A Comparative Consideration of Avicenna’s Argument of the Sincere and Thomas Aquinas’s Argument from Possibility and Necessity for the Creator’s Existence

The “argument of the sincere” (burhān al-ṣiddīqīn) was first introduced by Avicenna as andirect proof for a creator. He tried to provide a nearly ideal and direct version of the proof for God’s existence. The argument from possibility and necessity found its way to the Western philosophy through translations, and then Thomas Aquinas made tremendous efforts to refine and supplement it as a proof for the source of the world.This paper seeks to provide a more clear account of Avicenna’s argument of the sincere in the Islamic world and Aquinas’s argument from possibility and necessity in the Western world as proofs for the creator. It will then be argued that, first of all, these are two different arguments, and despite their shared foundations, they have different structures. It seems that Aquinas’s argument is like the argument from possibility and necessity in Islamic philosophy and theology. Secondly, regardless of how persuasive it might be to the public, Thomas’s argument rests upon controversial philosophical assumptions and involves lengthy premises, whereas Avicenna’s argument has solid rational foundations and structure, achieving its goal through fewer mediating premises.