Whether, then, it ought to be pursued or not, practicing dialectic is ⟨worthwhile⟩. For it is absurd to judge everything by reason ⟨yet⟩ abandon the most exact study of reason itself; to surpass the other animals through reason, possessing this distinctive good of human nature, yet exercise it casually and at random; and to be content with reason’s investigation when it is intermingled with things in general, yet reject as worthless reason’s knowledge of itself. In that knowledge, reason turns away from other things and establishes the science of itself as supremely august and precious—as the inscription at Pytho also bears witness.67
In the same letter
II.2.7 · Wachsmuth pp. 20-21
Let us turn, then, to philosophical exercises. First of all are those directed toward recollection: we see these brought to light through skillful questioning, ⟨as⟩ Socrates also demonstrates to Meno. Second would be those employed as midwifery, bringing what has been born into the light and distinguishing which of the offspring are true and which false.68 These too all derive their authority from dialectic, since they are purifications of thought through refutations: they set the interlocutors’ opposing opinions side by side and bring them into collision. Other exercises are offered to hearers for testing and training, or argue about a thesis, or examine the teachings of the ancients. None completes its own task ⟨without⟩ dialectic. In general, one cannot properly give and receive an account unless one has acquired this science of arguments.69
Alas, alas, that facts have no voice for people!If they did, clever speakers would count for nothing.But now, with rhythmic speech, they steal away the plainest truths,so that people do not believe what they ought.71
Euripides in Antiope
II.2.9 · Wachsmuth pp. 22
On any matter one could set up a contestbetween two arguments, if one were skilled in speaking.72
Evenus
II.2.10 · Wachsmuth pp. 22
Many make a habit of contradicting on every matter alike;contradicting rightly, however, is not their habit.For these people a single old saying is enough:“Let those be your opinions, and these mine.”73
Arcesilaus
II.2.11 · Wachsmuth pp. 22
The philosopher Arcesilaus said that dialecticians resemble conjurers with pebbles, who deceive with cleverness.74
Zeno
II.2.12 · Wachsmuth pp. 22
Zeno compared the arts of dialecticians to accurate measures used to measure neither wheat nor anything else of value, but chaff and dung.75
Pythagoras
II.2.13 · Wachsmuth pp. 22
Empty is a philosopher’s discourse that heals no human affliction. For just as medicine is of no use if it does not drive diseases out of bodies, so philosophy is of no use if it does not drive evil out of the soul.76
From Ariston’s Comparisons
II.2.14 · Wachsmuth pp. 22-23
Those who go deep into dialectic resemble people chewing crabs: they busy themselves with many shells for a little nourishment.77
Antisthenes
II.2.15 · Wachsmuth pp. 23
One should put an end to a person’s contradiction by teaching, not by contradicting in return. No one cures a madman by going mad in return.78
Cleanthes
II.2.16 · Wachsmuth pp. 23
Cleanthes was asked why, although few people in earlier times had practiced philosophy, more had nevertheless become distinguished than now. “Because,” he said, “then it was deeds that were practiced, but now it is words.”79
From Serenus’s Recollections · Arcesilaus
II.2.17 · Wachsmuth pp. 23
But avoid dialectic: it turns things upside down.80
Ariston
II.2.18 · Wachsmuth pp. 23
Ariston said that dialectic resembles the mud in the roads: it too is useful for nothing, yet brings down those who walk through it.81
Theocritus
II.2.19 · Wachsmuth pp. 23
To a dialectician who answered him in a strained and contentious manner, Theocritus said:
“Would that strife might perish from among gods and human beings!”82
Carneades
II.2.20 · Wachsmuth pp. 23-24
Carneades said that dialectic resembles an octopus: the octopus eats its tentacles when they have grown, and dialecticians, as their ability develops, overturn their own arguments as well.83
Clitomachus
II.2.21 · Wachsmuth pp. 24
Clitomachus compared dialectic to the moon: it too never ceases to wane and wax.84
Ariston
II.2.22 · Wachsmuth pp. 24
Ariston compared the arguments of dialecticians to spiders’ webs: useful for nothing, but exceedingly skillfully made.85
From Ariston’s Comparisons
II.2.23 · Wachsmuth pp. 24
Hellebore, taken in a coarser form, purges; ground into very fine particles, it chokes. So too with excessive subtlety in philosophy.86
Plato
II.2.24 · Wachsmuth pp. 24
But anyone who would be secure must be especially on guard where resemblances are concerned;87 for this is a most slippery kind of thing.88
The same author
II.2.25 · Wachsmuth pp. 24
But I know that arguments which construct their proofs from probabilities are impostors;89 unless one guards against them, they deceive one thoroughly, both in geometry and in everything else.90