(n. pl.) arguments that both sides think they can win
Arguments that both sides believe they have perfectly sound reasons for winning are known as cacosistata.
Or at least they were in the dictionaries, essays and textbooks of logic that resurrected this term out of relative obscurity in the eighteenth century.
Before then, the term cacosistata was seemingly first brought to English attention in the 1500s by the rhetorician and statesman Thomas Wilson. In his Rule of Reason (1551)—an early English guide to the foreign terms of the rhetoric of antiquity—Wilson explained that:
Cacosistata are such arguments that, being propounded between two persons, they serve as well for the one part as the other, as thus: ‘You must forgive him, because he is but a child; no, marry, therefore will I beat him, because he is a child.’ Or thus: ‘This man should not be judged to die by any temporal law, because he is a priest; yes, marry, therefore should he be judged to die, because he is a priest, and hath offended, which should have given good example to other [people] of well living.
Thomas Wilson, Rule of Reason (1551; text updated here)
From Wilson’s Tudor-period introduction to cacosistata, the term appears to have failed to catch on much in English before being hauled out of obscurity by the lexicographer Nathan Bailey in the early 1700s. Clearly following in Wilson’s footsteps, Bailey defined cacosistata in his Universal Etymological English Dictionary (1721) as, “arguments proposed between two persons, that will serve as well for one as the other.” (He then goes on to include Wilson’s example of the punished child as an example of the term.) From there, later writers maintained the term in their discussions of classical rhetoric, before it drifted into obscurity once more.
We can presume that cacosistata was seen as a fault or vice by the rhetoricians of old by looking at its etymology. The prefix caco– will be familiar to English speakers through words like cacophony and kakistocracy: it comes from the Greek word for ‘bad’, and is used to create words following a similarly negative vein. The Latin verb sistere, meaning ‘to take a stand’, or ‘to stand firm’, appears to make up the remainder of the word (which makes it a none too distant cousin of words like resist, desist, assist and insist).
Cacosistata could thus be described as arguments that clash badly, due to both sides standing firm, refusing to back down from their point of view, and ultimately not furthering the debate or discussion in which they appear.