Greek philosophy

Monistic cosmologies

There is a consensus, dating back at least to the 4th century bce and continuing to the present, that the first Greek philosopher was Thales of Miletus (flourished 6th century bce). In Thales’ time the word philosopher (“lover of wisdom”) had not yet been coined. Thales was counted, however, among the legendary Seven Wise Men (Sophoi), whose name derives from a term that then designated inventiveness and practical wisdom rather than speculative insight. Thales demonstrated these qualities by trying to give the mathematical knowledge that he derived from the Babylonians a more exact foundation and by using it for the solution of practical problems—such as the determination of the distance of a ship as seen from the shore or of the height of the Egyptian pyramids. Although he was also credited with predicting an eclipse of the Sun, it is likely that he merely gave a natural explanation of one on the basis of Babylonian astronomical knowledge.

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Thales is considered the first Greek philosopher because he was the first to give a purely natural explanation of the origin of the world, free from mythological ingredients. He held that everything had come out of water—an explanation based on the discovery of fossil sea animals far inland. His tendency (and that of his immediate successors) to give nonmythological explanations was undoubtedly prompted by the fact that all of them lived on the coast of Asia Minor, surrounded by a number of nations whose civilizations were much further advanced than that of the Greeks and whose own mythological explanations varied greatly. It appeared necessary, therefore, to make a fresh start on the basis of what a person could observe and infer by looking at the world as it presented itself. This procedure naturally resulted in a tendency to make sweeping generalizations on the basis of rather restricted, though carefully checked, observations.

Thales’ disciple and successor, Anaximander of Miletus (610–c. 546 bce), tried to give a more elaborate account of the origin and development of the ordered world (the cosmos). According to him, it developed out of the apeiron (“unlimited”), something both infinite and indefinite (without distinguishable qualities). Within this apeiron something arose to produce the opposites of hot and cold. These at once began to struggle with each other and produced the cosmos. The cold (and wet) partly dried up (becoming solid earth), partly remained (as water), and—by means of the hot—partly evaporated (becoming air and mist), its evaporating part (by expansion) splitting up the hot into fiery rings, which surround the whole cosmos. Because these rings are enveloped by mist, however, there remain only certain breathing holes that are visible to human beings, appearing to them as the Sun, Moon, and stars. Anaximander was the first to realize that upward and downward are not absolute but that downward means toward the middle of the Earth and upward away from it, so that the Earth had no need to be supported (as Thales had believed) by anything. Starting from Thales’ observations, Anaximander tried to reconstruct the development of life in more detail. Life, being closely bound up with moisture, originated in the sea. All land animals, he held, are descendants of sea animals; because the first humans as newborn infants could not have survived without parents, Anaximander believed that they were born within an animal of another kind—specifically, a sea animal in which they were nurtured until they could fend for themselves. Gradually, however, the moisture will be partly evaporated until in the end all things will return into the undifferentiated apeiron, “in order to pay the penalty for their injustice”—that of having struggled against one another.

Anaximander’s successor, Anaximenes of Miletus (flourished c. 545 bce), taught that air was the origin of all things. His position was for a long time thought to have been a step backward because, like Thales, he placed a special kind of matter at the beginning of the development of the world. But this criticism missed the point. Neither Thales nor Anaximander appear to have specified the way in which the other things arose out of water or apeiron. Anaximenes, however, declared that the other types of matter arose out of air by condensation and rarefaction. In this way, what to Thales had been merely a beginning became a fundamental principle that remained essentially the same through all of its transmutations. Thus, the term arche, which originally simply meant “beginning,” acquired the new meaning of “principle,” a term that henceforth played an enormous role in philosophy down to the present. This concept of a principle that remains the same through many transmutations is, furthermore, the presupposition of the idea that nothing can come out of nothing and that all of the comings to be and passings away that human beings observe are nothing but transmutations of something that essentially remains the same eternally. In this way it also lies at the bottom of all of the conservation laws—the laws of the conservation of matter, force, and energy—that have been basic in the development of physics. Although Anaximenes of course did not realize all of the implications of his idea, its importance can hardly be exaggerated.

The first three Greek philosophers have often been called “hylozoists,” because they seemed to believe in a kind of living matter (see hylozoism). But this is hardly an adequate characterization. It is, rather, characteristic of them that they did not clearly distinguish between kinds of matter, forces, and qualities, nor between physical and emotional qualities. The same entity is sometimes called “fire” and sometimes “the hot.” Heat appears sometimes as a force and sometimes as a quality, and again there is no clear distinction between warm and cold as physical qualities and the warmth of love and the cold of hate. To realize these ambiguities is important to an understanding of certain later developments in Greek philosophy.

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Xenophanes of Colophon (c. 560–c. 478 bce), a rhapsodist and philosophical thinker who emigrated from Asia Minor to Elea in southern Italy, was the first to articulate more clearly what was implied in Anaximenes’ philosophy. He criticized the popular notions of the gods, saying that people made the gods in their own image. But, more importantly, he argued that there could be only one God, the ruler of the universe, who must be eternal. For, being the strongest of all beings, he could not have come out of something less strong, nor could he be overcome or superseded by something else, because nothing could arise that is stronger than the strongest. The argument clearly rested on the axioms that nothing can come out of nothing and that nothing that exists can vanish.

These axioms were made more explicit and carried to their logical (and extreme) conclusions by Parmenides of Elea (born c. 515 bce), the founder of the so-called school of Eleaticism, of whom Xenophanes has been regarded as the teacher and forerunner. In a philosophical poem, Parmenides insisted that “what is” cannot have come into being and cannot pass away because it would have to have come out of nothing or to become nothing, whereas nothing by its very nature does not exist. There can be no motion either, for it would have to be a motion into something that is—which is not possible since it would be blocked—or a motion into something that is not—which is equally impossible since what is not does not exist. Hence, everything is solid, immobile being. The familiar world, in which things move around, come into being, and pass away, is a world of mere belief (doxa). In a second part of the poem, however, Parmenides tried to give an analytical account of this world of belief, showing that it rested on constant distinctions between what is believed to be positive—i.e., to have real being, such as light and warmth—and what is believed to be negative—i.e., the absence of positive being, such as darkness and cold.

It is significant that Heracleitus of Ephesus (c. 540–c. 480 bce), whose philosophy was later considered to be the very opposite of Parmenides’ philosophy of immobile being, came, in some fragments of his work, near to what Parmenides tried to show: the positive and the negative, he said, are merely different views of the same thing; death and life, day and night, and light and darkness are really one.

Pluralistic cosmologies

Parmenides had an enormous influence on the further development of philosophy. Most of the philosophers of the following two generations tried to find a way to reconcile his thesis that nothing comes into being nor passes away with the evidence presented to the senses. Empedocles of Acragas (c. 490–430 bce) declared that there are four material elements (he called them the roots of everything) and two forces, love and hate, that did not come into being and would never pass away, increase, or diminish. But the elements are constantly mixed with one another by love and again separated by hate. Thus, through mixture and decomposition, composite things come into being and pass away. Because Empedocles conceived of love and hate as blind forces, he had to explain how, through random motion, living beings could emerge. This he did by means of a somewhat crude anticipation of the theory of the survival of the fittest. In the process of mixture and decomposition, the limbs and parts of various animals would be formed by chance. But they could not survive on their own; they would survive only when, by chance, they had come together in such a way that they were able to support and reproduce themselves. It was in this way that the various species were produced and continued to exist.

Anaxagoras of Clazomenae (c. 500–c. 428 bce), a pluralist, believed that because nothing can really come into being, everything must be contained in everything, but in the form of infinitely small parts. In the beginning, all of these particles had existed in an even mixture, in which nothing could be distinguished, much like the indefinite apeiron of Anaximander. But then nous, or intelligence, began at one point to set these particles into a whirling motion, foreseeing that in this way they would become separated from one another and then recombine in the most various ways so as to produce gradually the world in which human beings live. In contrast to the forces assumed by Empedocles, the nous of Anaxagoras is not blind but foresees and intends the production of the cosmos, including living and intelligent beings; however, it does not interfere with the process after having started the whirling motion. This is a strange combination of a mechanical and a nonmechanical explanation of the world.

By far of greatest importance for the later development of philosophy and physical science was an attempt by the atomists Leucippus (flourished 5th century bce) and Democritus (c. 460–c. 370 bce) to solve the Parmenidean problem. Leucippus found the solution in the assumption that, contrary to Parmenides’ argument, the nothing does in a way exist—as empty space. There are, then, two fundamental principles of the physical world, empty space and filled space—the latter consisting of atoms that, in contrast to those of modern physics, are real atoms; that is, they are absolutely indivisible because nothing can penetrate to split them. On these foundations, laid by Leucippus, Democritus appears to have built a whole system, aiming at a complete explanation of the varied phenomena of the visible world by means of an analysis of its atomic structure. This system begins with elementary physical problems, such as why a hard body can be lighter than a softer one. The explanation is that the heavier body contains more atoms, which are equally distributed and of round shape; the lighter body, however, has fewer atoms, most of which have hooks by which they form rigid gratings. The system ends with educational and ethical questions. A sound and cheerful person, useful to his fellows, is literally well composed. Although destructive passions involve violent, long-distance atomic motions, education can help to contain them, creating a better composure. Democritus also developed a theory of the evolution of culture, which influenced later thinkers. Civilization, he thought, is produced by the needs of life, which compel human beings to work and to make inventions. When life becomes too easy because all needs are met, there is a danger that civilization will decay as people become unruly and negligent.