“…A usual mistake is to interpret ancient logics based on standard logic (for arguments in this sense for Stoic logic, see, e.g., Bobzien, 1996, p. 134;or López-Astorga, 2016c, p. 22) and maybe those logics require to be understood in their contexts. Thus, in the particular case of Boethius' inference, it can be thought, as held by McCall (1966), that Boethius did not accept Philo's interpretation of the conditional, but that he assumed Chrysippus' criterion of it, which is to be found in many texts written by both ancient and contemporary authors (e.g., Cicero, De Fato 12; Diogenes Laërtius, Vitae Philosophorum 7, 73; Sextus Empiricus, Pyrrhoniae Hypotyposes 2, 111; Barnes, Bobzien, & Mignucci, 2008, p. 107;Gould, 1970, p. 76;López-Astorga, 2015b, p. 9, 2016dMueller, 1978, p. 20;O'Toole & Jennings, 2004, p. 479). Based on them, it can be stated that, following Chrysippus of Soli, a conditional is only correct when the denial of its then-clause is in contradiction with its if-clause.…”