There are two types of objections raised against the proof of the Truthful (the so-called sediqqin borhan i.e. argument provided by true and sincere believers for the existence of God); some being related to the very name of this proof and to whether it fulfills the conditions required by argument by the properly truthful. Other objections, however, subjects the argument to criticism by calling its very construction into question. While Mulla Sadra sees the proof not without objection from the former point of view, he regards its internal construction to be cogent and defensible, attempting an answer to one of the most important objections leveled against it. The objection is that Avicenna’s proof is to demonstrate the existence of the Necessary Being from possibility which is posteriori argument, namely from effect to cause and so it is not so invalid. Returning the so-called posteriori argument to a priori or propterquid argument, Mulla Sadra attempted not only to defend the demonstration of Avicenna as an argument from cause to effect but also remove similar objections posed against the argument from temporal creation or from motion.
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