The Pyrrhonian Skeptics

In about 100 BCE, the Academy broke into rival factions.

Aenesidemus (1st century BCE) led one of these factions. He was one of the Academics who thought the school had lost its way. In an attempt to return to what he thought of as the skepticism that was lost under Philo, Aenesidemus founded a breakaway skeptical movement under the name of Pyrrho.

"[Our school is called] Pyrrhonian from the fact that Pyrrho appears to us to have applied himself to Skepticism more thoroughly and more conspicuously than his predecessors. (Outlines of Pyrrhonism I.7).

In a list of Empiricist physicians, Diogenes Laertius mentions "Sextus the Empiricist" (Lives of the Philosophers IX.116).

Sextus Empiricus says that he himself wrote a (now lost) set of discourses on Empiricism (Against the Grammarians III.61).
This movement is Pyrrhonian Skepticism. Our knowledge of this movement depends primarily on the much later description in Sextus Empiricus (second or third century CE physician and philosopher).

The Pyrrhonian Skeptics were the first to call themselves "skeptics" (σκεπτικοί).

Empiricism and Rationalism

Sextus Empiricus takes his name from the Empiricist medical tradition in which he worked.

By the second century CE, the dispute about knowledge in medicine was developed enough that Galen (130-210 CE) could identify "empiricists" (ἐμπειρικοί) and "rationalists" (λογικοί).

"Those who rely on experience only are accordingly called empiricists. Similarly, those who rely on reason are called rationalists. And these are the two primary sects in medicine. The one proceeds by experience to the discovery of medicines, the other by means of indication. And thus they named their sects empiricist and rationalist. But they also customarily call the empiricist sect observational and relying on memory and the rationalist sect dogmatic and analogistic" Galen, 129-216 CE. Most famous doctor of later antiquity

Galen, Three Treatises On the Nature of Science. On the Sects for Beginners, An Outline of Empiricism, On Medical Experience. Translated by Richard Walzer and Micheal Frede. Hacket Publishing Company, 1985).
(Galen, On the Sects for Beginners I.65, 1985: 3).

These understandings of knowledge in medicine were part of an attempt by the doctors to explain how they know what they were doing and thus both to justify their claim to expertise and to push the field forward. The doctors needed to do this to distinguish their art from the everyday practices that could to be some extent handle fractures, dislocations, and small wounds, but was otherwise mostly powerless to take on the problems people faced.

Rationalism in Plato and Aristotle

We might be tempted to think that empiricism has to be the right understanding of knowledge in medicine, but this had not been the dominate view in the philosophical tradition. Plato, for example, in the Laws, has the Athenian talk about empiricist physicians as second in a certain way to rationalist physicians.

"There are men that are doctors, we say, and others that are doctors' assistants; but we call the latter also, to be sure, by the name of doctors. These, whether they be free-born or slaves, acquire their art under the direction of their masters, by observation and practice and not by the study of nature—which is the way in which the free-born doctors have learnt the art themselves and in which they instruct their own disciples" (Laws IV.720a).

To understand Plato's rationalism, we need to think about how he understands expertise and its relation to experience. It will help too to see how Aristotle develops the position he sees in Plato.

Experience and Knowledge in Plato

In the Gorgias, Plato makes Socrates that an "art" cannot be completely a matter of experience. He thinks that "cookery," for example, is nothing more than a collection of routines that have been discovered by observation and memory of what usually happens. He thinks these cognitive processes do not involve reason.

"Rhetoric seems to me to be a pursuit that is not a matter of art, but belongs to a soul given to make guesses, that is bold, and that has a natural bent for clever dealing with mankind, and I sum up its substance in the name flattery. This practice, as I view it, has many branches, and one of them is cookery; which appears indeed to be an art but, by my account of it, is not an art but experience and routine (ἐμπειρία καὶ τριβή). I call rhetoric another branch of it..." (Gorgias 463a). "I was saying, Callicles, that cookery seems to me not an art but experience, unlike medicine, which, I argued, is an art. It has investigated the nature of the object it serves the cause of what it does, and has some account to give of each of these things. The other, the one concerned with pleasure, to which the whole of its service is entirely devoted, proceeds toward its object quite inexpertly, without having investigated at all the nature of pleasure or its cause. It does so altogether irrationally (ἀλόγως)--with no discrimination, relying on routine and experience for merely preserving a memory of what customarily happens; and that is how it supplies its pleasures" (Gorgias 500e).

Plato was aware of a tradition of thinking about expertise that accepted the view he makes Socrates reject in this passage from the Gorgias. In the Phaedo, the character says that when he was young, he was interested in the question whether knowledge has its basis in anything more than observation and memory.

The view about the brain Socrates is wondering about seems to go back to Alcmaeon of Croton (6th century BCE). He was part of the Ancient medical tradition that was interested in the nature of knowledge to get clear on the claim of medicine to be a real "art" (τέχνη).

"For reasoning is a kind of memory combined with things apprehended with the senses" (Hippocrates of Cos (5th century BCE), Precepts 1).
"When I was young, Cebes, I was tremendously eager for the kind of wisdom which they call the inquiry into nature. I thought it was a glorious thing to know the causes of everything, why each thing comes into being and why it perishes and why it exists; Do heat and cold, by a sort of fermentation, bring about the organization of animals, as some people say? Is the blood, or air, or fire by which we think? Or is it none of these, and does the brain furnish the sensations of hearing and sight and smell, and do memory and opinion arise from these, and does knowledge come from memory and opinion in a state of rest" (Phaedo 96b).

Plato makes Socrates go on to argue that the reality of things is something we can only grasp by reason.

   "Is the reality itself (αὐτὴ ἡ οὐσία), whose reality we give an account in our dialectic process of question and answer, always the same or is it liable to change? Does the equal itself, the beautiful itself, what each thing itself is, the reality, ever admit of any change whatsoever? Or does what each of them is, being uniform and existing by itself, remain the same and never in any way admit of any change?
   It must necessarily remain the same, Socrates.
   But how about the many things, for example, men, or horses, or cloaks, or any other such things, which bear the same names as those objects and are called beautiful or equal or the like? Are they always the same? Or are they, in direct opposition to those others, constantly changing in themselves, unlike each other, and, so to speak, never the same?
   The latter, they are never the same.
   And you can see these and touch them and perceive them by the other senses, whereas the things which are always the same can be grasped only by the reasoning of the intellect (τῷ τῆς διανοίας λογισμῷ), and are invisible and not to be seen?
   Certainly that is true.
   Now, shall we assume two kinds of existences, one visible, the other invisible?
   Let us assume them, Socrates" (Phaedo 78c).

It is reason we need for knowledge. This seems to be the import of the following passage in the Republic.

   "On the one side are those you spoke of just now, the sight lovers, craft lovers and practical people, and on the other side those about whom we are giving an account, which people alone someone would rightly call philosophers.
   How do you mean, Socrates?
The lovers of sights and sounds anywhere embrace beautiful sounds and colors and shapes and all things crafted out of them, but their thought is unable to see and embrace the nature of the beautiful itself.
   Certainly.
   Indeed, those who are able to reach the beautiful itself and see it of itself won’t then be many, right?
   Right.
   Then the one who believes in beautiful things but neither believes in the beautiful itself nor, if someone should lead him to awareness of it, is able to follow, does he seem to you to be living awake or asleep? But consider whether dreaming isn’t this: whether asleep or awake, to take a likeness to be what is not a likeness but that thing itself that it resembles.
   I certainly think such a person appears to be dreaming.
   But what about the one who, being the opposite of these, takes the beautiful itself to be something and can see clearly both it and those things participating in it, and neither believes the things that participate are it nor that it is the things that participate in it—now again, does this person seem to you to be living awake or dreaming?
   He is very much awake.
   So would it be right to say that his thought is knowledge, since he knows, but the other one’s thought opinion because he opines?
   By all means, Socrates" (Republic V.476a).

The point is not that we don't ordinarily use the term knowledge to describe what distinguishes people with experience from those who lack it. We say, for example, that a good cook has knowledge that those of us without the experience lack. When we say these things, though, we are not attributing to the cook the cognitive state Plato understands as knowledge. We are using knowledge for a kind of belief those without the experience lack, but Plato thinks that this belief is not knowledge. The belief might be true. It might be too that to justify the belief, the cook can point to his experience and the experience of other cooks. Still, as Plato sees things, the cook whose skill is completely a matter of experience has not exercised reason to grasp the underlying reality. This cook does not have a theory in terms of things we do not observe that explains why doing certain the things results in foods that taste a certain way. He "knows" what to do, but this ability he possesses has its basis solely in experience.

Experience and Knowledge in Aristotle

Aristotle follows Plato on this point. In epistemology, he is a rationalist about knowledge.

One place we can see this is at the outset of the Metaphysics. In this passage, Aristotle illustrates the difference between experience and knowledge in terms of the two kinds doctors Plato discusses in the Laws.

"By nature all men reach for knowledge. ... Animals are by nature born with the power of perception, and from this some acquire the faculty of memory, whereas others do not. ... The other animals [the nonhuman animals] live by impressions and memories, and have but [comparatively speaking] a small share of experience; but the human race lives also by art and reasoning. It is from memory that men acquire experience, because the numerous memories of the same thing eventually produce the effect of a single experience. Experience seems very similar to knowledge and art, but actually it is through experience that men acquire knowledge and art. ... Art is produced when from many thoughts from experience a single universal (καθόλου) judgment is formed with regard to like objects. To have a judgement that when Callias was suffering from this or that disease this or that benefited him, and similarly with Socrates and various other individuals, is a matter of experience; but to judge that it benefits all persons of a certain form, considered as a class, who suffer from this or that disease (for example, the phlegmatic or bilious when suffering from burning fever) is a matter of art" (Metaphysics I.980a).

The medical practitioner has thinking whose basis is in experience. He can make the "judgement that when Callias was suffering from this or that disease this or that benefited him, and similarly with Socrates and various other individuals" because he has lots of experience with the disease and its treatment.

The medical theorist has a more advanced thinking. Unlike the practitioner, the theorist can make the more sophisticated judgment that "it benefits all persons of a certain type, considered as a class, who suffer from this or that disease (for example, the phlegmatic or bilious when suffering from burning fever)."

This more sophisticated judgment involves a grasp of a universal. Although the practitioner can make a diagnosis in circumstances in which the layman is more likely to make a mistake, he does not grasp the universal the theorist knows is common to the patients who have a certain disease and benefit from a certain treatment. The practitioner does not conceive of the disease in terms of a universal, such as being phlegmatic. He notices the disease in terms of how his patients look, and he acquired this ability on the basis of his experience in seeing patients with the disease. This ability is a matter of perception and memory, not the cognition Aristotle understands as reason.

"When people are questioned, if you put the questions well, they answer correctly of themselves about everything; and yet if they had not within them some knowledge and right reason, they could not do this (Phaedo 73a).

  "We say there is such a thing as to be equal. I do not mean one piece of wood equal to another, or one stone to another, or anything of that sort, but something beyond that--the equal itself (αὐτὸ τὸ ἴσον). Shall we say there is such a thing, or not?
  We shall say that there is most decidedly, Socrates.
  And do we know it, the thing that is?
  Certainly.
  Whence did we come upon the knowledge of it? Was it not from the things we were just speaking of, by seeing equal pieces of wood or stones or other things, on the occasion of them that equal was in thought, it being different from them? ... It is on the occasion of those equals, different as they are from that equal, that you have thought and come upon knowledge of it?
  That is perfectly true" (Phaedo 74a).

  "Then before we began to see or hear or use the other senses we must somewhere have gained a knowledge of the equal itself, if we were to compare with it the equals which we perceive by the senses, and see that all such things yearn to be like the equal itself but fall short of it.
  That follows necessarily from what we have said before, Socrates.
  And we saw and heard and had the other senses as soon as we were born?
  Certainly.
  But, we say, we must have acquired a knowledge of equality before we had these senses?
  Yes.
  Then it appears that we must have acquired it before we were born.
  It does.
  Now if we had acquired that knowledge before we were born, and were born with it, we knew before we were born and at the moment of birth not only the equal and the greater and the less, but all things such as these? For our present argument is no more concerned with the equal than with the beautiful itself and the good and the just and the holy, and, in short, with all those things which we stamp with the thing itself that is in our dialectic process of questions and answers; so that we must necessarily have acquired knowledge of all these before our birth.
  That is true, Socrates" (Phaedo 75b).
Aristotle, however, unlike Plato, does not think that reason is inborn. He thinks it is a power human beings naturally acquire as they become adults. This is his point in an important passage in the Posterior Analytics.

"All animals have a discriminatory power, called perception. In some retention of the perception comes about, but in others not. ... When this happens many times, a difference comes about, so that some come to have reason from the retention, and others not. From perception comes memory, and from memory (when it occurs often in connection with the same thing), experience; for memories many in number form a single experience. From experience, from the whole universal that has come to rest in the soul (the one apart from the many, whatever is one and the same in all those things), there comes a starting-point of art and of knowledge, of art if it deals with coming to be and of knowledge if it deals with being. Thus the states [that grasp starting-points] neither belong in us in a determinate form, nor come about from other states that are more cognitive; but they come about in us from perception—as in a battle when a rout occurs, if one man makes a stand another does and then another, until a starting-point is reached. The soul is such as to be capable of undergoing this. ... So it is clear that it is necessary to cognize the firsts by induction; for perception instills the universal in this way" (Posterior Analytics II.19.99b).

Aristotle thinks perception is the first step in the casual process that results in reason in human beings. He thinks that all animals have the power of perception and the power to act in terms of these perceptions. Some animals, as they mature, develop the ability to remember what they perceive. From these memories, some develop what Aristotle calls experience. This allows them to react to their perceptions in a more nuanced way. From experience, humans develop what Aristotle understands as reason and the knowledge that belongs to it.

It is easy for us to misunderstand Aristotle because we find it natural to think experience can function as evidence for knowledge. This is not how experience functions in the causal process Aristotle thinks results in reason.

An example can help make this a little clearer.

Suppose in a geometry class we are given a proof that the interior angles of a triangle sum to two right angles. The premises in the proof function as evidence for the conclusion, but these premises do not say anything about the experiences of looking at or touching toy triangles we might have had in school as children. So the proof does not cite these, or any experiences we might have had, as evidence for the truth of the conclusion.

It might be, though, that such experiences are necessary for us to understand the proof because it might be that without these experiences, we would not possess the concepts the premises of the proof are about.

We can describe this difference by saying that although the experiences we had as children do not function as evidence for the knowledge the proof gives us, these experiences enable us to have this knowledge.

In the causal process Aristotle describes, what he calls experience enables us to have reason and its knowledge. It is not evidence for this knowledge. He does not think we get this knowledge by drawing conclusions from our experience. He thinks that drawing conclusions is possible only once we have reason and its knowledge.

A Reaction Against Rationalism

The empiricist tradition arises as a reaction to this rationalism about knowledge.

The underlying idea in the empiricist tradition is the one we already saw in the Phaedo where Socrates, as Plato represents him, is talking about his early interest in what was called the inquiry into nature. One of the views he considered is that "the brain furnish the sensations of hearing and sight and smell, and do memory and opinion arise from these, and does knowledge come from memory and opinion in a state of rest."

With one important difference, this view is like the one we saw in Aristotle. Unlike the view Socrates considered, Aristotle thinks that human beings acquire reason from their experience in a causal process that naturally occurs as they mature from children into adults. Further, Aristotle follows Plato in thinking that knowledge is an achievement of reason and thus that observation and memory alone are not enough for knowledge.

The empiricists questioned whether we need to recognize the power of mind Plato and Aristotle call reason.

The following example helps make the issue a little clearer.

Suppose that all human beings we and others have known have always been mortal. Is this enough for us to know that all human beings are mortal? It would not be for Aristotle because he thinks that knowledge requires that we grasp the universals that make it necessary for every human being to be mortal.

Against this rationalist conception of knowledge, we might think that we gain nothing by positing a power of mind to grasp relations of consequence and incompatibility. We might think we can account for our knowledge that all human beings are mortal in terms of our sense experiences and our memory of them.

In this empiricist approach to knowledge, the experiences we retain in memory produce certain beliefs. So, when the human beings of which we have had experience (either directly ourselves or through the reports of others who had experiences of them) turn out to be mortal, our memory produces in us the belief that all human beings are mortal. Further, because of how we form this belief, it counts as knowledge if it is true.

In thinking about this dispute between the empiricists and the rationalists, it is important to see that the dispute is over the power of mind Plato and Aristotle call reason and think gives us knowledge of an underlying reality we cannot experience. The empiricists deny that human beings have this power of mind.

Pyrrhonian Skepticism

The history of Pyrrhonian Skepticism is uncertain, but there seems to have been a connection to Empiricism.

Pyrrho of Elis, 4th to 3rd century BCE

Timon of Phlius


Menodotus of Nicomedia


"It seems to me that the early Empiricists clearly were not Pyrrhonists, if by Pyrrhonism we mean the kind of position espoused by Aenesidemus in the first century B.C. and later authors like Sextus Empiricus. For the early Empiricists seem to simply espouse a dogmatic extreme skepticism concerning reason" (Frede, "The Ancient Empiricists," 248).

"Empiricism became radically transformed under the growing influence of Pyrrhonism in the Empirical school of medicine. It is difficult to state when this transformation started. If it is true, as is usually assumed, that the famous Empiricist physician Heraclides of Tarentum is identical with the teacher of the philosopher Aenesidemus, who gave Pyrrhonean skepticism its detailed form, the process may have started as early as 100 B.C. with Heraclides of Tarentum. It certainly was in full progress in the second century A.D., when the main representatives of the Empirical school of medicine, Menodotus, Theodas, and Sextus Empiricus, at the same time were the main representatives of Pyrrhonean skepticism" (Frede, "The Ancient Empiricists," 251-252).

"It is necessary to suppose that there is some power in us which is able to consider and judge what is incompatible and what follows [because if] there is no such power in us, we should not endeavour either to produce arguments ourselves or to refute those arguments which have been badly argued. But if indeed there is some power in our soul, as Heraclides of Tarentum and some other mem who called themselves empiricists believe..." (Galen, "An Outline of Empiricism," 44).

"The way Galen puts the matter... is somewhat prejudicial, since we may doubt that Heraclides meant to posit a power in the soul. But even apart from this, Galen's language suggests that Heraclides' position in this respect constituted a departure from from traditional empiricism" (Frede, "An empiricist view of knowledge: memorism," 250).

"An empiricist view of knowledge: memorism," 225-250. In Epistemology: Companions in Ancient Thought 1, edited by Stephen Everson. Cambridge University Press, 1990).

"The Pyrrhonean position is the following: it seems that we just cannot help the fact that certain things appear to us to be the case and that we thus, with more or less confidence, take them to be the case. This just seems to be a fact of human life. Similarly, it just seems to be a fact that often the question arises whether what appears to be the case actually is the case and that hence we give the matter further consideration. It may, e.g., be of considerable importance to us whether our impression is correct, and yet our confidence in our impression may be very low. In such a situation, we may well be driven to give the matter further consideration. Now there are two ways in which we might give the matter further consideration. We might treat the question whether what appears to be the case actually is the case as an ordinary question to be settled by ordinary means, i.e., by the procedures we use in ordinary life to settle such questions, e.g., by having another look, by reading up on it, by asking other people, by consulting experts, etc. There is a whole array of such procedures which, as a matter of fact, people ordinar[i]ly follow. And ordinarily they follow such procedures until they feel sufficiently confident that their impression is correct. And what degree of confidence they are satisfied by depends, among other things, on the importance they attach to the matter. Thus, as a matter of fact, there seems to be a whole pattern of cognitive behavior that people ordinarily follow and that we could study by merely observing what people do. Experience suggests that following these procedures is conducive to life; hence, following them is a matter of life- experience. And this, presumably, is why people ordinarily follow these procedures" (Frede, "The Ancient Empiricists," 253-254).
"Menodotus maintains that [Timon] had no successor, and that the school lapsed until Ptolemy of Cyrene reestablished it. Hippobotus and Sotio, by contrast, report that Timon taught Dioscurides of Cyprus, Nicolochus of Rhodes, Euphranor of Seleucia, and Praylus of Troad. ... Ephranor taught Eubulus of Alexandria; Eubulus taught Ptolemy, and he taught Sarpedon and Heraclides; Heraclides taught Aenesidemus of Cnossus, the compiler of eight books of Pyrrhonean discourses; Anesidemus taught Zeuxippus of Polis; Zeuxippus taught Zeuxis of the angular foot; Zeuxis taught Antiochus of Laodicea-upon-the-Lycus; Antiochus taught Menodotus of Nicomedia, an Empiricist physician, and Theodas of Laodicea; Menodotus taught Herodotus of Tarsus, son of Areius, and Herodotus taught Sextus the Empiricist, who wrote ten books on Skepticism, and other fine works. Sextus taught Saturninus who is contemporary with us, himself an Empiricist” (Lives of the Philosophers IX.115).

The Heraclides on this list who Diogenes Laertius says taught Anenesidemus may be Haraclides of Tarentum (1st century BCE, a generation before Aenesidemus). He was an Empiricist doctor.

One way to understand this is to suppose that Pyrrhonian Skepticism has two main parts. It consists in their view of how we are permitted to form beliefs and in the dialectic they direct at their opponents. This first part seems to have its roots in Carneades's discussion of persuasive impressions as the method people ordinarily use to form beliefs, and it we can think that the Empiricist tradition contributed to this part of Pyrrhonian Skepticism.

Sextus Empiricus is our primary source for Pyrrhonian Skepticism. His Outlines of Pyrrhonism is in three books.



Outlines of Pyrrhonism I.1

The natural result of any investigation is that the investigators either discover the object of search or deny that it is discoverable and confess it not to be graspable or persist in their search. So, too, with regard to the objects investigated by philosophy, this is probably why some have claimed to have discovered the truth, others have asserted that it cannot be grasped, while others again go on inquiring.

Those who believe they have discovered the truth are called Dogmatists, for example, the schools of Aristotle and Epicurus and the Stoics and some others. The schools Clitomachus and Carneades and other Academics have asserted that it cannot be grasped. And the Skeptics keep on searching. Hence it seems reasonable to hold that the main types of philosophy are three—the Dogmatic, the Academic, and the Skeptic. The former two it will be appropriate for others to describe. In the present work, our task is to describe in outline the Skeptic philosophy. By way of preface let us say that on none of the matters to be discussed do we affirm that things certainly are just as we say they are. Rather, we simply record each fact, like a chronicler, as it appears to us at the time.


What Sextus says about the "natural result of any investigation" is a little puzzling. When the evidence does not decide the issue, we do not always "perist in [our] search" if that means we continue to gather evidence in an effort to decide the issue one way or another. Sometimes we leave the matter open and move on in our life.

We might expect Sextus know that there was a dispute within the Academy, but he does not do that in this passage. He treats the Academics as a group. He says that as a result of their investigation into the possibility of knowledge, the Academics "asserted that" and formed the belief that the truth is not graspable.

It is worth noting too that Sextus does not say that the Clitomachean Academics have no beliefs.



Outlines of Pyrrhonism I.8, I.10, I.12

Skepticism is an ability to set out oppositions among things which appear and are thought of in any way at all, an ability by which, because of the equipollence in the opposed objects and accounts, we come first to suspension of judgement and afterwards to tranquility.

By equipollence, we mean equality with respect to convincing or unconvincing: none of the conflicting accounts takes precedence over any other as more convincing. Suspension of judgement is a standstill of the intellect, owing to which we neither reject nor posit anything. Tranquility is freedom from disturbance or calmness of soul.

Skepticism we say originates in the hope of becoming tranquil. Men of talent, who were perturbed by the contradictions in things and in doubt as to which of the alternatives they ought to accept, were led on to inquire what is true in things and what false, thinking that by deciding this they would become tranquil. The main basic principle of Skepticism is the claim that to every account, an equal account is opposed; for it is from this, we think that we cease to dogmatize.


"equipollence" (σοσθένεια)

"accounts" (λόγοι)
We saw that Cicero said something similar about Arcesilaus.

"He thought that we shouldn’t assert or affirm anything, or approve it with assent: we should always curb our rashness and restrain ourselves from any slip. But he considered it particularly rash to approve something false or unknown, because nothing was more shameful than for one’s assent or approval to outrun knowledge and perception. His practice was consistent with this theory, so by arguing against everyone’s views he led most of them away from their own: when arguments of equal weight were found for the opposite sides of the same subject, it was easier to withhold assent from either side" (Academica I.45).

Cicero, though, does not talk about "tranquility or calmness of the soul."

We will think more about this later.



Outlines of Pyrrhonism I.13

When we say that the Skeptics do not hold beliefs, we do not take belief in the way in which some say, quite generally, that belief is acquiescing in something; for Skeptics assent to the feelings forced upon them by appearances--for example, they would not say, when heated or chilled, I think I not heated (or chilled). Rather, we say that they do not hold beliefs in the way in which some say that belief is an assent to some unclear object of investigation in the sciences; for Pyrrhonians do not assent to anything unclear.


Sextus draws a distinction somewhat like the one Cicero reports that Clitomachus draws.

We might expect him to mention Clitomachus here, but he does not.

What is the distinction Sextus draws?

We will think about this when we think about what Morison says about Frede's interpretation.



Outlines of Pyrrhonism I.19, I.20

Those who say that the Skeptics reject what is apparent have not listened to what we say. As we said before, we not overturn anything which leads us, without taking thought, to assent in accordance with an appearance we receive--and those things are precisely what is apparent. When we investigate whether existing things are such as they appear, we grant the one because it is apparent, and what we investigate is not what is apparent but what is said about what is apparent – and this is different from investigating what is apparent itself. "[Sextus has in mind] the canons and standards of rationality espoused by dogmatic philosophy, which the dogmatic philosopher insists on applying to any claim whatsoever, whether it be in mathematics or in ordinary life. It is only given these standards that it seems that one should withhold assent. But they are not the skeptic's standards, though he does not reject them, either. And thus Sextus often qualifies his remark that we have to withhold assent by saying that we have to withhold assent as far as this is a matter of reason or philosophical reason (ὅσον ἐπὶ τῷ φιλοσόφῳ λόγῳ; PH III, 65; I, 215; II, 26, 104; III, 6, 13, 29, 81, 135, 167)" (Frede 1987, 206).

"From the appearances, it seems that motion exists; as a matter of philosophical reason, it does not" (Outlines of Pyrrhonism III.65).

"From the appearances, motion exists; as a matter of philosophical reason, it does not" (Against the Physicists (M.X) II.49).

"The Skeptic does not live in accordance with philosophical reason--for he is inactive as far as this is concerned---but he is capable of choosing some things and avoiding others in accordance with non-philosophical observance" (Against the Ethicists (M.XI) 165).
For example, it appears to us that honey sweetens (we concede this inasmuch as we are sweetened in a perceptual way); but in so far it is sweet as a matter of reason (ὅσον ἐπὶ τῷ λόγῳ), that is something we investigate.

And if we do propound arguments directly against what is apparent, it is not because we want to reject what is apparent that we set them out, but rather to display the rashness of the Dogmatists; for if reason (λόγος) is such a deceive that it all but snatches even what is apparent from under our eyes, surely we should keep watch on it in unclear matters, to avoid being led into rashness by following it.


There is more information here about the kind of beliefs the Skeptic forms.

In I.13, Sextus says that the Skeptic forms beliefs by "acquiescing." Here, in I.19, he says that "we not overturn anything which leads us, without taking thought, to assent in accordance with an appearance we receive."

In I.13, Sextus says that the "Pyrrhonians do not assent to anything unclear." Here, in I.19, he seems to identify assenting to something unclear with forming a belief "as a matter of reason."



Outlines of Pyrrhonism I.23.

Thus, attending to what is apparent, we live in accordance with everyday observances, undogmatically, seeing that we are not able to be utterly inactive. These observances seem to be fourfold, and to consist in guidance by nature, necessitation by feelings, handing down of laws and customs, and teaching of kinds of expertise. By nature's guidance, we are naturally capable of sensation and thought. By the necessitation of feelings, hunger conducts us to food and thirst to drink, by the handing down of customs and laws, we accept, from an everyday point of view, that piety is good and impiety bad. By teaching of kinds of expertise, we are not inactive in those which we accept.


We are "naturally capable of sensation and thought" (φυσικῶς αἰσθητικοὶ καὶ νοητικοί).

What is this "thought"?

It would seem to be the everyday kind of reasoning in which we engage in living our lives.

In this case, there is everyday reasoning is not the reasoning involved in "assent to [something] unclear."

What is the difference?



Outlines of Pyrrhonism I.25, I.27, I.28

The Skeptic's end is tranquility in matters of opinion and moderation of feelings in things forced on us. For the Skeptic, having set out to philosophize to decide among the appearances and to apprehend which are true and which false, so as to become tranquil, came upon equipollent dispute, and being unable to decide between them suspended judgement. And when he suspended judgement, tranquility in matters of opinion followed fortuitously.

For those who hold the opinion that things are good or bad by nature are perpetually troubled. When they lack what they believe to be good, they take themselves to be persecuted by natural evils and they pursue what they think is good. And when they have acquired those things, they experience more troubles; for they are elated beyond reason and measure (τὸ παρὰ λόγον καὶ τὸ ἀμέτρως), and in fear of change they do anything so as not to lose what they believe to be good. But those who make no determination about what is good and bad by nature neither avoid nor pursue anything with intensity; and hence they are tranquil.

A story told of the painter Apelles applies to the Skeptics. They say that he was painting a horse and wanted to represent the lather on the horse's mouth; but he was so unsuccessful that he gave up, took the sponge on which he had been wiping off the colors from his brush, and flung it at the picture. And when it hit the painting, it produced a representation of the horse's lather. Now the Skeptics were hoping to acquire tranquility by deciding the anomalies in what appears and is thought of, and being unable to this they suspended judgement. But when they suspended judgement, tranquility followed fortuitously, as a shadow follows a body.


Sextus opposes the Skeptic with "those who hold the opinion that things are good or bad by nature."

His description of their "perpetual trouble" sounds a lot like what the Stoics say of the fool. The fool suffers from excessive impulses because he has false beliefs about what is good and what is bad.

The Stoic sage does not suffer like the fool because he knows that wisdom is the only good.

What is the corresponding answer for the Skeptic?

It does not seem that the answer can be that the Skeptic has no beliefs about what is good and bad. In I.23, Sextus says that the Skeptics "accept, from an everyday point of view, that piety is good and impiety bad."



"There have been, as the most say, three Academies—the most ancient one, that of Plato and his followers ; the second and middle one, that of Arcesilaus and his followers, Arcesilaus being the pupil of Polemo ; the third and new Academy, that of Carneades and Clitomachus and their followers ; some add also a fourth, that of Philo and Charmides, and their followers ; and some count even a fifth, that of Antiochus and his followers" (Outlines of Pyrrhonism I.220).

"For the Academics say that things are good and bad not in the way we do, but the conviction that it is persuasive what they call good rather than its contrary really is good (and similarly with bad), whereas we do not call anything good or bad with the thought that what we say is persuasive--rather, without holding opinions we follow ordinary life in order to be inactive" (Outlines of Pyrrhonism I.226).

"Those who profess to belong to the Academy use the persuasive in their lives, while we follow laws and customs and natural feelings, and so live without holding opinions" (Outlines of Pyrrhonism I.231).
Outlines of Pyrrhonism I.226, I.227, I.229

The adherents of the New Academy, although they affirm that nothing is graspable, yet differ from the Skeptics in respect of this very statement that nothing is graspable. For they affirm this positively.

And as regards impressions, we say they are equal in respect of persuasiveness, so far as this is a matter of reason, whereas they [in the New Academy] assert that some impressions are persuasive, others not.

The Academics and Skeptics both say they believe certain things, but the difference even here between the two is clear. For believe is said in different ways. Sometimes it means not resisting but simply following without strong inclination or adherence (as a boy is said to believe his teacher; and sometimes it signifies assenting to something by choice and, as it were, sympathy (as a dissolute man goes along with someone who urges extravagant living). Since Carneades and Clitomachus say they believe with a strong inclination that some things are persuasive, whereas we say our belief is simply yielding without adherence, in this respect too we differ from them.


Sextus describes a right way to form beliefs and a wrong way.

What is the wrong way?

Consider the example of the "dissolute man." We should go to the party, someone says to him. The dissolute man agrees. He forms the belief that they should go because it gives him pleasure to think this proposition is true.

"Carneades and Clitomachus say they believe with a strong inclination that some things are persuasive."

I know of no text where they say this.

The closest is Academica II.148. Catulus is the speaker.

"I am returning to my father’s view, which he at least said was Carneades’s. That is, while I don’t think that anything can be perceived, I still reckon that the wise man will assent to something he hasn’t perceived—that is, hold opinions—but in such a way that he understands that it is an opinion and realizes that nothing is can be comprehended and perceived. And therefore although I ‡ ... ‡ with their rule of ἐποχή [suspension], I assent emphatically (vehementer) to that second view that nothing can be perceived."

How does Catulus look from the point of view of the Skeptic?

In so far as it is a matter of reason, Catulus should suspend assent. This, though, is not what he does. He chooses to believe that nothing is perceivable because it gratifies him to think that this is how the world is.


Frede on the Pyrrhonian Skeptics

Frede set out his interpretation of Pyrrhonian Skepticism in two now classic papers in the history of philosophy.

The papers are "The Skeptic's Beliefs" (1979) and "The Skeptic's Two Kinds of Assent and the Question of the Possibility of Knowledge" (1984). Frede reprinted them in his Essays in Ancient Philosophy (1987).

These papers generated considerable interest in the history of philosophy and some interest in philosophy more generally. Hackett reprinted Frede's papers in The Original Sceptics. A Controversy (1998).

Frede's view, though, is not straightforward to see. So we will consider the interpretation Benjamin Morison gives in his Stanford Encyclopedia of Philosophy entry on Sextus Empiricus (2014 and 2019).

The part of Morison's entry that primarily interests us is his section (3.4) on whether the Skeptic has beliefs.

Frede argues that the Pyrrhonian Skeptic has Beliefs

"[T]he problem is solved for us by Sextus Empiricus' own words. In P.H I 13ff., Sextus explains in what sense the skeptic is not dogmatic. What is not in question, at least if we follow Sextus, is whether the skeptic has no dogmas, no beliefs at all but whether he has no beliefs of a certain sort. Sextus distinguishes between a wider (koinoteron) and a narrower sense of 'belief; and only beliefs in the narrower sense count as dogmatic. Hence, there can be no doubt whatsoever that, according to Sextus, a serious Pyrrhonean skeptic can have beliefs" (Frede 1987, 186). Frede argues that the Pyrrhonian Skeptics (and perhaps the Academics too) took themselves to have beliefs and thought that having beliefs is perfectly compatible with suspending judgment on all matters.

"The objectors claim that the skeptics, in theory, suspend judgment on all matters, but that, in practice, they simply cannot avoid making all kinds of judgments. Thus, one could argue against the objection by (i) trying to show that the skeptics denied that one could not avoid making judgments in practice, in everyday life-.... The skeptics could grant that it is extraordinarily difficult to bring oneself into such a state that one no longer even feels any temptation to have any view but insist that it is, in principle, possible and, indeed, is compatible with living a life worth living. Or, (ii) one could argue that the skeptics thought that even if one suspended judgment on all matters, at least suspended judgment in the sense in which they recommend that one suspend judgment, one would still have many beliefs and views, quite enough, at any rate, to lead a worthwhile life. For various reasons—which I shall come to—it seems as if the skeptics opted for the second line" (Frede 1987, 180-181).

"What needs to be asked is what sorts of beliefs these are, and how is the fact that the skeptic does have beliefs compatible with the claim that the skeptic suspends judgment about every issue" (Frede 1987, 186). To sustain this interpretation of Pyrrhonian Skepticism, Frede needs to explain how the Skeptic can reasonably think that having beliefs is compatible with also suspending judgment on all matters.

The first step is to identify the beliefs the Skeptic takes himself to possess.

Morison takes Frede to think that the Pyrrhonian Skeptic thinks there are two ways to acquire a belief. There is the "everyday" way, and there is the "marshalling arguments and evidence" way.

"The trick is to see that the Skeptics can hold beliefs, but just in an ordinary everyday way (‘from an everyday point of view,’ as [Sextus Empiricus] says in the passage above [Outlines of Pyrrhonism I.24]), i.e., not as a result of marshalling arguments and evidence in favour of those beliefs, as philosophers and scientists do" (Benjamin Morison, "Sextus Empiricus," The Stanford Encyclopedia of Philosophy, 2014, 2019).

“Frede's view [of the kind of belief the skeptic cannot have and the kind that the skeptic can have] is best captured by the distinction … between coming to believe something on the basis of marshalling reasons for and against it, and coming to believe it because you are going along with an impression you have” (Benjamin Morison, "Supplement to Sextus Empiricus," The Stanford Encyclopedia of Philosophy, 2014, 2019).

"[W]hat the skeptic literally accepts, what he is content with, what he has no objection to is whatever seems to him to be the case, whatever seems evident to him. He accepts the judgment of phantasia; at least he raises no objection against its verdict; if it says things are thus or thus, he does not challenge this" (Frede 1987, 194). The everyday way is "going along with the impression you have."

This way of acquiring a belief is a little puzzling because it is supposed be both the "everyday" way and not involve "marshalling arguments and evidence." The "everyday" way of acquiring beliefs, though, is what people ordinarily do, and it seems that ordinarily people who are not "philosophers and scientists" do sometimes form their beliefs by "marshalling arguments and evidence" for the proposition they come to believe.

Here is an example. I have a tracking device on something I value. I wonder where this thing is now. To find out, I look at the tracking app. It shows me that it is in my office at school. Now I believe I know where it is.

Maybe, though, as the Skeptic would understand this, I am not "marshalling arguments and evidence."

Is this at all plausible?

Morison does not consider this issue.

Frede himself makes some remarks that help provide a solution.

"[E]verything, if considered only as an object for reason, can be called into question; every question can be regarded as a question to be answered by reason, a question requiring a theoretical answer derived from first principles which are immediately evident to reason. Nothing, looked at in this way, will be evident to the skeptic, not even the most lowly, ordinary belief. Any belief, whatever its content may be, can be a dogmatic belief; conversely, every belief can be an undogmatic one. Thus, it is not the content of theoretical views (though, as we shall see, content is not entirely irrelevant) that makes them dogmatic views; it is, rather, the attitude of the dogmatist who believes his rationalist science actually answers questions, actually gives him good reasons for believing his theoretical doctrines" (Frede 1987, 195).

"[Outlines of Pyrrhonism I.24] says only that the skeptic may not have beliefs of a certain kind, viz., philosophical or scientific ones which depend on reasoned grounds (here, of course, he is presupposing a dogmatic notion of knowledge and science; if there can be such a thing as skeptical science remains to be seen)" (Frede 1987, 195).

This suggests that the Skeptic, as Frede understands him, accepts the everyday reasoning and "marshalling arguments and evidence" in play the example I gave. What he rejects is reason as the Dogmatics understand it.

Frede's "An empiricist view of knowledge: memorism" (1990) provides more evidence:

"[W]e know from Sextus Empiricus that Pyrrhoneans did not want to deny reason as such, given that it seemed obvious that human beings do reason (PH I.24)" ("An empiricist view of knowledge: memorism," 249).

A Way to Understand Frede's Interpretation

This gives us a way to understand Frede's interpretation of Pyrrhonian Skepticism.

The Skeptic forms beliefs by reasoning in the everyday way. An instance of this reasoning is marshalling arguments and evidence. The Skeptic forms these beliefs about himself by reasoning in the everyday way.

The Skeptic also believes that if we use the reason of the Dogmatists to form our beliefs, we must suspend judgment because this reason always leaves us with arguments of equal weight for and against.

The Connection to the Academy

Frede's interpretation, as I am understanding it, is close to the interpretation I constructed of the dispute between the Academics and the Stoics. The Academics believe that no impression is cognitive, and they try to show the Stoics that they themselves are committed to thinking that they should never assent.

What we do not see in Sextus Empiricus is any awareness of the dispute in the Academy about how to understand Academic practice. He does not align the Skeptic with the Clitomacheans and against the Philonan Academics. He treats the Academics as Dogmatists who hold beliefs they take "philosophical reason" to justify.

This understanding of the Academy may go back to Aenesidemus.

"In the argument of the first book, Aenesidemus introduces the difference between the Pyrrhonists and the Academics in almost these words. The Academics are dogmatists..." (Photius, Bibliotheca 212.169b).







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