Moscow State Institute of International Relations MGIMOUniversity School

Moscow State Institute of International Relations (MGIMO-University) School of Government and International Affairs & Alexander Shishkin Department of Philosophy The Basics of Philosophy Part III Anthropocentric Philosophy Lecture 9 Ancient Scepticism The Uncertainty of Knowledge

Ancient Scepticism The Uncertainty of Knowledge q Pyrrhonism • Pyrrhon: The Suspension of Judgement q Academic Scepticism • Arcesilaus: Acatalepsy and Verisimilitude q Later Pyrrhonism • Aenesidemus: The Unreliability of Sense Perception § The Trope of Differences in Animals § The Trope of Differences in Human Beings § The Trope of Differences in the Senses § The Trope of Differences in Circumstances • Agrippa: The Unreliability of Reasoning § The Trope of Infinite Regress § The Trope of Hypothesis § The Trope of Circular Reasoning • Sextus Empiricus: Systematisation of Scepticism

Ancient Scepticism The Uncertainty of Knowledge Academic Scepticism Pyrrhon of Elis Timon c. 360 – c. 272 B. C. of Phlius The Middle Academy 325/20 – 235/30 The Elder Sceptics Arcesilaus of Pitane The Younger Sceptics 315 – c. 241 1 st c. B. C. Agrippa 1 st / 2 nd c. A. D. Carneades of Cyrene 214/13 – 129/28 Aenesidemus of Knossos The New Academy Sextus Empiricus 2 nd / 3 rd c. A. D. Cleitomachus of Carthage 187/86 – 110/09

Ancient Scepticism The Uncertainty of Knowledge Sinope Rome Abdera Stagira Elea Pitane Athens Elis Carthage Cyrene Ephesus Phlius Miletus Knossos Alexandria Soli Citium

Ancient Scepticism The Uncertainty of Knowledge Principal Writings • Sextus Empiricus. Outlines of Pyrrhonism • Sextus Empiricus. Against the Mathematicians § Against the Professors § § § Against the Grammarians Against the Rhetoricians Against the Geometricians Against the Arithmeticians Against the Astrologers Against the Musicians § Against the Dogmatists § Against the Logicians § Against the Physicists § Against the Ethicists Sextus Empiricus 2 nd or 3 rd c. A. D.

Pyrrhonism What are things like by nature? The nature of things is indeterminate (unknown). How should we be disposed towards things? What will be the outcome for those who adopt this disposition? We should be unopinionated (indifferent). We shall enjoy the state of ataraxia (freedom from anxiety).

Pyrrhon The Suspension of Judgement Isostheneia Epoché (Gr. ίσοσθένεια) means “equal strength” (of contradicting propositions). (Gr. εποχή) means “suspension of judgement”. One cannot say about each single thing that it no more is than is not or both is and is not or neither is not. For want of a reliable criterion of truth, one cannot tell a true proposition from a false one.

Pyrrhon The Suspension of Judgement Ataraxia (Gr. αταραξία, from α, privative, and ταραχή, anxiety) is a state of tranquillity, characterized by freedom from distress and worry. Sceptic (Gr. σκεπτικός, thoughtful , from Gr. ςκέπτεσθαι, to consider) means “the one who considers”.

Academic Scepticism Acatalepsy and Verisimilitude Acatalepsy (Gr. , incomprehensibleness, from α, privative, and καταλαμβάνειν, to seize) is incomprehensibleness; the term also indicates a state of mind in which all judgement is suspended due to inability to attain certain knowledge.

Academic Scepticism Acatalepsy and Verisimilitude Opinions differ from knowledge, and there is nothing intermediate between these two. Even fools are capable of holding and expressing opinions, but wise men seek knowledge. Arcesilaus and Carneades Understanding, however, that certain knowledge is unattainable, wise men eschew opinions and practise acatalepsy. Though judgements are to be suspended in theory, one cannot avoid making practical decisions. For want of reliable knowledge, in practical matters one is to be guided by verisimilitude (εὔλογον).

Later Pyrrhonism The usual tradition amongst the older sceptics is that the “modes” by which “suspension” is supposed to be brought about are ten in number; and they also give them the synonymous names of “arguments” (λόγοι) and “positions (τόποι). ” Sextus Empiricus. Outlines of Pyrrhonism.

Aenesidemus The Unreliability of Sense Perception Sextus Empiricus. Outlines of Pyrrhonism. They are these: the first, based on the variety in animals; the second, on the differences in human beings; the third, on the different structures of the organs of sense; the fourth, on the circumstantial conditions; the fifth, on positions and intervals and locations; the sixth, on intermixtures; the seventh, on the quantities and formations of the underlying objects; the eighth, on the fact of relativity; the ninth, on the frequency or rarity of occurrence; the tenth, on the disciplines and customs and laws, the legendary beliefs and the dogmatic convictions.

Aenesidemus’ First Trope The Differences in Animals The First argument (or Trope), as we said, is that which shows that the same impressions(φαντασία) are not produced by the same objects owing to the differences in animals. This we infer both from the differences in their origins and from the variety of their bodily structures. Sextus Empiricus. Outlines of Pyrrhonism.

Aenesidemus’ First Trope The Differences in Animals 1. Different animals sense things in different ways, and it is impossible to establish whose perception is “correct”.

Aenesidemus’ Second Trope The Differences in Human Beings The Second Mode is, as we said, that based on the differences in men; for even if we grant for the sake of argument that men are more worthy of credence than irrational animals, we shall find that even our own differences of themselves lead to suspense. For man, you know, is said to be compounded of two things, soul and body, and in both these we differ one from another. Sextus Empiricus. Outlines of Pyrrhonism.

Aenesidemus’ Second Trope The Differences in Human Beings 1. Different animals sense things in different ways, and it is impossible to establish whose perception is “correct”. 2. Even if we choose (without good reason) to rely on human perception, we must admit that different people sense in different ways, too.

Aenesidemus’ Third Trope The Differences in the Senses When the Dogmatists – a self-loving class of men – assert that in judging things they ought to prefer themselves to other people, we know that their claim is absurd; for they themselves are a party to the controversy; and if, when judging appearances, they have already given the preference to themselves, then, by thus entrusting themselves with the judgment, they are begging the question before the judgment is begun. Sextus Empiricus. Outlines of Pyrrhonism.

Aenesidemus’ Third Trope The Differences in the Senses Nevertheless, in order that we may arrive at suspension of judgment by basing our argument on one person – such as, for example, their visionary “Sage” – we adopt the Mode which comes Third in order. This Third Mode is, we say, based on differences in the senses. That the senses differ from one another is obvious. Sextus Empiricus. Outlines of Pyrrhonism.

Aenesidemus’ Third Trope The Differences in the Senses 1. Different animals sense things in different ways, and it is impossible to establish whose perception is “correct”. 2. Even if we choose (without good reason) to rely on human perception, we must admit that different people sense in different ways, too. 3. Even if we choose (for whatever reason) to rely on a particular person, that one person has different organs of sense that provide different evidence.

Aenesidemus’ Fourth Trope The Differences in Circumstances In order that we may finally reach suspension by basing our argument on each sense singly, or even by disregarding the senses, we further adopt the Fourth Mode of suspension. This is the Mode based, as we say, on the “circumstances, ” meaning by “circumstances” conditions or dispositions. Sextus Empiricus. Outlines of Pyrrhonism.

Aenesidemus’ Fourth Trope The Differences in Circumstances 1. Different animals sense things in different ways, and it is impossible to establish whose perception is “correct”. 2. Even if we choose (without good reason) to rely on human perception, we must admit that different people sense in different ways, too. 3. Even if we choose (for whatever reason) to rely on a particular person, that one person has different organs of sense that provide different evidence. 4. Even if we have good reason to rely on one of the senses rather than another, its evidence differs depending on circumstantial conditions.

Aenesidemus’ Fifth Trope The Differences in Positions and Distances The Fifth Argument (or Trope) is that based on positions, distances, and locations; for owing to each of these the same objects appear different… Sextus Empiricus. Outlines of Pyrrhonism.

Aenesidemus’ Fifth Trope The Differences in Positions and Distances 1. Different animals sense things in different ways, and it is impossible to establish whose perception is “correct”. 2. Even if we choose (without good reason) to rely on human perception, we must admit that different people sense in different ways, too. 3. Even if we choose (for whatever reason) to rely on a particular person, that one person has different organs of sense that provide different evidence. 4. Even if we have good reason to rely on one of the senses rather than another, its evidence differs depending on circumstantial conditions. 5. Objects appear different depending on their position, distance, and location.

Aenesidemus’ Sixth Trope Admixtures and Conjunctions The Sixth Mode is that based on admixtures, by which we conclude that, because none of the real objects affects our senses by itself but always in conjunction with something else, though we may possibly be able to state the nature of the resultant mixture formed by the external object and that along with which it is perceived, we shall not be able to say what is the exact nature of the external reality in itself. Sextus Empiricus. Outlines of Pyrrhonism.

Aenesidemus’ Sixth Trope Admixtures and Conjunctions That none of the external objects affects our senses by itself but always in conjunction with something else, and that, in consequence, it assumes a different appearance, is, I imagine, quite obvious. Sextus Empiricus. Outlines of Pyrrhonism.

Aenesidemus’ Sixth Trope Admixtures and Conjunctions 1. Different animals sense things in different ways, and it is impossible to establish whose perception is “correct”. 2. Even if we choose (without good reason) to rely on human perception, we must admit that different people sense in different ways, too. 3. Even if we choose (for whatever reason) to rely on a particular person, that one person has different organs of sense that provide different evidence. 4. Even if we have good reason to rely on one of the senses rather than another, its evidence differs depending on circumstantial conditions. 5. Objects appear different depending on their position, distance, and location. 6. No object affects our senses by itself but always in conjunction with something else.

Aenesidemus’ Seventh Trope The Differences in Quantities and Constitutions The Seventh Mode is that based, as we said, on the quantity and constitution of the underlying objects, meaning generally by “constitution” the manner of composition. And it is evident that by this Mode also we are compelled to suspend judgment concerning the real nature of the objects. Sextus Empiricus. Outlines of Pyrrhonism.

Aenesidemus’ Seventh Trope The Differences in Quantities and Constitutions 1. Different animals sense things in different ways, and it is impossible to establish whose perception is “correct”. 2. Even if we choose (without good reason) to rely on human perception, we must admit that different people sense in different ways, too. 3. Even if we choose (for whatever reason) to rely on a particular person, that one person has different organs of sense that provide different evidence. 4. Even if we have good reason to rely on one of the senses rather than another, its evidence differs depending on circumstantial conditions. 5. Objects appear different depending on their position, distance, and location. 6. No object affects our senses by itself but always in conjunction with something else. 7. Objects appear different depending on their quantities and constitutions.

Aenesidemus’ Eighth Trope The Trope of Relativity The Eighth Mode is that based on relativity; and by it we conclude that, since all things are relative, we shall suspend judgment as to what things are absolutely and really existent. Sextus Empiricus. Outlines of Pyrrhonism.

Aenesidemus’ Eighth Trope The Trope of Relativity 1. Different animals sense things in different ways, and it is impossible to establish whose perception is “correct”. 2. Even if we choose (without good reason) to rely on human perception, we must admit that different people sense in different ways, too. 3. Even if we choose (for whatever reason) to rely on a particular person, that one person has different organs of sense that provide different evidence. 4. Even if we have good reason to rely on one of the senses rather than another, its evidence differs depending on circumstantial conditions. 5. Objects appear different depending on their position, distance, and location. 6. No object affects our senses by itself but always in conjunction with something else. 7. Objects appear different depending on their quantities and constitutions. 8. All things appear relative, i. e. in relation both to other things and to the perceiver.

Aenesidemus’ Ninth Trope Constancy or Rarity of Occurrence The Mode which, as we said, comes Ninth in order is based on constancy or rarity of occurrence, and we shall explain it as follows. The sun is, of course, much more amazing than a comet; yet because we see the sun constantly but the comet rarely, we are so amazed by the comet that we even regard it as a divine portent, while the sun causes no amazement at all. Sextus Empiricus. Outlines of Pyrrhonism.

Aenesidemus’ Ninth Trope Constancy or Rarity of Occurrence 1. Different animals sense things in different ways, and it is impossible to establish whose perception is “correct”. 2. Even if we choose (without good reason) to rely on human perception, we must admit that different people sense in different ways, too. 3. Even if we choose (for whatever reason) to rely on a particular person, that one person has different organs of sense that provide different evidence. 4. Even if we have good reason to rely on one of the senses rather than another, its evidence differs depending on circumstantial conditions. 5. Objects appear different depending on their position, distance, and location. 6. No object affects our senses by itself but always in conjunction with something else. 7. Objects appear different depending on their quantities and constitutions. 8. All things appear relative, i. e. in relation both to other things and to the perceiver. 9. Perception of objects depends on the constancy or rarity of occurrence.

Aenesidemus’ Tenth Trope The Differences in Habits and Beliefs There is a Tenth Mode, which is mainly concerned with Ethics, being based on rules of conduct, habits, laws, legendary beliefs, and dogmatic conceptions. Sextus Empiricus. Outlines of Pyrrhonism.

Aenesidemus’ Tenth Trope The Differences in Habits and Beliefs 1. Different animals sense things in different ways, and it is impossible to establish whose perception is “correct”. 2. Even if we choose (without good reason) to rely on human perception, we must admit that different people sense in different ways, too. 3. Even if we choose (for whatever reason) to rely on a particular person, that one person has different organs of sense that provide different evidence. 4. Even if we have good reason to rely on one of the senses rather than another, its evidence differs depending on circumstantial conditions. 5. Objects appear different depending on their position, distance, and location. 6. No object affects our senses by itself but always in conjunction with something else. 7. Objects appear different depending on their quantities and constitutions. 8. All things appear relative, i. e. in relation both to other things and to the perceiver. 9. Perception of objects depends on the constancy or rarity of occurrence. 10. Perceptions depend on habits and beliefs that vary among cultures.

Aenesidemus’ Tenth Trope The Differences in Habits and Beliefs

Aenesidemus The Unreliability of Sense Perception Sextus Empiricus. Outlines of Pyrrhonism. As superordinate to these there stand three Modes – that based on the subject who judges, that on the object judged, and that based on both. The first four of the ten Modes are subordinate to the Mode based on the subject (for the subject which judges is either an animal or a man or a sense, and existent in some condition); the seventh and tenth Modes are referred to that based on the object judged; the fifth, sixth, eighth, and ninth are referred to the Mode based on both subject and object.

Aenesidemus The Unreliability of Sense Perception Furthermore, these three Modes are also referred to that of relation, so that the Mode of relation stands as the highest genus, and the three as species, and the ten as subordinate subspecies. Sextus Empiricus. Outlines of Pyrrhonism.

Aenesidemus The Unreliability of Sense Perception is a process that provides a subject information about an object. It seems expedient from this standpoint to change the order of Aenesidemus’ tropes by shifting his 10 th trope onto the 5 th place and his 8 th trope onto the 10 th place. The first five tropes (Aenesidemus’ 1 st, 2 nd, 3 rd, 4 th, and 10 th) argue for the unreliability of sense perception from the plurality and peculiarities of subjects.

Aenesidemus The Unreliability of Sense Perception q Different animals sense things in different ways, and it is impossible to establish whose perception is “correct”. q Even if we choose (without good reason) to rely on human perception, we must admit that different people sense in different ways, too. q Even if we choose (for whatever reason) to rely on a particular person, that one person has different organs of sense that provide different evidence. q Even if we have good reason to rely on one of the senses rather than another, its evidence differs depending on circumstantial conditions. q Perceptions depend on habits and beliefs that vary among cultures.

Aenesidemus The Unreliability of Sense Perception Sense perception is a process that provides a subject information about an object. It seems expedient from this standpoint to change the order of Aenesidemus’ tropes by shifting his 10 th trope onto the 5 th place and his 8 th trope onto the 10 th place. The first five tropes (Aenesidemus’ 1 st, 2 nd, 3 rd, 4 th, and 10 th) argue for the unreliability of sense perception from the plurality and peculiarities of subjects. The following four tropes (Aenesidemus’ 5 th, 6 th, 7 th, and 9 th) argue for the unreliability of sense perception from the plurality and peculiarities of objects.

Aenesidemus The Unreliability of Sense Perception q Different animals sense things in different ways, and it is impossible to establish whose perception is “correct”. q Even if we choose (without good reason) to rely on human perception, we must admit that different people sense in different ways, too. q Even if we choose (for whatever reason) to rely on a particular person, that one person has different organs of sense that provide different evidence. q Even if we have good reason to rely on one of the senses rather than another, its evidence differs depending on circumstantial conditions. q Perceptions depend on habits and beliefs that vary among cultures. ₪ No object affects our senses by itself but always in conjunction with something else. ₪ Objects appear different depending on their position, distance, and location. ₪ Objects appear different depending on their quantities and formations. ₪ Perception of objects depends on the constancy or rarity of occurrence. The last trope sums up.

Aenesidemus The Unreliability of Sense Perception q Different animals sense things in different ways, and it is impossible to establish whose perception is “correct”. q Even if we choose (without good reason) to rely on human perception, we must admit that different people sense in different ways, too. q Even if we choose (for whatever reason) to rely on a particular person, that one person has different organs of sense that provide different evidence. q Even if we have good reason to rely on one of the senses rather than another, its evidence differs depending on circumstantial conditions. q Perceptions depend on habits and beliefs that vary among cultures. ₪ No object affects our senses by itself but always in conjunction with something else. ₪ Objects appear different depending on their position, distance, and location. ₪ Objects appear different depending on their quantities and formations. ₪ Perception of objects depends on the constancy or rarity of occurrence. ۞ All things appear relative, i. e. in relation both to other things and to the perceiver.

Agrippa The Unreliability of Reasoning • • • The Elder Sceptics (of whom Aenesidemus is the only one we may name) reason that sense perception is unreliable. Since sceptics themselves do not hesitate to resort to reason and do it not without success, the obvious question to ask is whether reasoning may correct the defects of sense perception. Alas, no. Our mental capacities suffice to realise how doubtful and untrustworthy our sense perception is. However, as the Younger Sceptics (of whom Agrippa is the only one known to us, and even he merely by name) demonstrate, they prove not effective enough to help us retrieve reliable and certain knowledge from the unreliable and uncertain information provided by the senses.

Agrippa The Unreliability of Reasoning The later Sceptics hand down Five Modes leading to suspension, namely these: the first based on discrepancy, the second on regress ad infinitum, the third on relativity, the fourth on hypothesis, the fifth on circular reasoning. Sextus Empiricus. Outlines of Pyrrhonism.

Agrippa’ First Trope The Trope of Discrepancy [The trope] based on discrepancy leads us to find that with regard to the object presented there has arisen both amongst ordinary people and amongst the philosophers an interminable conflict because of which we are unable either to choose a thing or reject it, and so fall back on suspension. Sextus Empiricus. Outlines of Pyrrhonism.

Agrippa’ First Trope The Trope of Discrepancy • The trope of discrepancy: people’s opinions, both assumptions and judgements, contradict each other.

Agrippa’ Second Trope The Trope of Infinite Regress The Mode based upon regress ad infinitum is that whereby we assert that the thing adduced as a proof of the matter proposed needs a further proof, and this again another, and so on ad infinitum, so that the consequence is suspension, as we possess no starting point for our argument. Sextus Empiricus. Outlines of Pyrrhonism.

Agrippa’ Second Trope The Trope of Infinite Regress • The trope of discrepancy: people’s opinions, both assumptions and judgements, contradict each other. q The trope of infinite regress: the thing adduced as a proof is itself in need of a proof, and so on ad infinitum. A > F F > D D > G A > D G > C D > C C > I I > E E > J C > E A > C E > B C > B A > B J > B

Agrippa’ Third Trope The Trope of Relativity The Mode based upon relativity, as we have already said, is that whereby the object has such or such an appearance in relation to the subject judging and to the concomitant percepts, but as to its real nature we suspend judgment. Sextus Empiricus. Outlines of Pyrrhonism.

Agrippa’ Third Trope The Trope of Relativity • The trope of discrepancy: people’s opinions, both assumptions and judgements, contradict each other. q The trope of infinite regress: the thing adduced as a proof is itself in need of a proof, and so on ad infinitum. • The trope of relativity: all judgements are relative, i. e. not about the intrinsic nature of a thing, but about its relation to other things and to the one who judges.

Agrippa’ Fourth Trope The Trope of Hypothesis We have the Mode based on hypothesis when the Dogmatists, being forced to recede ad infinitum, take as their starting-point something which they do not establish by argument but claim to assume as granted simply and without demonstration. Sextus Empiricus. Outlines of Pyrrhonism.

Agrippa’ Fourth Trope The Trope of Hypothesis • The trope of discrepancy: people’s opinions, both assumptions and judgements, contradict each other. q The trope of infinite regress: the thing adduced as a proof is itself in need of a proof, and so on ad infinitum. • The trope of relativity: all judgements are relative, i. e. not about the intrinsic nature of a thing, but about its relation to other things and to the one who judges. q The trope of hypothesis: to avoid infinite regress, dogmatists proceed from assumptions arbitrarily taken to be true.

Agrippa’ Fifth Trope The Trope of Circular Reasoning The Mode of circular reasoning is the form used when the proof itself which ought to establish the matter of inquiry requires confirmation derived from that matter; in this case, being unable to assume either in order to establish the other, we suspend judgment about both. Sextus Empiricus. Outlines of Pyrrhonism.

Agrippa’ Fifth Trope The Trope of Circular Reasoning • The trope of discrepancy: people’s opinions, both assumptions and judgements, contradict each other. q The trope of infinite regress: the thing adduced as a proof is itself in need of a proof, and so on ad infinitum. • The trope of relativity: all judgements are relative, i. e. not about the intrinsic nature of a thing, but about its relation to other things and to the one who judges. q The trope of hypothesis: to avoid infinite regress, dogmatists proceed from assumptions arbitrarily taken to be true. q The trope of circular reasoning: every proof offered to establish the matter of inquiry requires confirmation derived from the very matter it is supposed to prove. All humans are mortal Socrates is human Socrates is mortal

Agrippa’ Fifth Trope The Trope of Circular Reasoning • The trope of discrepancy: people’s opinions, both assumptions and judgements, contradict each other. q The trope of infinite regress: the thing adduced as a proof is itself in need of a proof, and so on ad infinitum. • The trope of relativity: all judgements are relative, i. e. not about the intrinsic nature of a thing, but about its relation to other things and to the one who judges. q The trope of hypothesis: to avoid infinite regress, dogmatists proceed from assumptions arbitrarily taken to be true. q The trope of circular reasoning: every proof offered to establish the matter of inquiry requires confirmation derived from the very matter it is supposed to prove. Aristotle is mortal Plato is mortal Diogenes is mortal Some humans are mortal All humans are mortal … Socrates is human Is Socrates mortal? Socrates is mortal

Agrippa’ Fifth Trope The Trope of Circular Reasoning • The trope of discrepancy: people’s opinions, both assumptions and judgements, contradict each other. q The trope of infinite regress: the thing adduced as a proof is itself in need of a proof, and so on ad infinitum. • The trope of relativity: all judgements are relative, i. e. not about the intrinsic nature of a thing, but about its relation to other things and to the one who judges. q The trope of hypothesis: to avoid infinite regress, dogmatists proceed from assumptions arbitrarily taken to be true. q The trope of circular reasoning: every proof offered to establish the matter of inquiry requires confirmation derived from the very matter it is supposed to prove. Aristotle is mortal Plato is mortal Diogenes is mortal Some humans are mortal All humans are mortal … Socrates is mortal Socrates is human Is Socrates mortal? Socrates is mortal

Agrippa’ Fifth Trope The Trope of Circular Reasoning • The trope of discrepancy: people’s opinions, both assumptions and judgements, contradict each other. q The trope of infinite regress: the thing adduced as a proof is itself in need of a proof, and so on ad infinitum. • The trope of relativity: all judgements are relative, i. e. not about the intrinsic nature of a thing, but about its relation to other things and to the one who judges. q The trope of hypothesis: to avoid infinite regress, dogmatists proceed from assumptions arbitrarily taken to be true. q The trope of circular reasoning: every proof offered to establish the matter of inquiry requires confirmation derived from the very matter it is supposed to prove. All birds are mortal All fish are mortal All cats are mortal All animals are mortal … All humans are mortal All humans are animals All humans are mortal

Sextus Empiricus Systematisation of Scepticism We have two instruments of cognition, viz. sense perception and reason. As the tropes of the elder sceptics demonstrate, sense perception cannot serve as a reliable criterion of truth. As the tropes of the younger sceptics demonstrate, reasoning cannot serve as a reliable criterion of truth, either. Consequently, we have no reliable criterion of truth at all.

Questions?