If you’ve read some about ancient Pyrrhonism you may have encountered the term “neo-Pyrrhonism” and the idea that the Pyrrhonism handed down to us does not really come from Pyrrho, but instead Aenesidemus is its founder - an idea that Wikipedia presents as a fact, despite the case that the matter is easily be found to be disputed. (That Wikipedia has become unreliable and biased is now a well-worn trope. Even Wikipedia’s co-founder, Larry Sanger, has said it can no longer be trusted. Its fundraising efforts have also been shown to be a scam.)

As a practitioner of Pyrrhonism and a deep reader of all of the surviving ancient texts about Pyrrhonism, it has for long struck me that this belief had to be incorrect and that someone should get around to thoroughly debunking it. I was delighted to encounter Evan O'Donnell’s new article in Ancient Philosophy “Aenesidemus Was Not an Academic” that does this debunking beautifully.

For me, the main evidence that it was incorrect comes from Sextus Empiricus. At many points in his works, Sextus quotes Timon. (Timon was the one who recorded Pyrrho’s thought, like Plato was the one who recorded Socrates’ thought. Unfortunately, Timon’s works have not come down to us except in fragments quoted by others.) Sextus never disagrees with Timon, but he frequently feels he needs to explain what Timon meant. His respect for Timon is noteworthy given how differently the two men expressed themselves. Sextus wrote in a cautious, lawyerly fashion. Timon wrote exuberantly, making strong claims. In contrast, when Sextus cites Aenesidemus, he sometimes does so to disagree with him. At other times, he holds Aenesidemus at a distance. He never does this with Timon. He always embraces Timon.

Both Sextus and Diogenes Laertius (our next-best source on ancient Pyrrhonism) act like they are familiar with Timon’s works and they remained available. If what Aenesidemus said was so different from what Timon said, wouldn’t that be noteworthy for both Sextus and Diogenes?

One of the weaknesses of Diogenes’ reports is that he uncritically passes on stories that discredit the philosophers he is writing about, many of which are obviously implausible. If Aenesidemus were somehow the real founder of Pyrrhonism, one would think there would be a story about it that Diogenes would report, as it would discredit Pyrrho. Diogenes reports no such story. Instead, he provides a pedigree of the heads of the Pyrrhonist school and mentions some prominent Pyrrhonist thinkers. Aenesidemus is there in the middle of it.

For some reason, some scholars have chosen to reject this pedigree - Diogenes is, after all, not all that reliable, and even he points out that there are some disputes about the accuracy of parts of the lineage (but not the parts around Aenesidemus).

Instead, they have fixated on a brief comment in our third-best source on ancient Pyrrhonism, a summary of Aenesidemus’ influential work, Pyrrhonian Discourses, written in the 10th century by Photius, a Byzantine Bishop. Photius summarized many ancient books. Some have come down to us; some have not. Based on the ones that survived, we know he generally gave pretty accurate descriptions of what he had read. About Pyrrhonian Discourses, he says one key thing that has caused people to infer that Aenesidemus was the real founder of Pyrrhonism:

In writing the discourses, Aenesidemus addresses them to Lucius Tubero, one of his colleagues from the Academy, a Roman by birth, with an illustrious ancestry and a distinguished political career. (Long and Sedley translation - and to my knowledge, the only translation that has been published.)

From this, it has been concluded that Aenesidemus had been a member of the Academy. As we have a good idea of when Lucius Tubero lived - he was a friend of Cicero and married to Cicero’s cousin Visellia - we know that Aenesidemus was active at a critical time for the Academy - the era when the skeptical Academy collapsed from internal dissension. Photius further tells us that this was one of the topics Aenesidemus addressed. The Academics were no longer skeptics, like the Pyrrhonists, but, as Aenesidemus put it, “Stoics arguing with Stoics.”

From this, a tidy story can be inferred. Aenesidemus was a member of the Academy during the era when it was in disintegration. In order to preserve philosophical skepticism and to lend credibility to what was really a new school of philosophy he had dreamed up - a modification to Academic Skepticism - he referred back three hundred years to Pyrrho to serve as a figurehead for his new philosophical movement arising from the ruins of the skeptical Academy. Hence, the philosophy passed down to us from Aenesidemus and Sextus Empiricus and Diogenes Laeritus should rightly be called “neo-Pyrrhonism” to distinguish it from the original, rather different, and thoroughly defunct Pyrrhonism of Pyrrho.

As we have only fragments from Timon, we don’t know many details of Pyrrho’s Pyrrhonism, but we do have a summary of it handed down to us by the early Christian writer Eusebius, quoting the Aristotelian philosopher Aristocles, quoting Timon, quoting Pyrrho - but with a good chance that Aristocles was quoting Aenesidemus, because Eusebius’ quote includes a comment on the quote from Aenesidemus. This is the famous bit of text known as the “Aristocles Passage,” in which Christopher Beckwith identified that Pyrrho had repurposed the Buddhist Three Marks of Existence as a basis for his philosophy. It has since been identified that Pyrrho also repurposed another bit of Buddhism: the Antidotes to the Three Poisons.

The Aristocles Passage presents a philosophical conundrum. In it, Pyrrho appears to be making a firm, negative statement about metaphysics (a la the Three Marks of Existence) or epistemology, or, perhaps, psychology. It’s the kind of firm, negative belief that Sextus Empiricus would clearly classify as an example of the kind of negative dogmatism that Pyrrhonists eschew. Therefore, Sextus’ Pyrrhonism and Pyrrho’s Pyrrhonism would appear to be two different philosophies. This difference lends credibility to the idea that the Pyrrhonism we have from every writer since Aenesidemus is from a philosophy created by Aenesidemus that he marketed under Pyrrho’s name.

This makes a tidy and persuasive story. The human mind is a story-generating device. We are magnetically attracted to nice-sounding stories that seem to solve certain problems for us. We are easily convinced by them, even when they don’t fit the facts very well. For example, how was it that Eusebius’ quote from Pyrrho summarizing Pyrrhonism also references a seemingly approving comment from Aenesidemus about that quote if Pyrrhonism is Aenesidemus’ invention? How is it that no one ever mentions that Aenesidemus is the real founder? Isn’t that sort of scandalous? How is it that Sextus so often cites Timon if Timon’s Pyrrhonism is so different from that of Sextus?

Like so many issues in understanding what the ancient Greeks actually meant, much depends on the translation of a single word that has, in turn, created this false but cleverly persuasive story about Aenesidemus. That word is συναιρεσιώτῃ. It’s the word that causes Long and Sedley to say that Lucius Tubero is one of Aenesidemus’s “colleagues from the Academy.” Evan O’Donnell makes a compelling case that this is not only a flawed translation, but a correct translation reveals that the clever story is false. There was no neo-Pyrrhonism invented by Anesidemus. There was just one Pyrrhonist tradition in antiquity (not that it didn’t evolve over the centuries, and not that individual Pyrrhonists didn’t have their own interpretations).

The word συναιρεσιώτῃ is not a common one, but it is formed with common parts, a prefix, a suffix, and a root. The prefix and suffix are clear enough from other usages to point to “co-αιρεσις member.” That leaves the root, αιρεσις. What does that mean? The usual translation is “heresy,” but “sect” or “faction” are also meant, and in the case of philosophy, “school.”

Why would Photius say this if Aenesidemus was a Pyrrhonist and Lucius Tubero was an Academic, and thus not members of the same school?

O’Donnell gives us a clear answer. It’s because Photius is a Christian Bishop writing a thousand years after Aenesidemus, when Pyrrhonism, Academic Skepticism, and all of the other great philosophies of antiquity were long since dead. Photius’ understanding of these ancient schools is thin and distorted. Photius also summarized some other books that briefly discussed Pyrrhonism and Academic Skepticism. Those books lumped them together, making no distinctions between them.

Even now it’s common to encounter modern discussions of the ancient skeptics in which the writers lump the Pyrrhonists together with the Academics and treat them as nearly indistinguishable members of the same philosophical movement. Why should we expect Photius to take more care than they do?

Further, Photius used συναιρεσιώτῃ a couple of other times in his writings. In both instances, he was clearly referring to members of a heresy. Would it not seem obvious that any well-educated 10th-century member of the Christian faith would understand any form of ancient philosophical skepticism as a heresy?

In light of what Evan O’Donnell has made clear, the dispute seems likely to be over. There was no ancient neo-Pyrrhonism invented by Aenesidemus. Pyrrho is the founder of Pyrrhonism.

If you’re interested in more detail, O’Donnell’s paper can be accessed from his website.