[MUSIC] We begin with the group of Greek thinkers who have come to be called the Pre-Socratics. These include Thales, Anaximander, Anaximines, Heraclitus, Parmenides, and Anaxagoras. Now don't worry if many of these names are unfamiliar, and even if some of them sound alarmingly alike. I'd like to start by addressing a more pressing problem we face in studying these thinkers. Quite simply, we don't have any of the books that they wrote. The pre-Socratics were active in the 6th and 5th centuries BCE, about two and a half millenia ago. Their writings were well-known and influential in their own day and even in subsequent centuries, but unfortunately these works haven't survived to the present day. Except in quotations and paraphrases from later writers. You'll see, for example, that virtually all of our information about Thales comes from Aristotle, who lived centuries after he did. And for Anaximander and Anaximines], as well as for other pre-Socratics, our sources are even later. An example of such a source is Hyppolytus of Rome, a Christian bishop in the third century CE, about 800 years after Thales, and he wrote a book called The Refutation of all Heresies. Hyppolytus's project in that book was to refute all the pagan philosophy of the Greeks. So he's hardly a fair-minded reporter. But as historians of philosophy, we have to take what we can get in the way of evidence. And Hippolytus may be a hostile source, but he is still a source. He regularly quotes from the philosophers he's trying to refute, and for that I'm eternally grateful. Now if the irony of all ironies, the Refutation ended up being one of the most important vehicles for the preservation and dissemination of the philosophies that he set out to discredit. So go figure that. So before we can begin to study pre-Socratic philosophy, we need to reconstruct these lost works or at least as much of them as we can from reports like those in Aristotle and in Hippolytus. Now in this reconstruction project, we are like archaeologists, who are excavating the ruins of an ancient temple. Little of the original structure is left standing, most of it's fallen down in pieces, many of these pieces have been destroyed or carried away by scavengers or collectors. Some of them may be in the British Museum. Still, archeologists try to reconstruct what the original building was like from the pieces that remain. As well as from reports from people who traveled to the site when it was intact and wrote down a description of what they saw. So that's the sort of reconstruction project that we are engaged in when we investigate the philosophy of the pre-Socratics. Now, the good news is that a lot of this reconstruction project has already been done by classical scholars over the last two centuries. We may call this the recovery phase of the project, in which the surviving pieces of the original building have been gathered together in one location. Those locations are our source books. Now the next step is to reassemble the pieces to reconstruct the original building. Now the bad news is that in the case of pre-Socratic texts, we don't have all the pieces of the original. And in some cases, hardly any of them. So it's a matter of interpretation, hypothesis, and conjecture. To figure out what the whole edifice looked like. That's the exciting project that we will be engaged in. We are going to study these fragmentary remains and partial evidence and try to figure out how they all fit together into a whole. In this case, not a whole building, but a whole text or a whole philosophy.