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 BC. The work is largely written in the Doric dialect, but contains small examples of the Attic and Ionian dialects as well. One possible author is the Pyrrhonist philosopher Zeuxis. Diogenes Laërtius reported that Zeuxis was a friend of Aenesidemus and that he wrote a work titled "Dissoi Logoi." "Dissoi Logoi", also called "dialexeis", is a two-fold argument, which considers each side of an argument in hopes of coming to a deeper truth. The dissoi logoi doctrine provides historical insight into early sophistic rhetoric. Silvermintz notes that while "dissoi logoi" purports to offer a consideration of both the absolutist and relativist positions, the latter chapters defending the sophists demonstrate its allegiance to the relativist position. It is similar to a form of debate with oneself and holds that contradiction is an inevitable consequence of discourse. Rhetorician John Poulakos sees dissoi logoi as the ability or practice of providing a contrary argument at any point on any issue. He says that people must be persuaded to one side or the other in order to act, and this is accomplished through dissoi logoi. It considers demonstrating contrasting arguments in a single oration a method of demonstrating skill. Protagoras stated that every argument had two contradicting sides, both of which could be argued. This idea emphasizes the power and versatility of language. A definite parallel can be drawn between the thoughts of Protagoras as recounted by Plato, and the rhetorical methods used in the "Dissoi Logoi". Aristotle supported this idea by stating that it is necessary to think in opposites to anticipate counterarguments and to arrive at the true state of an idea, object, etc. He also states that what is beneficial for one group might not necessarily be advantageous for another. "Dissoi Logoi" considers that rhetoric can be situational. In regards to Gorgias, the persuasive argument is dependent upon what seems logical according to the situation at any given time. Good and bad are relative to context, point of view, time, place, etc. Edward Schiappa further simplified the concept of dissoi logoi by putting the concept into the following form: "X can be Y and not-Y."