Discussions
Map compliments of the Oxford Classical Dictionary. See https://oxfordre.com/classics/page/maps/maps-of-the-ancient-world.
Studies
The Presocratics
The philosophers before Socrates focused on how the world arose and how it works. They wrote speculatively about nature and the cosmos. Some challenged the possibility of science. And some emphasized practical studies about how people can get along or get ahead in the world. Their speculations led to advances in scientific knowledge.
Socrates
Socrates turned away from cosmology, and while he was fascinated with efforts of the Sophists to pursue on practical subjects, he himself insisted that what we should concern ourselves with was not our own success but what is right and wrong, good an evil. He turned philosophy towards ethics and moral theory.
Plato
A follower of Socrates, Plato wished to put the study of ethics on a firm foundation by developing a science of reality, or metaphysics, a science of knowledge, or epistemology, and studies of political science, education, aesthetics, and, eventually, natural science. He saw the world of experience as subject to an ideal realm.
Aristotle
A student of Plato, Aristotle never accepted his mentor's focus on the ideal realities of another world. He saw the ground of reality as concrete physical objects, from which ideal or universal entities were but abstractions. He developed a powerful account of science, and divided knowledge into most of the departmental studies that make up the modern curriculum.
Early Science
Early Greek science was deeply influenced by most of the early thinkers. The Presocratics believed in making and testing hypotheses. They invented concepts such as those of sources, principles, elements, compounds, atoms and empty space. Aristotle formalized logic and also took over the concept of a logic of scientific discovery and proof from Plato.
Recent Discussions
22.6 The Battle of Gods and Giants
The Visitor from Elea now closes the discussion about what-is-not and turns his attention to what-is. He describes a contemporary debate in mythological terms, as being like a battle of gods and giants, reminiscent of some scenes in Hesiod’s Theogony.[22] One group, the giants, identifies body (sōma) with being and refuses to consider any non-physical entity as real. The opposing group, the gods, stoutly maintains that certain intelligible incorporeal forms (noēta atta kai asōmata eidē) are what is really real, and that the bodies championed by their opponents are no
22.5 The Being of Being
Plato now begins an intense investigation into what-is. If you say that there are two things, such as hot and cold, says the Visitor, are you not saying that each of them is? And if they are, then we must recognize a third thing, namely Being. But Parmenides and his school want to say that there is only one thing. That thing, presumably, is Being. But they say that what-is is one. So now we have two names for one thing, ‘being’ and ‘one.’ But a name must be different
22.4 Presocratic Progress
Aristotle, who pays more attention to the early history of his discipline than Plato, gives a more extended and slightly more coherent story, but one that is still rudimentary and unsatisfactory.[11] A more satisfactory story is as follows.[12] The earliest philosophers, all from Ionia, on the Aegean coast of Anatolia, were pluralists. They thought there were several kinds of matter. Some of them (Anaximenes, and perhaps Thales, and possibly Xenophanes) thought there was one basic or default kind of matter (air, water, earth) that turned into other kinds of matter
22.3 Presocratic Debates
Plato now turns to a brief survey of early Greek thought, presumably to put Parmenides in his historic context. Each early thinker, according to the Visitor, “it seems to me, tells us a story as if we were children, one that there are three beings, which quarrel with each other over some things, then make up, marry, have children, and bring them up. Another says there are two, wet and dry or hot and cold, and they marry and give in marriage.” Next we meet the Eleatics, starting with Xenophanes
22.2 Appearance and Reality
The Visitor claims to be amazed at the sophists’ ability to make young people believe that they know everything about everything. They are good at feigning knowledge, but what they possess cannot be a true understanding, but only plausible beliefs. In fact, the sophists must promote false beliefs. Yet the claim that there are false beliefs is problematic in the Eleatic tradition, because according to Parmenides you can’t even entertain false beliefs. The Visitor quotes two lines from Parmenides’ poem: Never shall this prevail, that things that are-not are.
22.1 Sophistry, Bad and Good
The discussion depicted in Plato’s Sophist takes place the day after the that of the Theaetetus. Socrates meets with Theodorus the mathematician from Cyrene and his young student Theaetetus, the speakers of the previous dialogue (Plato ch. 21*). Theodorus also brings a Visitor from Elea, the hometown of Parmenides and Zeno, the main figures of the Eleatic school. This unnamed visitor will be the questioner-in-chief of the dialogue. He will bring the authority of the Eleatic school to the discussion, and presumably supply what Socrates cannot—an answer to the still-unanswered
21.8 Knowledge as True Judgment with an Account
Now Theaetetus remembers hearing someone say that knowledge is true judgment with an account (logos). According to his source, things that lacked an account were not knowable. Socrates offers a “dream” to help clarify the proposed definition. “I think I have heard people saying that the first components, like elements (stoicheia), from which we and everything else are composed, lack an account.” This, according to ancient commentators, is the first extant use of the term stoicheion as ‘element.’[56] This suggests the analogy to letters of the alphabet (also called stoicheia),
21.7 Knowledge as True Judgment
Overwhelmed by objections to the thesis that knowledge is perception, Theaetetus abandons it. Socrates asks him for another definition. He replies, it consists of judging (doxazein). Socrates plods him to be more specific. Theaetetus observes that there is false as well as true judgment, so “True judgment would have to be knowledge.”[52] Socrates addresses the question of false judgment, which has remained a thorny problem in Greek philosophy. In Greek idiom the phrase legein ouden, literally: ‘say nothing’ means to speak falsely or lie. But how can one say
21.6 Heraclitus Redivivus
Plato allowed Protagoras to defend himself against a too-hasty refutation. He does not offer the same opportunity to Heraclitus. But perhaps we should. Plato famously reported, “Heraclitus, I believe, says that all things pass and nothing stays, and comparing existing things to the flow of a river [potamou rhoēi], he says you could not step twice into the same river.”[45] Plato is evidently alluding to Heraclitus’ “river fragment,” fragment 12, which goes like this: On those stepping into rivers staying the same other and other waters flow.
21.5 All Is in Flux
Socrates turns now to the second inspiration for saying that knowledge is perception. According to Heraclitus, he has already pointed out, everything in the sensible world is in constant flux. He and Theodorus remind us that the flux doctrine goes back at least to Homer, and perhaps much earlier, for according to the ancient myths things originate with Oceanus and Tethys, which are flowing streams (see ch. 21.2* above).[39] On the other hand, Socrates points out, Parmenides and his follower Melissus claim that everything is one and unchanging. So
21.4 Knowledge as Perception and Man as the Meature
At this point in the dialogue, we have Theaetetus’ definition of knowledge, that it is sense perception, buttressed by the alleged insight of Protagoras that man is the measure of all things, and by the alleged insight of Heraclitus that everything is in flux. Now Socrates raises some preliminary objections that call into question the definition under consideration. If we accept the fact that man is the measure of all things, Socrates asks, why not say that a pig is the measure of all things? Why not say a
21.3 What Is Knowledge?
The dialogue that constitutes the sequel to the Parmenides is the Theaetetus. It begins with a short introduction in which Euclides of Megara, the philosopher who had hosted the Socratics in a retreat after the death of Socrates (see above, ch. 6.1*), shares with his friend and countryman Terpsion a manuscript in which he recounts a conversation between Socrates and Theaetetus.[23] The young man was a promising student of the mathematician Theodorus and came to be a member of Plato’s Academy.[24] At the time of the reading, Theaetetus has recently