Ancient Greek Skepticism [Internet Encyclopedia of Philosophy]
Ancient Greek Skepticism
Although all skeptics in some way cast doubt on our ability to gain
knowledge of the world, the term 'skeptic' actually covers a wide
range of attitudes and positions. There are skeptical elements in
the views of many Greek philosophers, but the term 'ancient skeptic'
is generally applied either to a member of Plato's Academy during its
skeptical period (c. 273 B.C.E to 1st century B.C.E.) or to a
follower of Pyrrho (c. 365 to 270 B.C.E.). Pyrrhonian skepticism
flourished from Aenesidemus' revival (1st century B.C.E.) to Sextus
Empiricus, who lived sometime in the 2nd or 3rd centuries C.E. Thus
the two main varieties of ancient skepticism: Academic and
Pyrrhonian.
The term 'skeptic' derives from a Greek noun, skepsis, which
means examination, inquiry, consideration. What leads most skeptics
to begin to examine and then eventually to be at a loss as to what
one should believe, if anything, is the fact of widespread and
seemingly endless disagreement regarding issues of fundamental
importance. Many of the arguments of the ancient skeptics were
developed in response to the positive views of their contemporaries,
especially the Stoics and Epicureans, but
these arguments have been highly influential for subsequent
philosophers and will continue to be of great interest as long as
there is widespread disagreement regarding important philosophical
issues.
Nearly every variety of ancient skepticism includes a thesis
about our epistemic limitations and a thesis about suspending
judgment. The two most frequently made objections to skepticism
target these theses. The first is that the skeptic's commitment to
our epistemic limitations is inconsistent. He cannot consistently
claim to know, for example, that knowledge is not possible; neither
can he consistently claim that we should suspend judgment regarding
all matters insofar as this claim is itself a judgment. Either such
claims will refute themselves, since they fall under their own scope,
or the skeptic will have to make an apparently arbitrary exemption.
The second sort of objection is that the alleged epistemic
limitations and/or the suggestion that we should suspend judgment
would make life unlivable. For, the business of day-to-day life
requires that we make choices and this requires making judgments.
Similarly, one might point out that our apparent success in
interacting with the world and each other entails that we must know
some things. Some responses by ancient skeptics to these objections
are considered in the following discussion.
(Hankinson [1995] is a comprehensive and detailed examination of
ancient skeptical views. See Schmitt [1972] and Popkin [1979] for
discussion of the historical impact of ancient skepticism, beginning
with its rediscovery in the 16th Century, and Fogelin [1994] for an
assessment of Pyrrhonian skepticism in light of contemporary
epistemology. The differences between ancient and modern forms of
skepticism has been a controversial topic in recent years-see
especially, Annas [1986], [1996], Burnyeat [1984], and Bett [1993].)
Table of Contents (Clicking on the links below will take you to those parts of this article)
1. The Distinction Between Academic and Pyrrhonian Skepticism
2. Academic Skepticism
a. Arcesilaus
i. Platonic innovator
ii. Attack on the Stoics
iii. On suspending judgment
iv. Dialectical Interpretation
v. Practical Criterion: to eulogon
b. Carneades
i. Socratic Dialectic
ii. On ethical theory
iii. On the Stoic sage
iv. On epistemology
v. Practical criterion: to pithanon
vi. Dialectical skeptic or fallibilist?
c. Philo and Antiochus
d. Cicero
3. Pyrrhonian Skepticism
a. Pyrrho and Timon
b. Aenesidemus
i. Revival of Pyrrhonism
ii. The Ten Modes
iii. Tranquility
c. Sextus Empiricus
i. General Account of Skepticism
ii. The path to skepticism
iii. The Modes of Agrippa
iv. Skepticism versus relativism
v. The skeptical life
4. Skepticism and the Examined Life
5. Greek and Latin texts, commentaries, and translations
6. Select Bibliography
1. The Distinction Between Academic and Pyrrhonian Skepticism
The distinction between Academic and Pyrrhonian skepticism
continues to be a controversial topic. In the Second Century C.E.,
the Roman author Aulus Gellius already refers to this as an old
question treated by many Greek writers (Attic Nights 11.5.6,
see Striker [1981/1996]). The biggest obstacle to correctly making
this distinction is that it is misleading to describe Academic and
Pyrrhonian skepticism as distinctly unified views in the first place
since different Academics and Pyrrhonists seem to have understood
their skepticisms in different ways. So even though the terms
Academic and Pyrrhonian are appropriate insofar as there are clear
lines of transmission and development of skeptical views that unify
each, we should not expect to find a simple account of the
distinction between the two.
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2. Academic Skepticism
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a. Arcesilaus
Following Plato's death in 347 B.C.E., his nephew Speusippus
became head of the Academy. Next in line were Xenocrates, Polemo and
Crates. The efforts of the Academics during this period were largely
directed towards developing an orthodox Platonic metaphysics. When
Crates died (c. 272 B.C.E.) Arcesilaus of Pitane (c. 318 to 243
B.C.E.) became the sixth head of the Academy. Another member of the
Academy, Socratides, who was apparently in line for the position,
stepped down in favor of Arcesilaus (DL 4.32); so
it seems he was held in high regard by his predecessors, at least at
the time of his appointment. (See Long [1986] for discussion of the
life of Arcesilaus.)
i. Platonic innovator
According to Diogenes
Laertius (=DL), Arcesilaus was
"the first to argue on both sides of a question, and the first to
meddle with the traditional Platonic system [or: discourse,
logos] and by means of question and answer, to make it more of
a debating contest" (4.28, translation after R.D. Hicks).
Diogenes is certainly wrong about Arcesilaus being the first to argue
on both sides of a question. This was a long standing practice in
Greek rhetoric commonly attributed to the Sophists. But
Arcesilaus was responsible for turning Plato's Academy to a
form of skepticism. This transition was probably supported by an
innovative reading of Plato's books, which he possessed and held in
high regard (DL 4.31).
Diogenes' remark that Arcesilaus 'meddled' with Plato's
system and made it more of a debating contest indicates a critical
attitude towards his innovations. Diogenes (or his source)
apparently thought that Arcesilaus betrayed the spirit of Platonic
philosophy by turning it to skepticism.
Cicero, on the other hand, in an approving tone, reports that
Arcesilaus revived the practice of Socrates, which he takes to
be the same as Plato's.
"[Socrates] was in the habit of drawing forth the opinions of those
with whom he was arguing, in order to state his own view as a
response to their answers. This practice was not kept up by his
successors; but Arcesilaus revived it and prescribed that those who
wanted to listen to him should not ask him questions but state their
own opinions. When they had done so, he argued against them. But
his listeners, so far as they could, would defend their own opinion"
(de Finibus 2.2, translated by Long and Sedley, 68J, see
also de Natura Deorum 1.11).
Arcesilaus had (selectively) derived the lesson from Plato's
dialogues that nothing can be known with certainty, either by the
senses or by the mind (de Oratore 3.67, on the topic of Plato
and Socrates as proto-skeptics, see Annas [1992], Shields [1994] and
Woodruff [1986]). He even refused to accept this conclusion; thus he
did not claim to know that nothing could be known (Academica
45).
ii. Attack on the Stoics
In general, the Stoics were
the ideal target for the skeptics; for, their confidence in the areas
of metaphysics, ethics and epistemology was supported by an elaborate
and sophisticated set of arguments. And, the stronger the
justification of some theory, the more impressive is its skeptical
refutation. They were also an attractive target due to their
prominence in the Hellenistic world. Arcesilaus especially targeted
the founder of Stoicism,
Zeno, for refutation. Zeno confidently claimed not only that
knowledge is possible but that he had a correct account of what
knowledge is, and he was willing to teach this to others. The
foundation of this account is the notion of katalêpsis:
a mental grasping of a sense impression that guarantees the truth of
what is grasped. If one assents to the proposition associated with a
kataleptic impression, i.e. if one experiences katalepsis, then the
associated proposition cannot fail to be true. The Stoic sage,
as the perfection and fulfillment of human nature, is the one who
assents only to kataleptic impressions and thus is infallible.
Arcesilaus argued against the possibility of there being any
sense-impressions which we could not be mistaken about. In doing so,
he paved the way for future Academic attacks on Stoicism. To
summarize the attack: for any sense-impression S, received by some
observer A, of some existing object O, and which is a precise
representation of O, we can imagine circumstances in which there is
another sense-impression S', which comes either (i) from something
other than O, or (ii) from something non-existent, and which is such
that S' is indistinguishable from S to A. The first possibility (i)
is illustrated by cases of indistinguishable twins, eggs, statues or
imprints in wax made by the same ring (Lucullus 84-87). The
second possibility (ii) is illustrated by the illusions of dreams and
madness (Lucullus 88-91). On the strength of these examples,
Arcesilaus apparently concluded that we may, in principle, be
deceived about any sense-impression, and consequently that the Stoic
account of empirical knowledge fails. For the Stoics were
thorough-going empiricists and believed that sense-impressions lie at
the foundation of all of our knowledge. So if we could not be
certain of ever having grasped any sense-impression, then we cannot
be certain of any of the more complex impressions of the world,
including what strikes us as valuable. Thus, along with the failure
to establish the possibility of katalepsis goes the failure to
establish the possibility of Stoic wisdom
(see Hankinson [1995], Annas [1990] and Frede [1983/1987] for
detailed discussions of this epistemological debate).
iii. On suspending judgment
In response to this lack of knowledge (whether limited to the
Stoic
variety or knowledge in general), Arcesilaus claimed that we should
suspend judgment. By arguing for and against every position that
came up in discussion he presented equally weighty reasons on both
sides of the issue and made it easier to accept neither side
(Academica 45). Diogenes counts the suspension of judgment as
another of Arcesilaus' innovations (DL4.28) and
refers to this as the reason he never wrote any books (4.32).
Sextus Empiricus (Outlines of Pyrrhonism [generally referred
to by the initials of the title in Greek, PH] 1.232) and Plutarch
(Adversus Colotes 1120C) also attribute the suspension of
judgment about everything to him.
Determining precisely what cognitive attitude Arcesilaus
intended by "suspending judgment" is difficult, primarily because we
only have second and third hand reports of his views (if indeed he
endorsed any views, see Dialectical Interpretation below). To
suspend judgment seems to mean not to accept a proposition as true,
i.e. not to believe it. It follows that if one suspends judgment
regarding p, then he should neither believe that p nor should he
believe that not-p (for this will commit him to the truth of not-p).
But if believing p just means believing that p is true, then
suspending judgment regarding everything is the same as not believing
anything. If Arcesilaus endorsed this, then he could not
consistently believe either that nothing can be known or that one
should consequently suspend judgment.
iv. Dialectical Interpretation
One way around this problem is to adopt the dialectical
interpretation (advanced by Couissin [1929]). According to this
interpretation, Arcesilaus merely showed the Stoics that
they didn't have an adequate account of knowledge, not that
knowledge in general is impossible. In other words, knowledge will
only turn out to be impossible if we define it as the Stoics do.
Furthermore, he did not show that everyone should suspend judgment,
but rather only those who accept certain Stoic
premises. In particular, he argued that if we accept the Stoic view
that the Sage never errs, and since katalepsis is not possible, then
the Sage (and the rest of us insofar as we emulate the Sage) should
never give our assent to anything. Thus the only way to achieve
sagehood, i.e. to consistently avoid error, is to suspend judgment
regarding everything and never risk being wrong (Lucullus
66-67, 76-78, see also Sextus Empiricus, Against the Logicians
[generally referred to by the initial M, for the name of the larger
work from which it comes, Adversus Mathematikos] 7.150-57).
But the dialectical Arcesilaus himself neither agrees nor disagrees
with this.
v. Practical Criterion: to eulogon
The biggest obstacle to the dialectical interpretation is
Arcesilaus' practical criterion, to eulogon. Arcesilaus
presented this criterion in response to the Stoic
objection that if we were to suspend judgment regarding everything,
then we would not be able to continue to engage in day to day
activities. For, the Stoics
thought, any deliberate action presupposes some assent, which is to
say that belief is necessary for action. Thus if we eliminate belief
we will eliminate action (Plutarch, Adversus Colotes 1122A-F,
LS 69A).
Sextus remarks that
"inasmuch as it was necessary . . . to investigate also the conduct
of life, which cannot, naturally, be directed without a criterion,
upon which happiness-that is, the end of life-depends for its
assurance, Arcesilaus asserts that he who suspends judgment about
everything will regulate his inclinations and aversion and his
actions in general by the rule of 'the reasonable [to
eulogon],' and by proceeding in accordance with this criterion he
will act rightly; for happiness is attained by means of wisdom, and
wisdom consists in right actions, and the right action is that which,
when performed, possesses a reasonable justification. He, therefore,
who attends to 'the reasonable' will act rightly and be happy"
(M 7.158, translated by Bury).
There is a good deal of Stoic
technical terminology in this passage, including the term eulogon
itself, and this may seem to support the dialectical
interpretation. On this view, Arcesilaus is simply showing the Stoics both
that their account of knowledge is not necessary for virtue, and that
they nonetheless already have a perfectly acceptable epistemic
substitute, to eulogon (see Striker [1980/1996]). But this
raises the question, why would Arcesilaus make such a gift to his Stoic
adversaries? It would be as if, Maconi's words, "Arcesilaus first
knocked his opponent to the ground and then gave him a hand up again"
(1988: 248). Such generosity would seem to be incompatible with the
purely dialectical purpose of refutation. Similarly, if he had been
arguing dialectically all along, there seems to be no good reason for
him to respond to Stoic
objections, for he was not presenting his own views in the first
place. On the other hand, the proponent of the dialectical view
could maintain that Arcesilaus has not done any favors to the Stoics by
giving them the gift of to eulogon; rather, this 'gift' may
still be seen as a refutation of the Stoic view
that a robust knowledge is necessary for virtue.
An alternative to the dialectical view is to interpret to
eulogon as Arcesilaus' own considered opinion regarding how one
may live well in the absence of certainty. This view then encounters
the earlier difficulty of explaining how it is consistent for
Arcesilaus to endorse suspending judgment on all matters while at the
same time believing that one may attain wisdom and happiness by
adhering to his practical criterion.
Back to Table of Contents
b. Carneades
Arcesilaus was succeeded by Lacydes (c. 243 B.C.E.), and then
Evander and Hegesinus in turn took over as heads of the Academy.
Following Hegesinus, Carneades of Cyrene (c. 213 to 129 B.C.E.),
perhaps the most illustrious of the skeptical Academics, took charge.
Rather than merely responding to the dogmatic positions that were
currently held as Arcesilaus did, Carneades developed a wider array
of skeptical arguments against any possible dogmatic position,
including some that were not being defended. He also elaborated a
more detailed practical criterion, to pithanon. As was the
case with Arcesilaus, he left nothing in writing, except for a few
letters, which are no longer extant (DL 4.65).
i. Socratic Dialectic
Carneades employed the same dialectical strategies as
Arcesilaus (Academica 45, Lucullus 16), and similarly
found his inspiration and model in Plato's Socrates. The Socratic
practice which Carneades employed, according to Cicero, was to try to
conceal his own private opinion, relieve others from deception and in
every discussion to look for the most probable solution (Tusculan
Disputations 5.11, see also de Natura Deorum 1.11).
In 155 B.C.E., nearly one hundred years after Arcesilaus' death in
243, Carneades is reported to have gone as an Athenian ambassador to
Rome. There he presented arguments one day in favor of justice and
the next he presented arguments against it. He did this not because
he thought that justice should be disparaged but rather to show its
defenders that they had no conclusive support for their view
(Lactantius, LS 68M). Similarly, we find Carneades arguing against
the Stoic
conception of the gods, not in order to show that they do not exist,
but rather to show that the Stoics had
not firmly established anything regarding the divine (de Natura
Deorum 3.43-44, see also 1.4). It seems then that Carneades was
motivated primarily by the Socratic goal of relieving others of the
false pretense to knowledge or wisdom and that he pursued this goal
dialectically by arguing both for and against philosophical positions.
ii. On ethical theory
But whereas Arcesilaus seemed to limit his targets to
positions actually held by his interlocutors, Carneades generalized
his skeptical attack, at least in ethics and epistemology. The main
task of Hellenistic ethics was to determine the summum bonum,
the goal at which all of our actions must aim if we are to live
good, happy lives. Carneades listed all of the defensible
candidates, including some that had not actually been defended, in
order to argue for and against each one and show that no one in fact
knows what the summum bonum is, if indeed there is one (de
Finibus 5.16-21). He may have even intended the stronger
conclusion that it is not possible to acquire knowledge of the
summum bonum, assuming his list was exhaustive of all the
serious candidates.
iii. On the Stoic sage
As with Arcesilaus, Carneades also focused much of his
skeptical energy on the Stoics,
particularly the views of the scholarch Chrysippus (DL 4.62).
The Stoics
had developed a detailed view of wisdom as life in accordance with
nature. The Stoic sage
never errs, he never incorrectly values the goods of fortune, he
never suffers from pathological emotions, and he always remains
tranquil. His happiness is completely inviolable since everything he
does and everything he experiences is precisely as it should be; and
crucially, he knows this to be true. Even though the Stoics were
extremely reluctant to admit that anyone had so far achieved this
extraordinary virtue, they nonetheless insisted that it was a real
possibility (Luc. 145, Tusc. 2.51, Seneca Ep.
42.1, M 9.133, DL 7.91).
As a dialectician, Carneades carefully examined this
conception of the sage. Sometimes he argued, contrary to the Stoic view,
that the sage would in fact assent to non-kataleptic impressions and
thus that he was liable to error (Luc. 67); for he might form
opinions even in the absence of katalepsis (Luc. 78). But he also
apparently argued against the view that the sage will hold mere
opinions in the absence of katalepsis (Luc. 112). Presumably
he didn't himself endorse either position since the issue that had to
be decided first was whether katalepsis was even possible. In other
words, if certainty is possible, then of course the sage
should not settle for mere opinion. But if it is not possible, then
perhaps he will be entitled to hold mere opinions, provided they are
thoroughly examined and considered.
iv. On epistemology
Just as Carneades generalized his skeptical attack on ethical
theories, he also argued against all of his predecessors'
epistemological theories (M 7.159). The main task of
Hellenistic epistemology was to determine the criterion (standard,
measure or test) of truth. If the criterion of truth is taken to be
a sort of sense-impression, as in the Stoic
theory, then we will not be able to discover any such impression that
could not in principle appear true to the most expertly trained and
sensitive perceiver and yet still be false (M 7.161-65, see
Arcesilaus' |
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