 The most fundamental of John’s philosophical commitments arises expressly from Cicero. Beyond John’s self-conscious (and largely successful) effort to imitate Cicero’s polished style of Latin expression, he embraces the Ciceronian dedication to the program of the New Academy (Nederman 2005; Grellard 2013). The New Academy advocated an anti-dogmatic probabilistic theory of knowledge according to which claims to certainty remain open to challenge, so long as they have not been demonstrated beyond doubt. Cicero distanced himself from the more radically skeptical method of the so-called “Old Academy”, which denied that anything whatsoever could be known with certainty (Cicero De natura deorum: 1.1). As Cicero explains, the New Academy does not foreclose the possibility of the human mind attaining truth (pace the Old Academy), only insisting that the criteria for discerning truth from falsity are not self-evident or intuitive and that the senses can be deceived (Cicero Academica: 2.24.76–2.30.98). Cicero’s skeptical stance has the character not of absolute doubt but of anti-dogmatism.