The Meaning and Foundations of the Principle of Ittifaqi (Coincidence) in Avicenna’s Philosophy

Subsequent to Aristotle, the principle of ‘Ittifaqi (coincidence) is not been permanent nor major', is used by Avicenna in order to solve the problem of induction. The first subject in this study is the question about the meaning and content of this principle from Avicenna’s perspective.        Since the word of “ittifaq” has been used in five meanings, it should be specified which meaning of this word is exactly according to Avicenna' view to elucidate the content of the above principle. Looking thorough works of Avicenna, Sheik-Al-Raees, reveals that “Ittifaq” in the meaning of fortune or any other three meanings (the lack of an agentive cause, the lack of an ultimate cause, and the lack of a causal relationship) has not been his intension but he means it “the presence of an opponent”. Thus, Avicenna argued that a coincidental phenomenon is not considered in relation to its intrinsic cause. A coincidental phenomenon is something that has an intrinsic cause and purpose, and such matters are not general or permanent”. Anything that is evaluated concerning its intrinsic cause is permanent and major. Thus, it should be argued that Avicenna considers permanency and majority as a criterion that indicates a thing acts according to its nature and essence. This study introduces the principle of causality and its requirements (necessity and the congruence of causes and effects), the principle of “a thing will not exist until its existence becomes necessary”, and the principle of “an unnatural phenomenon does not last”.