## 1. Life and work



Born in Cyrene, then a Greek-speaking city on the Mediteranean coast
of North Africa, Carneades pursued his philosophical studies in
Athens, which was then as it had been and was to be for some time the
philosophical center of the ancient world. There he studied not only
at the Academy, the school founded by Plato of which he was to become
the leader or scholarch, but also with with Diogenes of Babylon, the
fifth scholarch of the Stoic school and a pupil of Chrysippus (c.
208-206 BCE). Chrysippus was the principal architect of the
Stoic system and the most important philosophical stimulus to
Carneades, who is reported to have said, 'If Chrysippus had not
been, I would not have been' (D.L. 4.62) (which echoes the
saying, 'If Chrysippus had not been, there would have been no
Stoa'). Carneades became scholarch of the Academy sometime
before 155 BCE, when, together with Diogenes and Critolaus, the head
of Aristotle's school, the Peripatos, he was sent to Rome to
represent Athens in a petition before the senate (see Powell,
2013).



According to tradition, Carneades also delivered a pair of lectures
while in Rome, speaking in defense of justice on one day and, in
rebuttal of his own arguments of the previous day, against it on the
following day. This celebrated episode is recounted or alluded to in a
number of ancient sources, all of them much later, and doubts about
every part of the story including the reality of the lectures
themselves have been raised (see Drecoll, 2004; Powell, 2013). The
speech of Philus in the only partially extant third book of
Cicero's *De Republica* may preserve traces of
Carneades' speech against justice, though it is a matter of
controversy if and to what extent it does, or failing that it may draw
on arguments that Carneades made on other occasions (see Ferrary,
1977; Glucker, 2001).



Like Arcesilaus (316/15-241/40 BCE), the head of the Academy who
was responsible for the school's so-called 'skeptical
turn', and Socrates before him, Carneades wrote nothing, but
made his mark through face to face teaching and argument (D.L. 4.65).
The influence he exerted in this way was immense. From the time of his
scholarchate until the dissolution of the Academy under its probably
last leader, Philo of Larissa (159/8-84/3 BCE), philosophical
activity in the Academy and among the philosophers in its orbit
consisted in good part in the further development of ideas and lines
of argument pioneered or substantially reshaped by Carneades. Indeed
these philosophers often put forward their own views in the guise of
interpretations of Carneades. We are ultimately indebted for what we
know about him to works by those with firsthand experience of him,
especially Clitomachus, his student and eventual successor as
scholarch. Although none of the latter's many books has
survived, they were used by authors like Cicero (106-43 BCE) and
Sextus Empiricus (probably 2nd or 3rd century CE), whose works have
come down to us. (Greek and Latin testimonies are collected in Mette,
1985; many important passages with an English translation and notes
can be found in Long and Sedley, 1987.)


## 2. Epistemology and Academic Skepticism


### 2.1 Academic Skepticism



Histories of philosophy typically speak, as I did above, of a
'skeptical turn' in the Academy or of the 'skeptical
Academy'. Ancient authors called the school of Arcesilaus and
his successors the 'New Academy' to distinguish it from
the 'Old Academy' of his predecessors. Some cautions and
qualifications are in order, however. The term 'skeptic'
was not used by the Academics, but was the most prominent of several
descriptions bestowed on themselves by the members of the Pyrrhonian
school. It was applied only later to the Academics on the basis of a
long-recognized affinity between the two schools. In the original
meaning of the term, a skeptic is an inquirer or investigator, but it
came to be associated in particular with theses calling into question
the possibility of knowledge and recommending suspension of judgment
together with the arguments put forward in support of them. The sense
of 'skeptic' and 'skeptical' most familiar to
us has its origin in this use of the term. There is a corresponding
tension in accounts of the Academy, and in the philosophical activity
they seek to describe. 



This activity took the form of argument on both sides of the question
(*in utramque partem*). The speeches for and against justice
that Carneades delivered during the philosophers' embassy to
Rome was an instance. Most often, however, Academics in this period
left the defense of a theory to its proponents and argued against it,
creating an opposition in this way. The Academy's method of
argument was, in the first instance, dialectical, like that of
Socrates in Plato's Socratic dialogues. An argument is
dialectical in the relevant sense when one party, the questioner, puts
questions to another, questions that when affirmed by the answerer
become premises in an argument to a conclusion that contradicts a
thesis of the answerer's. This conclusion, deduced as it is from
premises chosen by the questioner because the answerer is committed to
them or will otherwise find them hard to resist, is not one to which
the questioner need be committed *in propria persona*. In
drawing them out, he remains detached, uncovering difficulties
internal to his interlocutor's position without committing
himself to a position of his own. The side usually taken by the
Academics in epistemological debates was that of the skeptic, in the
sense of one who challenges the possibility of knowledge.



There are numerous testimonies to the effect that the Academics
regarded argument on both sides of the question as a method of
inquiry, and argued as they did the better to discover the truth,
i.e., to further skeptical ends in the original acceptance of the term
(cf. Cicero, *Acad.* 2.7. 60, 76; *N.D.*1.11; Plutarch,
*Stoic. Repugnan.* 1037C). But opposing arguments to each other
can be also be used to lend support to skepticism in the sense of a
skeptical *position* by calling the possibility of knowledge
into question and commending the suspension of judgment. And sometimes
the Academics are said to have created such oppositions with this end
in view, i.e., it seems, to support a skeptical position to which they
were committed (Cicero *Acad.* 1.46). And a set of arguments
directly to the-in our sense-skeptical conclusions that
nothing can be known and that one should suspend judgment occupied a
place of central importance in the Academy's practice of
argument. The Academics seemed to their opponents to be attached to
the skeptical conclusions of these arguments. And this seems to have
been true of at least some Academics. Nonetheless these arguments seem
at least at first and in the hands of some New Academics to have been
put forward in a dialectical spirit.



The principal target of the arguments was the epistemology of the
Stoics, and it was out of their engagement on that front that the form
of the skeptical position defended by the Academics first emerged. The
Stoics maintained that it is possible for human beings to achieve a
condition of wisdom entirely free of opinion, i.e., false or insecure
belief. According to them, all of a wise human being's judgments
are instances of knowledge, based on an unshakable grasp of the truth.
Knowledge of this kind was possible according to them because there
exist so-called cognitive impressions (*kataleptikai
phantasiai*), which function as the criterion of truth (cf. Frede,
1999; Sedley, 2002). A cognitive impression they define as an
impression from what is, stamped and impressed in exact accordance
with what is, and such as could not be from what is not. This seems to
mean, in the paradigm case of a perceptual impression, that it is an
impression that arises in conditions which:


1. Ensure that, by capturing its object with perfect accuracy, it is
true, and


1. At the same time impart to it a clarity and distinctness that
belong only to impressions that arise in these conditions.



According to the Stoics, by restricting one's assent in the
perceptual sphere to impressions of this kind, one can avoid ever
assenting to a false perceptual impression, a key necessary condition
if one is to attain knowledge. As the criterion of truth, cognitive
impressions are the ultimate basis of all knowledge, by confining
one's assent to which, and meeting certain further conditions,
the Stoics maintained, one can avoid error and opinion entirely.



The Academics appealed to the skeptic's stock in trade, dreams,
madness, optical illusions and divinely inspired visions, in order to
argue that the special character allegedly proper to cognitive
impressions was not in fact peculiar to impressions produced in the
required truth-guaranteeing way, but could also be found in false
impressions (Cicero, *Acad.* 2.49-54, 79-82,
88-90; Sextus Empiricus, *Adversus mathematicos*
[henceforwad S.E. *M*] 7.402-8 = Long and Sedley
[henceforward L&S] 40H). If so, impressions that arise in the
specified conditions, though true, will be indistinguishable from
false impressions--so far as any intrinsic, discriminable
character is concerned. Therefore they will not be cognitive, and not
being cognitive, they will not be able to serve as a criterion. That
there are no cognitive impressions is the first of the two
propositions most closely associated with ancient skepticism. And
since it then follows, on Stoic assumptions, that nothing can be
known, this was often taken to be equivalent to the claim that nothing
can be known. The second skeptical proposition, that one ought to
suspend judgment, the Academics deduced from the first together with
the Stoic doctrine that the wise do not hold (mere) opinions (S.E.
*M* 7.155-7 = L&S 41C). On Stoic assumptions, assent
to an impression that is not cognitive (either in the strict sense or
in a broader sense which covers impressions that, though not
perceptual, nonetheless afford an equally secure grasp of their
contents), is sufficient to make the resulting judgment an opinion.
Therefore, in the absence of cognitive impressions, one can avoid
opinion only by suspending judgment entirely.



On a strictly dialectical interpretation, the skeptical propositions
for which the Academics argued need not tell us anything about what
philosophical views, if any, they accepted themselves. The skeptical
position that comprises these two claims--that knowledge is not
possible and that one ought to suspend judgement about
everything--is an unwelcome consequence of Stoic views and
presents the Stoics with a problem that it is their responsibility to
solve, not the Academy's.



To be sure, Arcesilaus and other Academics, Carneades above all,
defended the possibility of a life without knowledge and without
assent (Plutarch, *Adversus Colotem* 1122A-F = L&S]
69A). But that need not show that they somehow held a skeptical
position. Instead their aim may have been to counter the Stoic charge
that the Academic arguments for the skeptical propositions must be
faulty because they render rational action impossible. And
Arcesilaus' account of how one can act in the absence of
knowledge and without assent is so heavily dependent on Stoic
doctrines that it looks very much like an effort to show the Stoics
that their system already contained the resources necessary to explain
how action was possible for the skeptic as envisaged in the
Academy's arguments.



Nevertheless, there is evidence that at some stage in the
school's history, even if they did not use the term
'skeptic', some Academics were skeptics in the sense that
they adopted one or both of the two skeptical propositions as the
correct philosophical position *in propria persona*. Whether
Carneades endorsed a positions of his own and, if so, which ones is
unclear and was already a matter of dispute in the Academy. He is
known to have championed different positions on the same question in
different contexts. It is plain nonetheless that he prepared the way
for his successors to take this step (see below).



Later ancient writers sometimes speak of Carneades founding the third
or New Academy (giving 'New Academy' which elsewhere
covers the whole of the Academy from Arcesilaus' time a narrower
meaning) which followed the second or Middle Academy of Arcesilaus and
the first or Old Academy of Plato and his earliest successors. (The
distinction between Academies was meant to signal changes in
philosophical doctrine or approach, not changes in the school as an
institution.) The New Academy in this narrower sense seemed, to both
ancient philosophers and modern historians, to differ from the Middle
chiefly in two respects. Carneades appeared to favor a mitigated form
of skepticism, which admitted the possibility of well-founded opinions
if not of certain knowledge. And he tackled issues in, and sometimes
defended positions about, logic, ethics, natural philosophy and
theology as well as epistemology, which had been the focus of
Arcesilaus' attention. 



It is likely that Carneades refined and added to the stock of
skeptical arguments employed in the Academy. They come in two groups.
The first focus on the allegedly peculiar character, a kind of
clarity, and strikingness, that belongs only to impressions that arise
in the way specified by the definition of the cognitive impression,
while the second tackle the requirement that cognitive impressions be
distinct (*Acad*. 2.54-8, 84-6; S.E. *M*
7.408-11 = L&S 40H). Arguments of the second type are based
on the idea, denied by the Stoa, that two object might be exactly
alike. If this were true, then even if impressions that captured their
objects with complete accuracy by arising in the specified ideal
conditions did possess a clarity that it was possible to acquire in no
other way, it would not be possible to avoid errors of identification
by confining one's assent to impressions with the required
clarity. One could, for instance, mistake someone for his identical
twin. The only sure way to avoid error would then be to suspend
judgment.


### 2.2 Probabilism



The contribution for which Carneades is best known, however, came in
reply to the Stoics' counter-argument in defense of the
cognitive impression. In response to their contention that, without
cognitive impressions, human beings would lack any basis for action or
inquiry Carneades argued that such a basis could be found in so-called
probable impressions (from *probabilis*, that which lends
itself to or invites approval, Cicero's Latin for Greek
"pithanos," persuasive) (see Allen, 1994; Obdrzalek, 2006;
Reinhardt, 2018). The theory of probable impressions went far beyond
anything Arcesilaus had said and had an independent appeal which
Arcesilaus' response to the same challenge lacked.
Carneades' defense of this theory is a main reason why he was
thought to have departed from or moderated the stricter skepticism
thought to have been espoused by Arcesilaus and the Middle Academy
(S.E. *Pyrrhoneae hypotyposes* [henceforward *PH*]
1.227-30; *M* 7.166-89 = L&S 69DE). It seemed
to be complemented by the line he sometimes defended on opinion, and
that some of his successors took for his considered opinion, according
to which assent to non-cognitive impressions and the opinions to which
it gives rise are compatible with wisdom (*Acad.* 2.59, 67,
78). But the interpretation of Carneades championed by Clitomachus,
according to which the wise will refrain from assent and so avoid
opinion, also relied on probability as the basis for an alternative
form of approval (*Acad.* 2.99-100, 104-3).



Carneades' defense of probabilism can also be viewed, at least
in the first instance, as a natural extension of the Academy's
tradition of dialectical argument, however. The epistemological debate
between the Stoa and the Academy extended over many years and was
conducted with a great deal of energy and ingenuity on both sides. It
tended toward impasse. If the burden of argument fell entirely upon
the Academy and the its members were restricted to premises that were
strictly implied by Stoic theory, the Academic case was not proven.
The Stoics were not required on pain of self-contradiction to accept
all the premises the Academics needed. Nonetheless, by rejecting these
premises, the Stoics often committed themselves to highly disputable
contentions. This mattered to them, because their aim was not simply
to vindicate the internal consistency of their system. They claimed
that their views were true and uniquely consistent with common
conceptions held by all human beings.



In effect, the Stoics claimed that no position apart from theirs could
do justice to a set of considerations that were not peculiar to their
school but were accepted by everyone. It should, then, be possible for
them to convince open-minded and intelligent auditors of the truth of
Stoicism. The challenge that Carneades accepted was to show that there
were alternatives which could do justice to the agreed upon
considerations as well as or better than did the Stoic position, while
dispensing with its most distinctive and contentious features. Though
it does not restrict itself to premises that are already Stoic
doctrines, this form of argument is broadly dialectical. By aiming to
do justice to the considerations which the Stoics agree are relevant
to the area in question, and directing his arguments to intelligent
and open-minded auditors whom they are committed to taking seriously,
Carneades, perhaps among other things, was trying to show the Stoics
that their position did not satisfy the standards they set for
themselves. Because the theories he put forward and defended to this
end are not based solely on Stoic doctrines, they sometimes have a
wider appeal, and it is easier to attribute them to their author.
Nonetheless, though they are Carneades' in the sense of being
his creations, they need not have expressed his convictions.



In keeping with this style of argument, Carneades prepared the way for
his theory of probability by setting out an epistemological framework
which, though obviously indebted to Stoic views, was intended to
capture intuitions that were more widely shared. In this broadly
foundationalist framework it is natural to look for a criterion of
truth where the Stoics and other Hellenistic philosophers do, viz.
among self-evident impressions of sense (S.E. *M*
7.159-65 = L&S 70A). Yet the Academy's arguments
against cognitive impressions seem to have shown that no such
impressions are to be found. With the aid of his account of
probability, Carneades undertook to show that, after all, they are not
needed. Rational action and inquiry are possible without the
foundation that cognitive impressions promised to provide because
probable impressions can serve in their place. And if this is right,
or if it is sufficiently plausible, the Stoics' attempt to
provide indirect support for their contentions about the cognitive
impression by showing that there are no satisfactory alternatives will
fail.



The account of probability explains how one can discriminate among
impressions by investigating whether an initially persuasive
impression agrees with one's other impressions or if there is
something about the conditions in which it arose that undermines
confidence in it. The more such checks it survives, the more
confidence one will have in it. Depending on the amount of time
available and the importance of the matter in question, it is possible
to perform more or fewer of them. Although no amount of checking is
sufficient to eliminate any chance of error, it is possible to achieve
the degrees of confidence required in different circumstances to make
rational action and theoretical inquiry possible (*Acad.* 2.32,
110). Carneades' theory is thus an early instance of
fallibilism. And he seems to have used it not only to counter the
Stoics' argument that there are no alternatives to their theory,
but also to suggest that that theory's reliance on self-evident
perceptual impressions is misplaced, even when viewed as an
epistemological ideal. According to Carneades' theory, the
improvement of which our faculties are capable is not a matter of
approaching the condition of perfect discrimination of self-evident
impressions ever more closely; it consists instead in refining
one's appreciation for the complicated relations between
impressions in virtue of which they add to or detract from each
other's value as evidence, which in some cases may lead us to
reject apparently self-evident, true impressions.



Drawing on his account of probable impressions, Carneades defended two
views about assent. He sometimes argued that the wise person will
always withhold assent, but will be able to act and inquire by
following or using probable impressions in a way that does not amount
to assent, and so does not involve holding opinions about anything
(*Acad.* 2.59, 99, 108). On other occasions, he maintained that
the wise person will assent to what is probable and so form opinions,
but with the proviso that he may be wrong (*Acad.* 2.59, 67,
78, 112). In this way he gave his interlocutors a choice between two
alternatives to Stoic orthodoxy, each of which describes a way of life
without the certainty furnished by cognitive impressions. Either one
lives entirely without opinions, while following probable impressions
without assenting to them or one lives with opinions, but opinions
that are held in a self-consciously tentative spirit and subject to
revision in the light of new evidence.



The view according to which the wise person assents and forms opinions
appealed to those convinced by the Academy's arguments that,
though certainty is unobtainable, well founded probabilities are
within our grasp, among which is this view itself. Someone who thinks
this is likely to see little point in keeping a special kind of
approval, assent, in reserve for a kind of certainty which he thinks
is neither needed nor possible, though he cannot be certain of this
any more than he can be certain of anything else. This view was, it
seems, favored by Philo of Larissa among others (cf. Brittain, 2001),
and it gave rise to a form of probabilism, as a positively endorsed
theory of knowledge, which is one of the New Academy's legacies.
The other view, which favors withholding assent while still relying on
probability, appealed to those who were attracted, as Zeno and
Arcesilaus had been, to the ideal of certain knowledge, for which it
preserves assent while permitting a weaker form of approval. This is
the classical skeptical stance that was the New Academy's other
legacy, which was defended by Clitomachus, and it also influenced the
other main ancient school of skepticism, the Pyrrhonists. It is
noteworthy that the more radical forms of skepticism defended by
Clitomachus and the Pyrhonists were less firmly attached to the
skeptical proposition that nothing can be known than moderate
skeptics, who assented vehemently to it (*Acad.* 2. 148).


## 3. Ethics



Tackling ethics, Carneades proceeded as he had in epistemology and
constructed a framework intended to capture and do justice to the
motives behind ethical theory. His framework classified not only all
the views about the goal or end of life that had been held, but also
all those that could be held (Cicero, *Fin.* 5.16-21 =
L&S 64EG; cf. Algra, 1997). He sets out from the assumption that
practical wisdom, the knowledge we need to conduct our lives
successfully, must have an object. That is, it must be knowledge of
something other than itself. This immediately rules out of contention
views that identify human good with knowledge without having anything
to say about what it might be knowledge of apart from human good (the
threat of circularity had already been noted by Plato,
*Republic* 505bc). He further supposes that this object must be
one towards which human beings have a natural impulse. There were, he
maintained, three possible such objects: pleasure, freedom from pain,
and the natural advantages such as health and strength. The principle
of virtue corresponds to this initial choice: to be virtuous is to act
with a view to obtaining one of them. There are six simple views about
the goal of life, three of which identify the goal with virtue, that
is, acting with a view to obtaining either pleasure, freedom from
pain, or the natural advantages; and three of which identify it with
actually obtaining one of these objects. Three combined views take the
goal to be a combination of virtue and actually obtaining the
corresponding object. There are thus nine views altogether. The Stoic
position, that virtue is the only good, is the third view mentioned,
namely that the goal is acting with a view to obtaining the natural
advantages whether or not one obtains them.



On different occasions, we are informed, Carneades defended the simple
view that the goal is actually to obtain the natural advantages or the
combined view that it is virtue together with pleasure (*Fin.*
2.35; 5.20; *Acad.* 2.132, 139). His aim seems to have been to
challenge the Stoics by showing that the considerations captured by
the framework do not all point to the Stoic view. By defending the
view that the goal is the actual enjoyment of the natural advantages,
Carneades probably intended to suggest that the considerations which
support taking the natural advantages as the object of our first
natural impulse, as the Stoics did, also count in favor of taking them
to be goods and therefore components of the end. The point of arguing
in support of the view that the goal is a combination of virtue and
pleasure, on the other hand, was probably to show that taking pleasure
as the ultimate object of impulse would require a recognizably
virtuous life, a view for which there were Socratic antecedents in
Plato's *Protagoras.* Neither of these positions had the
kind of independent appeal that Carneades' probabilism and his
views about assent did--our sources always describe them as put
forward for the sake of argument--but Carneades' division
of ethical views was extremely influential, and through Cicero it
shaped the modern understanding of Hellenistic ethical theory (cf.
Striker, 1991 sect. 5; Allen, 2014).



Carneades also raised problems for the Stoic attempts to define of the
end of life in terms drawn from the arts or *technai* (cf.
Striker, 1991 sect. 3).


## 4. Other interests



We are well informed about Carneades' contributions to two other
important philosophical debates. The first concerns the cluster of
issues surrounding fate, voluntary action and freedom; the second
regards the nature and number of the gods.


### 4.1 Fate and Voluntary Action



Our principal source for the Hellenistic phase of the the first debate
and Carneades' contributions to it is Cicero's *De
fato*, which has survived only in an incomplete form. (A Latin
text with an English translation and helpful notes is found in
Sharples, 1991; older but still useful is Bayer, 1963 with a German
translation and notes. On the debate as a whole, see Bobzien, 1998).
It is clear from the *De fato* that Carneades took on both the
Stoics and the Epicureans. Cicero's presentation suggests that
he may have defended a consistent position distinct from theirs. If he
did, here as elsewhere we do not need to decide whether he endorsed it
*in propria persona* or put it forward as an alternative to
challenge to the positions on offer. It was at least the latter,
serving to show the Epicureans and the Stoics that there was another,
arguably better, way to tackle the issues, one that avoided the most
troubling and implausible choices to which they had been led in the
construction of their own theories.



The Stoics held that all things come about by fate. Fate they define
as 'the ordered series of causes, when cause joined to cause
brings about each thing, ceaselessly flowing for eternity'
(Cicero *De divinatione* I 125; Gellius *Noctes Atticae*
7.2.1-3 = L&S 55 K). To maintain that all things are fated in this
context is to hold that every event is the effect of antecedent causes
sufficient to bring it about. In other words, the Stoics were
determinists. And they accepted some of the familiar implications of
determinism, e.g, that a sufficiently powerful intellect with a
complete grasp of the state of the world would be able to predict
every future event (*De divinatione* I 127 = LS 55 O). They
also confronted the familiar problems that determinism seems to
present. If human beings are parts of a deterministic universe and
their every action is the pre-determined effect of causes antecedent
to their existence, there is a plausible argument that all our actions
are involuntary, that as it was often put in the ancient debate,
nothing is up to us or in our power. In no case could we have done
other than what we did. And from this it would seem to follow that we
are not responsible for our actions and, with this, that there is no
scope for blame or punishment, which presuppose that we can be held
morally responsible for at least some of what we do. They solved this
problem to their own satisfaction by defending the first properly
articulated
 compatibilist theory,
 according to which voluntary action is compatible with
determinism.



Epicurus and his followers, by contrast, accepted that if all things
are fated, then all our actions are involuntary, from which it follows
that we are responsible for none of them. They preserved the voluntary
and moral responsibility by rejecting fate, notoriously postulating
the swerve, occasional random uncaused atomic motions (*De
fato* 21-2; cf. Lucretius DRN 2.251-93 = LS 20 F).



Like the Stoics, the Epicureans were also occupied with we may call
logical determinism. According to the principle of bivalence, every
proposition P is either true or false. If there is a future tense
proposition predicting every future occurrence before it
happens-it doesn't matter whether it has ever been
expressed-true at all times before the event, it would seem that
the future is fixed or settled. Aristotle tackled this problem in
*De Interpretatione* 9, though it is unclear whether the
parties to the Hellenistic debate were familiar with his contribution.
Though an argument for the pre-determination of the future from
bivalence alone is possible (there may be hints at *De fato*
21, 29), in Cicero's presentation of the issues, the role of the
principle of bivalence is to lend support to causal determinism. The
idea seems to be that the truth of a proposition at a given time
depends on the state of the world at that time and that the facts
about the world that bear on the truth of a future tense prediction
must be about causes then operative sufficient to bring about the
predicted event.



Carneades' most noteworthy contribution to the debate was to
reject the connection, accepted by both schools, between the principle
of bivalence and causal determinism. These, he argued, were separate
issues. To affirm that a suitably formulated statement about the
future that is true cannot become false implies nothing about fate,
but is merely an explanation of the meaning of the words employed
(*De fato* 20; cf. 27-8). The Stoics were not obliged to
embrace determinism by accepting bivalence and were not entitled to
cite bivalence as a ground for their commitment to determinism; the
Epicureans were not under an obligation to repudiate bivalence because
they rejected fate (*De fato* 20; cf. 32-3).



Even though his proposal would have freed the Epicureans to defend the
swerve without the need to reject a fundamental principle of logic,
Carneades was strongly critical of the swerve. The position that he
put forward as an alternative was supposed to show how the Epicureans
could uphold their cause without the swerve (*De fato* 23; cf.
47-8). It raises interpretive problems that reflect both the intrinsic
difficulty of the issues and the imperfect state of our sources. The
cause of the Epicureans to which Carneades promises to lend support is
the rejection of fate, i.e., the view that every event is the effect
of antecedent causes sufficient to bring it about. But the error from
which he would save them is the postulation of uncaused motion, which
is entailed by the swerve. According to Carneades, there is a way in
which it can be truly said that there is motion without cause and a
way in which it is false (*De fato* 24).



He offers an analogy designed to appeal to the Epicureans. In
Epicurean physics atoms move downwards in straight lines unless
disturbed by collisions with other atoms (collisions that are set in
train by atomic swerves). The downward motion of the atoms is without
a cause if we mean action exerted on them from outside, but their
motion is not unqualifiedly uncaused, for it is their nature to move
as they do (*De fato* 25). The voluntary motions of our
mind-our volitions-are like this, not the effect of
external causes (though there will be external occasions, or as we
might say precipitating causes, for them).



His thought seems to be that the mind possesses a certain autonomy.
Explanations of an agent's actions are always available after
the fact. 'The outcome reveals its causes' (*De
fato* 37). Explanations for voluntary action do not terminate, as
they arguably would if the Epicureans were right about the swerve, in
uncaused motions, and we are not, as it might then seem, playthings of
chance. Rather it is the nature of the mind, and the characteristics
of the minds of the agents who act, which are the causes of their
voluntary actions. But it is not because our actions are
predetermined, not because they are fated, that we act as we do.



How effective Carneades' version of autonomous mental causation
was at disarming the determinist intuitions of his
opponents-then and now-is another matter, of course.


### 4.2 Theology



Two accounts of Carneades' *sorites* arguments against
the existence of the gods have come down to us, one in Sextus
Empiricus (*M* 9.182-90), one in Cicero's dialogue,
the *De natura deorum* (3.43-50).



Sorites arguments are fashioned by assembling as premises a sequence
of conditionals the antecedent of each of which after the first is the
consequent of the preceding member of the series. According to each
premise, if a property belongs to an item or items specified in the
antecedent, then it belongs to the item or items specified in the
consequent. The argument using the property *heap* (Greek
*soros*), from which the genus takes its name, is a good
example. If one grain of sand is not a heap, then the result of adding
one more grain is not a heap; if two grains are not a heap, then the
result of adding one more is not a heap. But it is plain that if one
repeats the operation by which these premises are generated often
enough, the result will be a sequence of conditionals the consequent
of whose last member (n grains of sand are not a heap) is clearly
false. Anyone who agrees that it is false, but who has accepted each
of the conditionals in the sequence, is obliged to reject the
antecedent of the first, that one grain of sand is not a heap, which
seems just as plainly true as the consequent of the last premise is
plainly false. Those who would avoid this face the difficult task of
drawing a line somewhere in the sequence by rejecting one of the
premises and explaining why this conditional and not one preceding it
is to be rejected.



Carneades' theological sorites arguments set out from apparently
unobjectionable ideas about divinity and little by little, on the
basis resemblances and implied grounds for bestowing divine status on
the generally acknowledged gods, enlarge the extension of the divine
until a conclusion that will be received as absurd is reached (cf.
Burnyeat, 1982). The first argument in Sextus' account, for
example, proceeds as follows (*M* 9.182): If Zeus is a god,
then Poseidon is a god, but if Poseidon is a god, then Achelous (a
river) is a god; Achelous is a god, then so too is the Nile; if the
Nile, then every river, then every stream. This, it is implied, is
absurd. Therefore Zeus is not a god, and we are invited to draw the
conclusion that there are no gods because if any being were a god,
Zeus would be a god and it has apparently just been shown that he is
not.



In Cicero's account, Carneades' purpose in so arguing is
said to have been 'not to abolish the gods-what could
become a philosopher less-but to convict the Stoics of having
explained nothing clearly about the gods' (*N.D* 44).
Scholars who follow the lead of this remark take Carneades'
intentions to have been narrowly dialectical-to draw unwelcome
consequences from the commitments of his specifically Stoic opponents,
consequences that for all the argument tells us follow only Stoic
assumptions (see Couissin, 1941). But though the Stoics may be
vulnerable to Carneades' sorites arguments, the understanding of
the divine on which the arguments depend is hardly peculiar to them.
In Cicero the arguments are presented by the character Cotta, a priest
in the Roman religion, who speaks the words describing
Carneades' intentions just cited. Cicero's decision to
make Cotta the spokesperson for Academic skepticism in his dialogue
tells us something important about it, that it was possible to combine
Academic skepticism with religious conviction. But the attitude, which
resembles fideism, that Cotta attributes to Carneades may not have
been Carneades'. There is no special reference to the Stoics in
Sextus' presentation. Carneades' arguments, like those in
the broader context, may have been intended to raise doubts about the
existence of the gods that did not depend on Stoic philosophy and had
implications that were not for the Stoics alone. Carneades would have
been arguing not as a committed atheist of course, for he would have
been sensible of the force of the argument in support of the
gods' existence, but perhaps as a pioneering agnostic (see
Sedley, 2020).



Carneades also had a hand in the arguments raising problems in logic
described in Cicero's *Academica* (*Acad.*
2.91-8; cf. Barnes, 1997) and in the case against divination
presented in his *De divinatione*.