270 ///-10 to ///-11
presentation, I believe. So what kind of presentation? Then Zeno defined
it as a presentation which came from an existing thing and which was
formed, shaped and moulded exactly as that thing was. Next question:
could a true presentation be of the same quality as a false one? Here
Zeno was quite sharp and saw that no presentation could be perceived
if, though it came from something which exists, it could be of the same
quality as that which came something which does not exist. Arcesilaus
agrees that the addition to the definition was correct, since what is false
cannot be perceived and neither can what is true if it is just like what is
false. The burden of his argument in those debates was to show that
there in fact existed no presentation coming from something true which
was not such that one of the same quality could have come from some-
thing false.
- This is the one dispute which has persisted [unchanged] until our
own day. For the claim that the wise man would assent to nothing was
not in the least essential to this debate. For he could well perceive nothing
and yet still hold an opinion-which is the view of which Carneades is
said to have approved. However, I follow Clitomachus, rather than Philo
or Metrodorus, and so think that this thesis was advanced as a debating
point rather than as something of which he really approved. But never
mind that now. If opinion and perception are eliminated, suspension of
all assent certainly follows; consequently, if I show that nothing can be
perceived you should concede that [the wise man] will never assent.
Cicero Academica 2.95-98 [III-11]
95 .... But I [a sceptic speaks] leave this point and ask the following
question: if those propositions [i.e., the Liar paradox, etc.] cannot be
explicated and there is no criterion for them such that you could answer
that they are true or false, what is left of your [i.e., the Stoic] definition,
which claims that a proposition is that which is true or false? For if one
takes a group of propositions, I make the further claim that of these
some are to be approved of and some rejected-i.e., the ones which are
contradictory to the former. 96. So what do you make of how this
argument works? 'If you say that it is now light and you speak the truth,
then it is light; but you say that it is now light and you speak the truth;
therefore it is light." Surely you approve of the general form of argument
and say that it is a completely valid argument; that is why you treat it
as the first argument form in your teaching of logic. So, either you will
approve of every argument which uses the same form, or the entire craft
[of logic] is nullified. So see whether you are going to approve of this