اعلم أن البرهان قياس مؤلف من اليقينيات بديهية كانت أو نظرية منتهية إليها
Know that demonstration is a syllogism composed of certain premises, whether self-evident or inferential premises ultimately grounded in self-evident ones.
Syllogism specifies a valid inferential arrangement; certain premises distinguish demonstration from dialectic or rhetoric, whose premises have different epistemic statuses.
An inferred premise may also be used demonstratively if its certainty was already established through sound reasoning reaching an appropriate foundation. Mere complexity or popularity does not turn a proposition into certain knowledge.