 Hi, I'm Peter Adamson, and you're listening to the History of Philosophy podcast, brought to you with the support of King's College London and the Leverhulme Trust, online at www.historyoffilosophy.net. Today's episode, The Know-Nothing Party, The Skeptical Academy. Everybody loves a good rivalry. Ali vs. Foreman, the Montagues vs. the Capulets, Gryffindor vs. Slytherin. And the history of philosophy too has its rivalries. Think of Plato vs. the Sophists, the Rationalists vs. the Empiricists, or Nietzsche vs. God. Few philosophical rivalries, though, have been as central to their era as the rivalry between the Stoics and the Skeptics, a dispute which ran for generations from the early Hellenistic period down to the time of the Roman Empire. Julius Caesar set Rome on the path towards empire by assuming the role of dictator in the middle of the first century BC. One of his critics was the great orator, lawyer, and intellectual Cicero. Cicero wrote works on his career, especially during moments of enforced political inactivity, such as the one that resulted from Caesar's ascendancy. When Cicero looked back at the history of philosophy as it had developed since Plato, he saw this dispute between Skeptics and Stoics as one of primary importance, on a par with arguments about the nature of pleasure in the good life and the question of the nature of the gods. He wrote treatises on all of these subjects, devoting a work called the Academica to the topic of skepticism. It is one of our main sources for skepticism in the Hellenistic period. But why would Cicero call a work on skepticism Academica? The answer is simple, if to us surprising. In the generations leading up to Cicero's day, Plato's Academy in Athens had become synonymous with the skeptical approach to philosophy. That certainly would have surprised the first heads of the Academy following Plato's death. As we saw in episode 51, Spusippus and Xenocrates were anything but skeptics. They promoted a bold interpretation of the cosmology and metaphysics of Plato. The next scholarch, or head of the Academy, was a man named Polemo, who shifted things to the terrain of ethics but continued to set forth what he took to be Platonic doctrine. These successors to Plato would probably be broadly happy with the way Plato is usually taught in universities these days. The Platonic dialogues are presumed to contain certain doctrines, and the task of the faithful interpreter is to discover, and perhaps elaborate upon, those doctrines. Then, in about 268 BC, everything changed. The headship of the Academy passed to a philosopher named Arcesilaus. Any doctrine-loving Platonists still frequenting the Academy would have felt like meat lovers whose favorite restaurant is suddenly taken over by militant vegetarians. It was an end to the steady diet of arguments claiming to establish metaphysical and ethical truths. Arguments were certainly still on the menu at Arcesilaus' Academy, but this was, to borrow the ancient phrase, a new Academy, and it had new arguments, arguments that aimed to destroy rather than build theories. This may seem a shocking direction for the Academy to take, but as I mentioned at the end of the last episode, the skeptics could point to Socrates for institutional legitimacy. They could remind us of Socrates' claims of ignorance, and also of the fact that Plato let so many of his dialogues end in a kind of impasse or aporia, where the characters have failed to find the object of their search. Still, it wasn't the doctrinal Platonism of the old Academy, or the suggestions of positive doctrine in Plato himself, that were targeted by Arcesilaus. Rather, his great opponent and rival was Stoicism, or, to make things personal, his contemporary Zeno of Citium, the founder of the Stoic tradition. Their rivalry was continued by the leading successors of both the Stoa and the Academy. On the doctrinal, Stoic side was the great Chrysippus, who was well matched on the skeptical academic side by Carnaides, alluding to the remark that without Chrysippus there would be no Stoa, Carnaides added, and without Chrysippus there would be no me. He was the Muhammad Ali to Chrysippus' George Foreman, and his cherished aim was to deliver a knockout blow to the Stoic's claim that certain knowledge is possible. Skepticism and Stoicism could have been designed specifically as opposing philosophies, and in fact, to a large extent they were. Some of Chrysippus' improvements on Zeno were directly in response to skeptical attack, and the skeptics of the Academy often seemed to have had little more on their minds than undermining the Stoics. This is perhaps just what we'd expect, since the skeptics professed no doctrines of their own. What they brought to the table was not a rival theory, like that of the Epicureans, but an arsenal of dialectical weaponry designed to undercut and cast doubt upon the Stoic position. They were willing to fight on any ground, from logic to physics to ethics, but at the core of the dispute, inevitably, was the nature of knowledge itself. We've been over Stoic epistemology back in episode 60, but since that was a ways back, I should quickly remind you. Zeno, followed by Chrysippus and the other Stoics, claimed to have discovered the criterion of truth, a yardstick by which to sort possibly false beliefs from definitely true beliefs. With such beliefs in hand, we can work our way towards the systematic understanding that the Stoics honor with the name of episteme, knowledge or understanding. For the Stoics, the criterion of truth is what they call a cognitive impression, that is, an impression about how things are that corresponds to how things are, and that cannot be misleading. The Stoics add that a truly wise man will never assent to non-cognitive impressions, though he may accept that some such impressions are more reasonable than others, and act accordingly. For instance, if it seems to the wise man that a tiger is leaping from a nearby tree to attack him, he will not wait to assess the lighting conditions and the possibility of practical jokes, he will just take cover. Still, he will not necessarily form the positive belief that there is a tiger, unless he is satisfied that the impression of the tiger is indeed cognitive. If circumstances leave room for doubt, he will suspend judgment. It's perhaps already clear from this why the Stoics are ideal opponents for the skeptics. For one thing, the Stoics are emphatic that certainty is possible, and they insist that wisdom requires certainty. In this respect, the Epicureans, for instance, would make less satisfying enemies. Epicurus, as we saw, is happy to accept theories, so long as they are not ruled out by our evidence, and so long as they lead to freedom from disturbance. Although he did insist on the truth of all sensations, something the skeptics could enjoy refuting, Epicurus was not really in the absolute certainty game. For another thing, the Stoics themselves deploy the idea of suspending judgment, which happens to be the centerpiece of the skeptical strategy. The Stoics have very high standards for belief. If there is any doubt, they counsel us to suspend judgment and withhold our assent. The Stoics were almost asking for someone to come along and tell them that, according to these standards, no one should ever believe anything. And this, of course, is precisely what Arcesilaus came along and told them. He argued, as we saw when discussing the Stoics, that in principle any impression, no matter how vivid and apparently unproblematic, could be indistinguishable from another impression that leads us into error. The possibility of error may be remote, but if it is present, then the Stoics must admit that the impression in question is not cognitive. This highlights a difference between the skepticism of Arcesilaus and the skepticism we usually encounter in contemporary philosophy. Nowadays, skeptics concentrate on the question of knowledge and wonder whether we can even get to the state where we know something, and perhaps know that we know it. Arcesilaus is applying the brakes at a much earlier stage. He's raising a doubt as to whether we should ever even believe something, never mind take ourselves to know it. This is clearly a much more fundamental skeptical strategy. When Descartes worries that perhaps his beliefs are fed to him by an evil demon, that does not lead him to think that he might need to stop having beliefs. He just worries that the beliefs he has, and will continue having, may not constitute knowledge. Of course, this move on Arcesilaus's part gains most of its plausibility from the stringent requirements that the Stoics have placed on belief. It is the Stoics, not Arcesilaus, who proposed suspending judgment when the criterion of truth is not satisfied. This leads us into the central question about Arcesilaus, one that will also arise with his successor Carnaides. To what extent are their conclusions merely dialectical, that is, merely offered in the context of arguing against the Stoics? And to what extent are they paradoxically beliefs that the skeptics themselves hold? Consider the conclusion of Arcesilaus's argument against Zeno. He shows that the wise man will always suspend judgment, exactly what a skeptic should believe. But hang on, a skeptic shouldn't believe anything, should he? And he certainly shouldn't believe that one should have no beliefs, since that would be a contradiction. Here, the dialectical reading can come to the rescue. On this reading, Arcesilaus is not endorsing the view that no one should ever have beliefs. He's only saying that if we were to adopt the Stoic standard for belief, no one should ever have beliefs. Since he himself would not adopt that Stoic standard, so neither would he be laying down prohibition on belief as a belief he himself holds. Indeed, what Arcesilaus should do, to be consistent, is suspend judgment about whether the Stoic criterion of truth is the right one. In fact, he should also suspend judgment about whether there are indeed cognitive impressions. He's not himself committed on any of these points. He's merely arguing that the Stoics are wrong to commit themselves by defending such ambitious standards for belief and by insisting that there are cognitive impressions, when in fact all these things are unclear. It's a matter of controversy whether this is the right way to understand Arcesilaus. It doesn't help that neither he nor Carnaides wrote any works, leaving us with only indirect evidence as to their oral teaching. But certainly some interpreters, including the greatest ancient skeptic, Sextus Empiricus, did not adopt the dialectical reading. He, in effect, accused the new academy of dogmatism, that is, of holding a commitment or doctrine. This is the meaning of the Greek word dogma, often used in the context of political decisions or later tenets of theology. Of course, Arcesilaus would be a dogmatist of an unusual sort, a negative dogmatist, whose doctrine is precisely that one should have no doctrines. But this was still enough to damn him in the eyes of Sextus for being insufficiently skeptical. A thoroughgoing skepticism would be skeptical even regarding the question of whether one can have knowledge, and the question of whether one should have beliefs. Of course, that is a difficult position to understand, and we'll have to do some work to wrap our minds around it when we get to Sextus. For now, though, let's look at another problem faced by Arcesilaus aside from this charge of self-refutation and negative dogmatism. This is the so-called apraxia, or inactivity, objection. According to the objection, the skeptic cannot do anything at all if he lacks beliefs. Consider, for instance, the action of going to the zoo to see the giraffes. To leave the house, get on environmentally friendly public transport, and reach the giraffes will require a whole series of beliefs, for instance, that this bus does go to the zoo, that the map does show the location of the giraffe enclosure, and so on. An utter lack of belief seems to doom us to an utter lack of visits to see the giraffes, a prospect none of us would wish to contemplate. And the same argument goes, of course, for any action you care to name. Arcesilaus dealt with the objection by once again exploiting weapons unwittingly placed into his hands by the Stoics. As we saw with the attacking tiger example, the Stoics think that the sage will on occasion follow impressions which strike him as reasonable, without necessarily giving these impressions his full assent. Now Arcesilaus himself can pounce, and say that what goes for attacking tigers will work just as well for visiting giraffes. The skeptic will take certain things as reasonable, and this will be enough to allow him to act, without ever forming settled beliefs. This response is typical of Arcesilaus, in that it works within the Stoic system he is attacking. Again, it is hard to tell whether he's being dialectical, or giving us his own position. Notice though that if it is his own position, it would give him an escape to the previous problem about self-refutation. He can say that he does not actually believe that one should never form beliefs. He's actually not sure about this. Still, given the arguments that undermine any possible criterion of truth, it does strike him as reasonable that one should never form beliefs, so he never does. Now, I know what you're thinking. What exactly is the difference between believing something and taking it to be reasonable? Of course, that's a problem for Zeno's Stoics, too, but it seems more pressing for Arcesilaus than for Zeno, since his whole stance is now turning on this distinction. So it's no surprise that the next head of the skeptical academy, Carnaides, devoted considerable attention to this question of how the skeptics' actions are guided. Using different terminology, he said that certain impressions strike us as pithanon. The word means persuasive or plausible. Like Arcesilaus, he suggests that these impressions will be used as a practical guide by the skeptic. But he went further, observing that the standards we use will differ depending on how high the stakes are. In the normal course of affairs, one bit of evidence will suffice. For instance, if I'm looking for the giraffes, I'll just ask another zoo visitor and follow their directions. But what if it is really important if, say, I need to be at the giraffe enclosure in five minutes to pay a ransom to the giraffe nappers who are demanding one million dollars for the safe return of Hiawatha? Then I will want to make extra sure. Similarly, Carnaides suggests that our caution will vary in accordance with the importance of the matter at hand, and that in really crucial situations, I will not, for instance, merely look several times, but also consider the lighting conditions, whether anyone might be trying to deceive me, and so on. In short, when the chips are down, I'll do all the things the stoic sage would do to make sure he's having a cognitive impression. Only when these tests are passed will I pronounce myself persuaded. But the arguments against the stoic position are still taken as decisive, so even in these circumstances I will not take myself to be certain. I will not delude myself into believing that my impressions really are cognitive, meaning that they could not possibly be false. There is always room for doubt. Carnaides presents us with a conundrum. On the one hand, there is this Carnaides I've just been describing, who seems happy to allow us to take ourselves to be pretty sure about things for all intents and purposes, even if the stoic criterion of truth remains unsatisfied. On the other hand, there is the Carnaides who showed up in Rome during the embassy of philosophers in 155 BC, as mentioned by David Sedley in my interview with him. On that occasion, Carnaides scandalized his audience by arguing in favor of justice, and then on the next day arguing just as persuasively against everything he'd said in the first speech. This kind of logical, scorched-earth campaign hadn't been seen since the days of the sophists. That sound you hear might be Plato slapping his forehead with disbelief, as a head of his academy shows that it is possible to argue with equal plausibility on both sides of the most important issues we face. On the other hand, as I've said, Socrates too was pretty good at arguing people to a standstill. The real question is what Carnaides wanted the audience to learn from his display. Even the most intimate associates of Carnaides already felt the difficulty of determining his exact view. His follower, Cleitomachus, who took over as scholar of the academy in 127 BC, set forth a dialectical reading like the one we considered for Arcesilaus. Cleitomachus frankly admitted that Carnaides was impossible to understand fully. This was intended not as a criticism, but as an expression of his admiration for Carnaides, whose skepticism was of a depth that simply could not be fathomed. Nonetheless, he was confident that Carnaides was a thoroughgoing skeptic who argued for global suspension of belief, and who presented his practical criterion of plausibility only within the context of disputing with the Stoics. But other followers of Carnaides, who had also studied at the feet of the master, disagreed. For them, Carnaides had indeed been suggesting that we can allow ourselves belief of a sort, assenting to impressions which strike us as plausible, while of course stressing that this kind of belief is always fallible. The leading proponent of this reading was another student of Carnaides, Philo of Larissa. For some skeptics, Philo's stance was all too moderate. To mark the difference between the hard-headed skepticism that dispensed with all belief, and the half-hearted skepticism light of Philo, they took up a new figurehead. This new figurehead was also the oldest figurehead available, Pyro. Returning to this earliest of the skeptics, they rejected the skeptical academy as a fall from grace, and initiated the last phase of ancient skepticism, calling it pyranism. It was this form of skepticism that was embraced by Sextus Empiricus in the 2nd century AD. He will finally supply us with a leading skeptic who wrote extensively, and whose writings are preserved to this day. The subtle defense Sextus provides for the non-doctrine of Pyrronian skepticism ranks among the great achievements of later ancient philosophy, and we'll be discussing it in a few episodes. But first, we need to stay in the 1st century BC, and with Philo of Larissa. His importance is to some extent a function of geography. Carnaides had visited Rome, but Philo of Larissa actually moved there. He made a huge impression, not least on Cicero, whose own fairly mild-mannered brand of academic skepticism is derived chiefly from encountering Philo. Cicero also details for us one more heated rivalry between Philo and his student Antiochus. Both of them claimed to be members of the academy, but Antiochus broke with the new academy and embraced dogmatism, setting out a kind of grand synthesis which found common ground between the Stoics, Plato, and even Aristotle. Antiochus was displeased when Philo, newly arrived in Rome, published books setting out his moderate skepticism. His rebuttal of those books constituted nothing less than a contest for the soul of the academy. It was these contentious events that set the stage for Cicero's composition of the academica, which, as I have said, is only one of numerous Ciceroian works indispensable to our understanding of Hellenistic philosophy. And, of course, it's fascinating to see Cicero, a famous player on the stage of Roman politics, turn his hand to philosophy. But does Cicero have anything to offer the historian of philosophy, apart from his famous name and a wealth of otherwise lost information? For our podcast, this question is anything but academic, so we'll try to answer it next time, on The History of Philosophy, without any gaps.