As in the discussion of law and normative behavior, we can say that what was no religious problem at all for the average believer could be a serious issue for the philosopher. Thus, the heterogeneity of the pantheon, with any number of, for instance, Aphrodites in as many places or sanctuaries, would be accepted unquestioningly by believers paying homage to those goddesses. Or should that be: that goddess? Struggling with such phenomena, and with the old problem of the theodicy (the moral dilemma caused by the fact that often the good seem to be punished while the wicked prosper), the philosophically minded could come up with ideas ranging from the monotheistic (all these gods are emanations of what is, in fact, a single god or divine power) to the outright atheistic. The Ionic philosopher Anaxagoras (ca. 500-425 BC) developed a materialist vision of the world in which there was but little room for the gods, and Diogenes of Sinope (ca. 400-325 BC) rejected all societal conventions and preached anaideia, shamelessness. For this, he was called a kuon, a dog, which name his followers took as a sobriquet to carry with pride: the Kunikoi, or the Cynics.
All of this can be seen as part of a process of secularization that affected many aspects of ancient society (without ever approaching the degree of secularization seen in parts of the contemporary world). The 5th-century medical doctor, Hippocrates, was looking for natural, not supernatural, causes of human illness. His contemporary, the historian Thucydides, left no room for divine intervention in the course of history. The sophist Protagoras argued for the relativity of all knowledge (which is the meaning of his famous saying “man is the measure of all things”), and this general skepticism led to an agnostic stance toward the gods, though he does not seem to have contested conventional morality, as some of the other sophists did. The polis, however, did not stand by to watch its values being undermined, not even open-minded Athens. Anaxagoras was banished for asebeia, and the trial of Socrates has already been mentioned. But the genie was out of the bottle: even when one does not doubt the existence of the gods, still the relationship between god, fate, and individual responsibility is a theme that was discussed widely in the 5th and 4th centuries BC. And even ordinary believers would sometimes be confronted with such questions: they are exactly the conundrums that the authors of Athenian tragedy analyze in their plays.
A representative of rather less radical strands of Greek thought, who did remain within the thought patterns of the polis, is Plato. Plato (429-347 BC) rejected the ideas of sophists and cynics. The relativism of the first he opposed with a new idealism, and the individualism of the second he confronted with a new sense of community. Plato’s theory of forms or ideas held that the idea was reality, not its inadequate shadow which most people call reality: ideas were eternal and unchanging. Ideas are not to be grasped by our senses, but we can know them by a process of thought. Once we know the ideas, we know the unchanging and absolute norms. Consequently, philosophers, or more specifically Platonic philosophers, are the ones designated to lead humankind in the right direction. Despite his original political aspirations, Plato never came near a position of leadership in the Athenian polis. He spent most of his life teaching others his philosophy, in his own school just outside Athens, near the sanctuary of the heros Hekademos, hence its name: Akademeia. In his
Politeia and his Nomoi, Plato designed an earthly polis that came closest to his ideal polis. It is a blueprint for a brave new world where the two lower classes of farmer-craftsmen and soldiers are ruled over by an upper class of dictatorial philosopher-magistrates. His polis leaves little or no room for dissident voices. Plato tried to interest the tyrant Dionysius II of Syracuse and his successor in putting these ideas into practice, but to no avail.
Aristotle was the most important pupil of Plato’s Academy. But although much influenced by Plato, Aristotle’s philosophy developed in quite a different direction, without any room for Plato’s world of ideas. Aristotle advocated an empirical, inductive way of thinking instead of a deductive one. This time, it is the observable world that occupies the center stage, although Aristotle did not rely exclusively on our senses, but also attributed an important role to the mind. Of Aristotle’s oeuvre, we have more strictly philosophical writings, on logic, ethics, and metaphysics, but also a large body of work on zoology, geography, ethnology, history, and some mathematics and astronomy. There was little that this great thinker did not occupy himself with. Aristotle’s classifications are still at the basis of our modern scholarship and science, and we constantly use concepts that he introduced, such as premise, conclusion, subject, attribute, matter, and so on.
In Aristotle’s work on institutions, one can see his inductive approach at work: he made an inventory of the different political arrangements of his own day, and his ideal polis is an eclectic combination of what he thought was best among existing systems of governance. In his polis, there is a hierarchy on the basis of wealth and of seniority. Only those whose income ensures that they will have enough spare time can become actively involved in politics, and one’s age determines the nature of the role. Aristotle’s ideas were never realized either: we do not know of any political influence he may have had in Athens. Aristotle had for a number of years been the educator of the Macedonian prince Alexander, who would become known to all the world as Alexander the Great, but whether we see in Alexander’s career anything that can be traced back to Aristotle’s teaching is doubtful. Maybe the fact that Alexander thought highly of intellectual pursuits is the only really obvious result of Aristotle’s troubles. Aristotle, like Plato, spend much of his life in his own school, at the eastern end of the city of Athens near the sacred grove of Apollo Lukeios and the Muses, hence the Lukeion, or Lyceum. The covered walkways there (the peripatos) gave the Aristotelian philosophy the epithet “peripatetic.”
Plato and Aristotle had a conservative view of the Greek polis, however different their approach may be. Both looked back at the heydays of the polis and wondered how, in less prosperous times, the polis could be put on a new track. They did not pick up the trends of the 4th century BC, where there was a move in the direction of monarchies. It is true that their ideal poleis have elements that favor the idea of a single ruler: although they were combating the sophists, they were both influenced by sophistic ideas, among them the concept of a monarch. These classical Greek philosophers did not have much of an impact on their own world. But the influence of these thinkers, Plato and Aristotle above all others, on the post-antiquity world has been immeasurably large.