avicenna’s logical innovations and his scientific agenda

I have the hypothesis that avicenna develops his logical theory from the perspective of his metaphysics of quiddity, and that he has the agenda of constructing a theory of scientific demonstration with some novelty.first i summarize avicenna’s threefold distinction of quiddity, where essences have three respects: in themselves, without regard to existence or material conditions; in re, in regards to the individuals actually existing in the world, and in intellectu, in regard to universal concepts abstracted from individuals.i next sketch some perhaps novel logical doctrines of avicenna:• the structure of predication for perceptible individuals; the categorical affirmation, of form ‘s is p’, asserts: that s exists, and that p is predicated of s; the denial: that either s does not exist, or p is not predicated of s. for intelligible individuals; the categorical affirmation asserts: that p is predicated of s.• determination of the time of predication by the content of the terms, as well as by tense and context. this varies by context. for instance: ‘the moon is eclipsed’ is restricted to times of eclipses; ‘the moon has phases’ holds as long as the moon is existent.• a twofold analysis of paronymous terms; e.g., ‘the scribe is sitting’ can be taken to hold as long as the subject is a scribe, or as long as the subject is the substance, a human being.• a defense of aristotle’s claim that a necessary conclusion sometimes follows from a categorical minor and a necessary major premise. this comes from alexander and perhaps aristotle, and uses the doctrine about paronymous terms.• a sharp division of logical and physical modality; the latter makes additional material assumptions tied to what actually exists in the world.• a recognition of three types each for conditional and for disjunctive propositions, with attempts for conversion rules between them;• replacement of the ontological square of categories 2 with a pentagon, a fivefold distinction of beings. avicenna is amending the doctrine from aristotle’s metaphysics and his own theory.i show how these doctrines fit into his metaphysics, of the threefold distinction of quiddity. i propose that avicenna has the agenda of using the theory to develop a new approach to scientific demonstration, similar to hempel’s deductive-nomological explanation today.