What Does Academic Skepticism Presuppose?
What Does
Academic Skepticism Presuppose?
Arcesilaus, Carneades, and the Argument with Stoic Epistemology
David
Johnson
Although
some have seen the skepticism of Arcesilaus and
Carneades, the two foremost representatives of Academic philosophy, as
being merely
dialectical in nature, there is evidence that both philosophers held
views
definitive of their skepticism, views which are a direct consequence of
a
critique of Stoic epistemology and of a defense against the Stoic
argument from
apraxia. Moreover, both the critique
and defense are articulated within the framework provided by Stoic
epistemology. There
is a strong case,
then, to be made for the claim that Academic skepticism cannot stand
alone,
that it necessarily requires the terms, concepts and assumptions of
Stoicism as
an antecedent condition. In making this case I will treat the views of
Arcesilaus and Carneades separately, since there are some important
differences
between them.
In
order to see the way in which Arcesilaus presupposes dogmatic
philosophy, we
first have to address the question of whether the skepticism of
Arcesilaus was
merely dialectical, or whether he held definitive skeptical views of
his own.
If Arcesilaus was a dialectician who limited himself to arguing against
the
views of others without proposing any of his own, then his skepticism
would
only presuppose the existence of opponents holding dogmatic views.
Although his
dialectical method could not subsist on its own, then, there is no
reason why
it should necessarily require as dialectical fuel the particular form
of
dogmatism found in Stoic philosophy. If, on the other hand, as I want
to
maintain, Arcesilaus held the three interrelated views that nothing can
be
known, that all people ought to suspend judgment, and that one can use
the eulogon, or reasonable, as a
practical
criterion to guide action, then these views would be parasitic on Stoic
philosophy in particular. The first two views presuppose Stoic
philosophy
because they are the consequence of a critique of Stoic epistemology.
The third
view presupposes Stoicism first, because it seems to have been
developed as a
response to the Stoic charge of apraxia,
and second, because this defense is articulated using the terminology
of, and
within the framework provided by, Stoic epistemology.
The
evidence that Arcesilaus was simply a dialectician is thin. According
to
Numenius
He [Arcesilaus] did not
have it in him ever to express one and
the same position, nor, for that matter, did he think such a thing
worthy of a
shrewd man. And that is why he was called “a clever sophist, cutthroat
of
novices.” […] He would not allow that he or anyone else was in a
position to
know anything […] but he would say whatever came into his head and then
immediately reversing himself he would knock down that view in more
ways than
he had used to set it up.
But,
as R.J. Hankinson notes, Numenius is a hostile source.
Moreover, Arcesilaus is described here as holding the view that nothing
can be
known, something that would be in tension with the interpretation of
him as
simply an eristic philosopher. And although Diogenes Laertius also
presents
Arcesilaus as a dialectician, Arcesilaus is described once again as
holding a
view, in this case the view that one ought to suspend judgment—a claim he repeats elsewhere (DL, 4.32) and one that is echoed by
Sextus (Outlines of Pyrrhonism, 1.232).
He
describes Arcesilaus as
the first to suspend
[making] assertions because of the
contradictions among arguments. He was also the first to argue both
sides of a
question and the first to change the doctrine handed down by Plato,
that is, to
make it more eristic by the use of question and answer…
Cicero,
on the other hand, asserts that Arcesilaus was no mere dialectician and
that it
was necessary for the wise man to hold views:
…Arcesilaus did not fight
with Zeno for the sake of quarrelling
but really wanted to discover the truth. None of his predecessors ever
formally
claimed […] that it was possible for a man to hold no opinions, while
it was
not only possible but even necessary for a wise man to do so.
Arcesilaus
thought that this view was true, and respectable and worthy of a wise
man.
Moreover,
he informs us that Arcesilaus held the view that
that one should suspend judgment as a consequence of his holding the
view that
nothing could be known:
So, Arcesilaus denied that
there was anything that could be
known […] he judged everything to reside in darkness and that nothing
could be
discerned or understood. For these reasons, one should neither profess
nor
affirm nor give approval with assent to anything...
I want
to agree with Cicero
that Arcesilaus was not an eristic philosopher, but that he held the
two
positive, interrelated views that one should suspend judgment because
nothing
can be known. These views are the consequence of Arcesilaus’ critique
of Stoic
epistemology, an epistemology that rests on an empirical theory of
perception.
According to this theory, perception takes place when a perceiver’s
organs of
sense perception come into contact with the object of perception
through a
presentation, which is an impression that an object makes on the soul (M
7.228)
that is indicative of both itself and the object which produces it (M 7.161). This is an empirical theory of
perception that defines perceiving as being affected materially in the
soul by
the object perceived.
The
Stoic theory of knowledge builds on this model of perception by first
making a
qualitative distinction between accurate and inaccurate impressions,
which they
term graspable and non-graspable presentations, respectively. A
graspable
presentation is a stimulus or impression coming from an existing object
outside
of the subject that is a reliable representation of the object because
it is
“stamped and molded in accordance with the existing object”. A
non-graspable
presentation either does not come from an existing object, or is not
clear and
distinct (D.L., 7.46, Acad.,
1.40). When a graspable
presentation has been received and approved by the subject, i.e.,
assented to,
then it has been grasped. A grasped presentation, because is accurate
and
reliable and leaves out nothing about the object that can be grasped
through
sensible perception, is the criterion of knowledge, but it not yet
knowledge
itself. Rather, a grasped presentation lies between knowledge and
ignorance; it
is one step on the way to knowledge. Zeno illustrated this point with
the
simile of a hand. A presentation is like an open hand, assent is like a
half-closed hand, grasping is like a closed fist, and knowledge is like
a hand
over a closed fist. Knowledge is a firmly
grasped presentation that cannot be shaken or reversed by argument (Acad., 1.41-42).
Arcesilaus’
response to this theory of knowledge was to claim that there is no such
thing
as a graspable presentation—and thus, no criterion of knowledge (Acad. 2.77). Since there is no criterion
of knowledge, nothing can be known. And if nothing can be known, we
must
suspend judgment. These conclusions are presented in two separate
arguments.
The first argument can be found in Cicero,
Acad. 2.40:
1) Some presentations are
true, some are false
2) False presentations cannot be grasped
3) There is no true presentation such that there cannot be a false one
of the
same quality
4) No presentation can be grasped if there is no criterion for
distinguishing
between true and false presentations
5) Therefore, there are no graspable presentations
The
entire argument turns on the third premise. The point of
this premise is that whatever one might say about the reliability of a
graspable presentation—that it compels assent because it has a vivacity
or “a
distinctive kind of clear statement to make about the objects of
presentation”
(Acad. 1.41) that is, as Charlotte
Stough phrases it, “of such a nature as to have originated necessarily
in that
object of which it is in fact the exact replica,”
there are many presentations that come from non-existing objects that
also meet
these criteria, such as hallucinations, dreams, illusions, and
impressions that
are caused by our limited sensory powers rather than by the object
itself.
The implications of this argument for the Stoic theory of knowledge are
made
clear in a second argument, found in Sextus, M,
7.156-57:
1) Everything is ungraspable
because there is no criterion of knowledge
2) If the wise man assents to anything, he will assent to the
ungraspable
3) Assent to the ungraspable is opinion
4) The wise man does not opine, so the wise man will not assent to
anything
5) Refusal to give assent is the suspension of judgment
6) Therefore, the wise man suspends judgment
One
might argue at this point that the skeptic has only demonstrated that
the Stoic
is forced, by his own principles, to conclude that nothing can be
known, and
hence that he is trapped by his own epistemology into suspending
judgment about
everything, rather than that nothing can be known in a more global
sense, and
that everyone ought to suspend judgment. If this were the case, then
one might
still be able to argue that Arcesilaus was a dialectician who, through
a reductio ad absurdum, forced the
Stoic
philosopher into accepting unpalatable conclusions, conclusions that
Arcesilaus
himself need not have accepted. However, as Charlotte Stough points
out,
Academics accept the Stoic account of perception as the soul being
affected or
altered by impressions made by external objects.
Since this theory of perception is, as I noted earlier, the basis for
Stoic
epistemology, this limits the skeptic to an empirical psychology as the
only
possible epistemological framework within which to given an account of
how a
human being comes to know something. Therefore, Arcesilaus’ critique of
Stoic
epistemology is implicitly a critique of the possibility of knowledge
in
general, and the conclusions he reaches must have been intended to have
a wider
application than merely to the philosophy of Stoicism.
After showing that nothing can be
known and that as a result we must suspend judgment, Arcesilaus seems
to have
been attacked by the Stoics as putting forward views that make it
impossible to
act, since, on their view, action requires knowledge:
…There must be a principle
which wisdom follows when it begins
to do something and this principle must be according to nature. For
otherwise
impulse […] by which we are driven to act and pursue what is presented,
cannot
be stimulated. But that which stimulates must first be presented [to
the agent]
and it must be believed; and this cannot happen if what is presented
cannot be
distinguished from what is false. For how can the mind be moved to an
impulse
if there is no judgment as to whether what is presented in according to
nature
or contrary to it? Similarly, if the mind does not realize what is
appropriate
to it, it will never do anything at all, will never be driven to
anything, will
never be stimulated. But if it is ever to be moved, what occurs to the
agent
must be presented as being true.
For
those who hold to such a theory of action, the view that
we must suspend judgment because nothing can be known was vulnerable to
the
argument from apraxia:
…Not even those who
concerned themselves a great deal with this
matter […] were able to shake the doctrine of suspension of judgment on
all
questions. But at last the Stoics brought against it like a Gorgon’s
head the
“argument from inaction” and then gave up.
The
Stoic charge that the skeptic is not able to act is additional evidence
that
Academic skepticism was more than simply dialectical in nature, as it
presupposes that the skeptics themselves did indeed hold the view, as I
am
claiming, that since nothing can be known, one must suspend judgment.
Arcesilaus’ response to the Stoic attack was to propose
‘reasonableness’ as a
practical criterion for the conduct of life. Those who adhere to the
reasonable
will be able to act correctly and attain happiness (M
7.158). The skeptics overcame the problem of how one can follow
what is reasonable or plausible while still suspending judgment by
making a
distinction between assent, which would entail that one had ceased
suspending
judgment, and impulse, which enables a person to act without holding a
view
about whether a particular presentation is true.
They maintained that a presentation awakens
an impulse, which “moves man to act with respect to what is appropriate
for
him.”
An impulse is a movement of the soul caused by a presentation, a
process
compared to the tipping of a scale. This solution to the problem
presupposes
Stoic philosophy because it is a response to a Stoic attack; it also
presupposes Stoicism insofar as the specific content of that
response—i.e., a
description of the relationship between the three movements in the soul
of
presentation, impulse, and assent—relies on the terms and assumptions
of Stoic
epistemology.
The
case of Carneades is essentially a variation on the way in which
Arcesilaus
presupposes Stoic philosophy. Carneades, too, was no mere a
dialectician; he
also held the view that nothing can be known (Acad.
2.59, 78, 148) because “there is no true presentation such
that there could not be a false one just like it.”
As in the case of Arcesilaus, we can attribute this view to Carneades
because
(in addition to the textual evidence cited above which indicates that
he held
this view) he, like everyone, will be forced to hold the view that
nothing can
be known as the result of a critique of an epistemology assumed to be
the only
possible account of knowledge, an assumption Carneades must make, since
he
shares the Stoic theory of perception. As with Arcesilaus, Carneades’
claim
that nothing can be known presupposes Stoicism because it results from
a
critique of Stoic epistemology.
Since
Carneades held that nothing could be known, when “asked for some
criterion for
the conduct of life and for the attainment of happiness,” he was
“virtually
compelled to take a position for himself on the topic” (M,
7.166). This looks very much like the old Stoic charge that the
skeptic will not be able to act. Although Carneades also responded to
this
charge by maintaining with Arcesilaus that knowledge is not necessary
for
action, he differed from Arcesilaus in explaining what exactly was necessary. Whereas Arcesilaus had
argued that assent to presentations was not needed to act, because the
reasonable or plausible would enable a person who has suspended
judgment to
live by eliciting the impulse to action, Carneades thinks that we will
need to
assent to the plausible presentation or pithanon
in order for it to guide action. I think it is important to note that pithanon seems likely to be a criterion
for action rather than for knowledge, or for both knowledge and action,
since
Carneades holds that everything is non-apprehensive or ungraspable, so
it is
not clear how the pithanon could
be a
criterion of knowledge. For this reason I don’t think that one can say
that
Carneades was presenting a positive doctrine or theory of knowledge to
replace
the Stoic theory. Instead, his doctrine of the pithanon
should be seen as a direct response to a Stoic attack.
Carneades
relies on the most basic concepts and assumptions of Stoic epistemology
in
constructing a counter to the Stoic argument from apraxia.
He accepts the idea that the truth of a presentation
consists in its correspondence with the object. What he rejects is the
possibility that one can inspect the object and its presentation in
such a way
as to determine whether there is a correspondence between the object
and the
presentation. All that can be known is whether the presentation appears to the subject having the
presentation that it is true (M,
7.167-69), such a presentation he calls an apparently true
presentation. An
apparently true presentation that is not obscure and seems very
intensely to be
apparently true is called a plausible presentation, or pithanon
(M, 7.171-73).
Carneades thinks that we
only need to suspend judgment about the truth of a presentation, but
not about
its apparent truth (Numenius in Prep. Ev.,
bk. xiv, ch. vii-viii, 736d); he maintains that we can give qualified
assent to
what is plausible. Academic assent to a plausible presentation is
weaker than
Stoic assent to a graspable presentation, since we can never know if
the apparently
true presentation is actually true, we cannot give unqualified assent
to
it—there is always the possibility that we may be wrong.
Nevertheless, the plausible presentation justifies our giving qualified
assent
and so can serve as a criterion for action (Acad.,
2.99).
The
strength of our assent or conviction will vary with the plausibility of
the
presentation,
since the plausibility of a presentation can vary in its degree of
plausibility. The first way a presentation can vary in it plausibility
is in
the way that it is given to us, that is, in the extent to which it
appears to
be a true and adequate representation of the object to the subject.
Some
plausible presentations, due to the intensity of their apparent
truthfulness,
strike a person as more plausible than others (M,
7.173). The second way that a presentation can vary in its
plausibility is as the result of the application of criteria to
determine the
degree of plausibility. A presentation becomes more plausible if it is
discovered to cohere with other presentations that are given along with
it. Sextus
observes that just as doctors do not judge someone to be feverish
without a
combination of symptoms, we can better judge the plausibility of a
single
presentation by examining the combination of presentations with which
it
appears, since presentations are never isolated. For example, the
presentation
of a person will increase in plausibility if that person’s attributes
and
external circumstances are also found to match or be in harmony with
the
presentation (M, 7.176-9). A
presentation achieves the highest degree of plausibility if it both
coheres
with other presentations and is subjected to, and passes, thorough
scrutiny. A
thoroughly tested presentation is one in which a combination of
presentations
is rigorously scrutinized in terms of the context in which it appears.
This
includes an examination of factors such as who is judging the
presentation and
the conditions that might influence the judgment of this person, the
medium in
which the judgment takes place, and the manner in which the judgment is
made (M, 7.182-3). Finally, the
extent to
which one will attempt to establish assent or conviction will depend on
the
seriousness of the matter at hand, and on whether circumstances permit
one to employ
all of the criteria listed above to determine the degree of assent or
conviction (M,
7.184-5).
Carneades’
concept of the pithanon presupposes
Stoicism in the same general way that Arcesilaus’ argument for impulse
did. The
pithanon is also a response to an
(implicit) Stoic attack from apraxia,
and the content of that response depends on the ideas and language of
Stoic
epistemology; we saw that Carneades used the structure of a
representationalist
epistemology in showing that a plausible belief is like knowledge in
being a
presentation, though it does not actually qualify as knowledge because
it is a
presentation without the truth content.
I hope
I have shown that Academic skepticism, for all of its nuance and power,
depends
in crucial ways on the philosophical assumptions, terms, and claims of
Stoicism
and that it is impossible to imagine a self-standing version of
Academic
skepticism that did not presuppose the philosophical constructs of
Stoicism. An
interesting consideration, then, is what, if anything, remains of
Academic
skepticism if one does not accept the representationalist assumptions
of Stoic
epistemology—though one doubts that it was possible conceptually or
imaginatively for Hellenistic philosophers to even raise this question.
Pennsylvania State University
University Park,
Pennsylvania
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