   The starting point of Avicenna’s logic is that all knowledge is either forming concepts (taṣawwur) by means of definitions—i.e. in good Aristotelian fashion, realizing the genus and specific difference of something—or acknowledging the truth (taṣdīq) of a categorical statement by means of syllogisms. The inspiration here is clearly the beginning of Aristotle’s Posterior Analytics (cf. Lameer 2006). Avicenna took this book seriously, following both the curriculum, in which this book was made the center of logical practice, and especially his two Peripatetic predecessors in Baghdad, Abū-Bishr Mattā and al-Fārābī, who made it the cornerstone of their philosophy and advertised its virtues (cf. Marmura 1990).