Sextus Empiricus Pyrrhoniae Hypotyposes 2.11.116

[116] But if the sign serves to reveal the consequent, the consequent is either pre-evident or non-evident. If, then, it is pre-evident, it will not so much as need the thing which is to reveal it but will be apprehended along with it and will not be the object signified thereby, and hence also the thing mentioned will not be a ‟sion” of the object. But if the consequent is non- evident, seeing that there exists an unsettled controversy about things non-evident, as to which of them are true, which false, and in general whether any of them is true, it will be non-evident whether the hypothetical syllogism ends in a true consequent. And this involves the further fact that it is non- evident whether the leading clause in the syllogism is the logical antecedent.