An art of dialectic will be useful wherever dialectical argument is useful.
Aristotle mentions three such uses; each merits some comment.
1. Gymnastic Dialectic
First, there appears to have been a form of stylized argumentative exchange practiced in the Academy in Aristotle’s time.
The main evidence for this is simply Aristotle’s Topics, especially Book VIII, which makes frequent reference to rule-governed procedures, apparently taking it for granted that the audience will understand them.
In these exchanges, one participant took the role of answerer, the other the role of questioner.
The answerer began by asserting some proposition (a thesis: “position” or “acceptance”).
The questioner then asked questions of the answerer in an attempt to secure concessions from which a contradiction could be deduced: that is, to refute (elenchein) the answerer’s position.
The questioner was limited to questions that could be answered by yes or no; generally, the answerer could only respond with yes or no, though in some cases answeres could object to the form of a question.
Answerers might undertake to answer in accordance with the views of a particular type of person or a particular person (e.g. a famous philosopher), or they might answer according to their own beliefs.
There appear to have been judges or scorekeepers for the process.
Gymnastic dialectical contests were sometimes, as the name suggests, for the sake of exercise in developing argumentative skill, but they may also have been pursued as a part of a process of inquiry.
2. Dialectic That Puts to the Test
Aristotle also mentions an “art of making trial”, or a variety of dialectical argument that “puts to the test” (the Greek word is the adjective peirastikê, in the feminine: such expressions often designate arts or skills, e.g. rhêtorikê, “the art of rhetoric”).
Its function is to examine the claims of those who say they have some knowledge, and it can be practiced by someone who does not possess the knowledge in question.
The examination is a matter of refutation, based on the principle that whoever knows a subject must have consistent beliefs about it: so, if you can show me that my beliefs about something lead to a contradiction, then you have shown that I do not have knowledge about it.
This is strongly reminiscent of Socrates’ style of interrogation, from which it is almost certainly descended. In fact, Aristotle often indicates that dialectical argument is by nature refutative.
3. Dialectic and Philosophy
Dialectical refutation cannot of itself establish any proposition (except perhaps the proposition that some set of propositions is inconsistent).
More to the point, though deducing a contradiction from my beliefs may show that they do not constitute knowledge, failure to deduce a contradiction from them is no proof that they are true.
Not surprisingly, then, Aristotle often insists that “dialectic does not prove anything” and that the dialectical art is not some sort of universal knowledge.
In Topics I.2, however, Aristotle says that the art of dialectic is useful in connection with “the philosophical sciences”.
One reason he gives for this follows closely on the refutative function:
– if we have subjected our opinions (and the opinions of our fellows, and of the wise) to a thorough refutative examination, we will be in a much better position to judge what is most likely true and false.
In fact, we find just such a procedure at the start of many of Aristotle’s treatises:
– an enumeration of the opinions current about the subject together with a compilation of “puzzles” raised by these opinions.
Aristotle has a special term for this kind of review: a diaporia, a “puzzling through”.
He adds a second use that is both more difficult to understand and more intriguing.
The Posterior Analytics argues that if anything can be proved, then not everything that is known is known as a result of proof.
What alternative means is there whereby the first principles of sciences are known?
Aristotle’s own answer as found in Posterior Analytics II.19 is difficult to interpret, and recent philosophers have often found it unsatisfying since (as often construed) it appears to commit Aristotle to a form of apriorism or rationalism both indefensible in itself and not consonant with his own insistence on the indispensability of empirical inquiry in natural science.
Against this background, the following passage in Topics I.2 may have special importance:
It is also useful in connection with the first things concerning each of the sciences. For it is impossible to say anything about the science under consideration on the basis of its own principles, since the principles are first of all, and we must work our way through about these by means of what is generally accepted about each. But this is peculiar, or most proper, to dialectic: for since it is examinative with respect to the principles of all the sciences, it has a way to proceed.
A number of interpreters (beginning with Owen 1961) have built on this passage and others to find dialectic at the heart of Aristotle’s philosophical method.
Further discussion of this issue would take us far beyond the subject of this article (the fullest development is in Irwin 1988; see also Nussbaum 1986 and Bolton 1990; for criticism, Hamlyn 1990, Smith 1997).