest significance of the Homeric poems for the history of philosophy (History II, 53). There is one general feature about the Homeric gods that is of much importance: They were not dark gods, accessible only to mystics and appeasable by magic, but on the whole very human and rational. They had powers over the world of human experience, and their powers were defined and hierarchical; in this we can see a hint of the orderly cosmos of later theory.

Some philosophers objected to the Homeric gods. Xenophanes launched the first attack: The gods behaved immorally; moreover, the conception of them was relative to the believer (see Fr. 16: "Ethiopians imagine their gods as black and snub-nosed"). Heraclitus's objections were not explicitly against gods but against Homer as the educator of Greece; the Olympian gods were, however, near the center of his target. Plato's onslaught in the Republic (376Eff.) is well known; he wished to censor everything in the Homeric poems that was discreditable to the gods before the poems could be used in the education of the "Guardians" (it was general practice in Greece both before and after Plato's time to use Homer as the basis for moral and religious education).

The Homeric view of man shows interesting differences from later theories. There was no unified soul, contrasted with body, as in the Pythagorean-Platonic tradition; instead, the psychic functions were distributed without much consistency over a number of entities. The psyche, which held the position of greatest importance from the time of Pythagoras, was merely a life-soul in Homer; it played no part in the thoughts, emotions, and actions of the living man. The psyche survived after death; it did not, however, retain the complete moral personality, as in the Platonic eschatology, but was a bloodless, helpless shadow. The thoughts and feelings of the living man were attributed to the phrenes (roughly speaking, the organs of the chest, although in later Greek the word means "diaphragm"), the heart, and the thymos (a mysterious entity probably connected, like psyche, with breath). Nous (mind), which became the most important part of the psyche in the psychology of Plato and Aristotle, was generally restricted in Homer to the intuitive understanding of a situation (like the English "to see" in its metaphorical sense); consequently, it was often connected with sense perception, not contrasted with it as in Plato. Unlike phrenes, nous was not a physical thing for Homer but a function.

The actions of the human characters in the Iliad and Odyssey are represented as being influenced or manipulated more or less constantly by the gods. Actions that might be otherwise difficult to explain, such as a sudden access of superhuman courage, are especially attributed to the intervention of a god. But it is not only the inexplicable or the uncharacteristic that is described thus; a successful shot with the spear or an unsuccessful one, a plan adopted, a fit of anger, a bad bargain, an untimely sleep—these and many other unremarkable events are described as caused by a god. The gods handle the heroes as arbitrarily as a mortal king might treat his subjects, although not, as a rule, with savagery.

The fact that so much of human action is attributed to the gods has led modern interpreters to say that Homeric man is "an open field," that Homer denies free will, and that he has no concept of the human personality. This is true in a sense, but it is misleading. Homer was not a philosopher who had confronted the free-will problem and decided upon determinism; apart from an occasional exception he offered no theories about motivation and responsibility. From the point of view of the responsibility of human characters, there is no opposition between "caused by a god" and "due to a human agent"; for example, one and the same attack by Sarpedon is described as due to Zeus and a few lines later as due to Sarpedon's thymos (Iliad, Book 11, 292 and 307). The moral relations between human beings are on the whole, although not entirely, unaffected by the interventions of the gods; a god may stir a man to excessive anger, but it is still felt appropriate to blame the man for his anger. The individual characters of the heroes remain fairly stable; the activity of the gods is not such as to make human beings unpredictable. But the Homeric poems generally show a limited sense of moral responsibility. They were composed at a time when shame still predominated over guilt as a motivating force, and the intention of the agent and his knowledge of the circumstances of his act (the two factors that of course played the chief part in later legal and philosophical theories of responsibility) receive little attention.

Homer provided the material for much of later Greek literature, which examined the relation of Homeric gods and men in a new way. The problem of individual human responsibility for actions in which gods were said to be involved, though hardly seen by Homer, was much discussed by the fifth-century tragedians and Sophists (see, for example, Aeschylus, Agamemnon 1497ff.; Euripides, Troades 914ff.; Gorgias, Helen).