Book 1
2.16
As to signs, some are related as the particular to the universal, others as the universal to the particular. Necessary signs are called tekmeria; those which are not necessary have no distinguishing name.
2.17
I call those necessary signs from which a logical syllogism can be constructed, wherefore such a sign is called tekmērion; for when people think that their arguments are irrefutable, they think that they are bringing forward a tekmērion, something as it were proved and concluded; for in the old language tekmar and peras have the same meaning (limit, conclusion).
