On 11/16/14, we recorded with Jessica Berry (star of our very popular ep. 61) on Pyrrhonian skepticism. Because there are no extant writings by Pyrrho himself (he living shortly after Aristotle around 300 BCE), we read an account of the tradition and practices by a physician from around 200 CE, Sextus Empiricus, called Outlines of Pyrrhonism (aka Outlines of Skepticism), Book I.
What Pyrrhonism is, according to Sextus, is an attitude and a methodology, and it's very much in reaction to the philosophical (proto-scientific) schools present during this era, all of whom made claims that went beyond what was actually observable, e.g. Democritus in claiming that what's really real is not what we perceive but the atoms that make it up, or Platonists in saying that it was really the forms that are real, or especially Stoics in saying all sorts of definite things about God and consequently how we should act.
Sextus is not recommending that we declare all those views false, but that we suspend judgment. He thinks that for any given argument for a positive position, you can come up with (if you try hard enough) an "equipollent" argument for the opposition position. Equipollence means that the two arguments have equal force, but the way Sextus uses the term (i.e. the Greek term that got translated this way) is about a feeling: that you as an individual feels that the two arguments have equal weight.
You might think this is difficult, but Sextus gives us "modes" by which we can come up with arguments for the other side of any argument. For example, someone tells us that "snow is white." Seems pretty uncontroversial, right? But Sextus can reply, "yes, it seems white to you, but what guarantee do you have that snow is white in itself? If you had jaundice, you'd see it as yellow, or if you were an animal we think it would look grey to you. For you to posit your view, or the majority view, as a correct assessment of the objective thing is purely arbitrary.
So these modes (first he gives us ten modes, then five modes, then two modes, relating different ways of presenting the matter among different members of the skeptical tradition) give us many of the famous skeptical arguments used by later thinkers, e.g. "the same oar appears broken when it is in the water and straight when it is out" (seen in Berkeley, who ultimately doesn't come down as a skeptic but rehashes a good deal of Sextus's argument in the course of arriving at his idealism), or the bit about jaundice (which is actually wrong; people with jaundice don't see yellow; their skin looks yellow).
But Sextus woudn't be bothered by the fact that some of the examples he uses are now out of date (he has a whole section about the spontaneous generation of various animals and how their various origins from mud or donkey butts or wherever undoubtedly make them see the world differently. He's not arguing for any positive proposition, but only trying to convince individuals on a view-by-view basis that their assertions are unwarranted. If this sounds like Socrates, yes, Sextus says that some of the dialogues of Plato accord with Pyrrhonism.
So why engage in this effort? Well, the goal is ataraxia, or peaceful contentment, which makes Pyrrhonism fit into the pursuit-of-the-good-life tradition along with those Sextus is criticizing. But, strangely, this isn't supposed to be a passive state where you just give up inquiry; on the contrary, Sextus thinks that only the Pyrrhonians are true inquirers, because they're never satisfied with a particular view.
So what does it mean to not have any positive views, any beliefs? Well, various slanderers of skepticism at the time and throughout the history of philosophy embraced a "rustic" interpretation where it means that the skeptic doesn't even bother to get out of the way of a bus that's about to hit him, because he thinks he can't assert that the bus is actually there. Sextus makes clear that he doesn't have this in mind, and more common among scholars (like Jessica!) is that Pyrrhonians merely withhold assent to matters beyond the everyday, ones that involve metaphysical theories, or (what wasn't any different in the historical period we're talking about) scientific theories. Abandoning this kind of speculation returns us to common sense, to the everyday, to living according to the customs of our time without buying into any pretentious philosopher's crazy-ass theories that, if taken seriously, might well upend our world and send us chasing after some ultimately arbitrary ideal of virtue.
While this sounds like a nice rejoinder to someone preaching at you today that you'd better do X, Y, or Z or end up going to hell, it obviously leaves open a lot of questions: Is there really a sharp distinction between the observable/everyday vs. everything else? What about predictions about the future? What about things that aren't evident, but which science thinks it can legitimately study through empirical, non-arbitrary means? What does this really mean for ethics/behavior? It sounds like we're supposed to be conservative, just going along with whatever society tells us, so can a skeptic have strong political views? Is the notion of ataraxia (which is freedom from disturbance) really compatible with restless, ongoing scientific inquiry (which certainly has an element of disturbance in it)?
I found This collection of Sextus's writings to be replete with helpful introductory and footnoted comments that distinguish Pyrrhonism from other kinds of skepticism and explicitly point out where later philosophers interpreted skepticism incorrectly.
I'd also recommend the Stanford Encyclopedia article on Sextus to get at the different scholarly takes on whether Sextus is recommending we not have any beliefs or not.
Also, if you have $56 dollars to burn or are affiliated with a good academic library that you can order things through, you should Jessica's book Nietzsche and the Ancient Skeptical Tradition.