The Argument the Academics press against the Stoics
Cicero (106 - 43 BCE)
"It was these statements of the
Stoics that Arcesilaus controverted by proving that cognition is not a criterion intermediate between
knowledge and opinion"
(Sextus Empiricus, Against the Logicians I.153).
"If, then, impressions are cognitive in so far as they attract us to assent and to the following of them up with corresponding action, then, since false ones also are seen to be of this kind, we must declare that the non-cognitive impressions are indistinguishable from the cognitive" (Sextus Empiricus, Against the Logicians I.405).
"They summon the Stoics to face apparent facts. For in the case of things similar in shape but differing in substance it is impossible to distinguish the apprehensive presentation [or cognitive impression] from the false and non-apprehensive. If, for example, of two eggs that are exactly alike I offer each one in turn to the Stoic for him to distinguish between them, will the Sage be able on inspection to declare indubitably whether the egg exhibited is this one or that other one? And the same argument also holds good in the case of twins" (Sextus Empiricus, Against the Logicians I.408-410).
"Arcesilaus... was the first to suspend his judgement owing to the contradictions of opposing arguments. He was also the first to argue on both sides of a question, and the first to meddle with the system handed down by Plato..." (Diogenes Laertius, Lives of the Philosophers IV.6.28). "It was entirely with Zeno, so we have been told, that Arcesilas [who changed the focus of the Academy] set on foot his battle, not from obstinacy or desire for victory, as it seems to me at all events, but because of the obscurity of the facts that had led Socrates to a confession of ignorance.... Accordingly Arcesilas said that there is nothing that can be known, not even that residuum of knowledge that Socrates had left himself—the truth of this very dictum [that nothing can be known]: so hidden in obscurity did he believe that everything lies, nor is there anything that can be perceived or understood, and for these reasons, he said, no one must make any positive statement or affirmation or give the approval of his assent to any proposition, and a man must always restrain his rashness and hold it back from every slip, as it would be glaring rashness to give assent either to a falsehood or to something not certainly known, and nothing is more disgraceful than for assent and approval to outstrip knowledge and perception. His practice was consistent with this theory—he led most of his hearers to accept it by arguing against the opinions of all men, so that when equally weighty reasons were found on opposite sides on the same subject, it was easier to withhold assent from either side. They call this school the New Academy..." (Academica I.45-46).
"[Philo (head of the Academy after Clitomachus) had] maintained that there was nothing that could be grasped (that is the expression that we choose in rendering ἀκατάληπτον), if that ‘presentation’ [or 'impression'] of which he spoke (for we have by this time sufficiently habituated ourselves by our yesterday’s conversation to this rendering of φαντασίᾳ) was, as Zeno defined it, a presentation impressed and moulded from the object from which it came in a form such as it could not have if it came from an object that was not the one that it actually did come from (we declare that this definition of Zeno’s is absolutely correct, for how can anything be grasped in such a way as to make you absolutely confident that it has been perceived and known, if it has a form that could belong to it even if it were false?)—but when Philo weakens and abolishes this, he abolishes the criterion between the unknowable and the knowable; which leads to the inference that nothing can be grasped..." (Academica II.18).
The Latin percipi in "cannot be perceived (percipi)" is the present passive infinitive of percipio, which is a compound formed from per ("thoroughly") + capio ("capture, seize"). This sense survives in English when someone is said to be "perceptive." Such a person grasps the facts ("sees" what is going on) in situations that often confuse others. "[The] argument [the Academics press against the Stoics] is constructed as follows: 'Some presentations [or impressions] are true, others false; and what is false cannot be perceived [or seized and captured because false impression represent something that is not there to be seized]. But a true presentation is invariably of such a sort that a false presentation also could be of exactly the same sort; and among presentations of such a sort that there is no difference between them, it cannot occur that some are capable of being perceived and others are not. Therefore there is no presentation that is capable of being perceived" (Academica II.40-41).
"[T]he way in which they [the Academics] harp on cases of resemblance between twins or between the seals stamped by signet-rings is childish. For which of us denies that resemblances exist, since they are manifest in ever so many things? But if the fact that many things are like many other things is enough to do away with knowledge, why are you not content with that, especially as we admit it, and why do you prefer to urge a contention utterly excluded by the nature of things.... For it is granted that two twins are alike, and that might have satisfied you; but you want them to be not alike but downright identical, which is absolutely impossible" (Academica II.54-55).
"We may suppose Arcesilaus putting the question to Zeno, what would happen if the wise man was unable to perceive anything and also it was the mark of the wise man not to form an opinion. Zeno no doubt replied that the wise man's reason for abstaining from forming an opinion would be that there was something that could be perceived. What then was this, asked Arcesilaus. A presentation, was doubtless the answer. Then what sort of impression? Hereupon no doubt Zeno defined it as follows, a presentation impressed and sealed and moulded from a real object, in conformity with its reality. There followed the further question, did this hold good even if a true impression was of exactly the same form as a false one? At this I imagine Zeno was sharp enough to see that if a presentation proceeding from a non-existent thing could be of the same form, there was no presentation that could be perceived. Arcesilas agreed that this addition to the definition was correct, for it was impossible to perceive either a false presentation or a true one if a true one had such a character as even a false one might have; but he pressed the points at issue further in order to show that no presentation proceeding from a true object is such that a presentation proceeding from a false one might not also be of the same form. This is the one argument that has held the field down to the present day" (Academica II.77-78).
"If a person looking at Publius Servilius Geminus used to think he saw [his twin] Quintus he was encountering an impression of a sort that could not be perceived, because there was no mark to distinguish a true presentation from a false one; and if that mode of distinguishing were removed, what mark would he have, of such a sort that it could not be false, to help him to recognize Gaius Cotta, who was twice consul with Geminus? You say that so great a degree of resemblance does not exist in the world. You show fight, no doubt, but you have an easy-going opponent; let us grant by all means that it does not exist, but undoubtedly it can appear to exist, and therefore it will cheat the sense, and if a single case of resemblance has done that, it will have made everything doubtful; for when that proper canon of recognition has been removed, even if the man himself who you see is the man he appears to you to be, nevertheless you will not make that judgement, as you it it ought to be made, by means of a mark of such a sort that a false likeness could not have the same character" (Academica II.84).