Dissoi logoi

Dissoi Logoi (Greek δισσοὶ λόγοι "contrasting arguments") is a rhetorical exercise of unknown authorship, and date. It is intended to help an individual gain a deeper understanding of an issue by forcing them to consider it from the angle of their opponent, which may serve either to strengthen their argument or to help the debaters reach compromise.

In ancient Greece, students of rhetoric would be asked to speak and write for both sides of a controversy. The Dissoi Logoi was found amongst the works of Sextus Empiricus who lived between 160-210 C.E. It was first published by Stephanus in 1570, as an appendix to his edition of Diogenes Laertius, and it is found here divided into five chapters. Thomas Gale first published a version of it with a commentary of its own, in 1671. The first edition with an apparatus criticus was published by Ernst Weber in 1897.

The composition date of the work is unknown. Scholars look to the text to piece out clues as to its origin, but find that even this is ambiguous at best. One possible way to date the work is its mention of the offspring of Polyclitus, a well known Greek sculptor. In the Dissoi Logoi (section 6.8) it states that Polyclitus taught his son (singular) the virtue of ἀρετή. Yet in Protagoras 328c, the usually attentive Plato claims Polyclitus to have in fact two sons, not just one. The Protagoras's dramatic events are conventionally dated to between 429 and 422 B.C.E., so either one of the authors made a mistake in listing the genealogy of Polyclitus, or the Dissoi Logoi was written before Polyclitus had another son, thus dating it to before the 420's B.C.E.

Another interesting reference possibly dating the text is its mention of a victory of Sparta over Athens and her allies at section 1.8. At face value, most tend to accept this as a reference to the Peloponnesian War, and thus claim that the Dissoi Logoi must have been written after this war's terminal date, 404 BC. While this is most probably true, it is by no means sure, because there are other instances of Spartan victory over Athens which add uncertainty to this dating, such as the Battle of Tanagra in 457 BC. Thus the Dissoi Logoi are generally dated to between the 5th and early 4th centuries B.C.E.

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