A- To distinguish between necessity and determinism and between contingency and free will. According to Sadra, critics of the theory of necessity have failed to distinguish between ikhtiyar and contingency or between determinism and necessity and therefore they have thought that necessary relation of cause and effect would lead to determinism, so to deny determinism which is against our conscience and rational arguments, one has to deny the theory of necessity. However, necessity does not imply determinism and has no conflict with ikhtiyar, just as contingency does not mean ikhtiyar and is not implied by voluntariness of the act.
Necessity and contingency are two mental concepts that are abstracted by mind from the relation between the thing and existence, while determinism and free will are two real qualities attributed to the act outside mind.
Acts of a voluntary agent are characterized as necessary whether or not they are voluntary; because if the voluntary agent is a self-necessary existent his acts also are necessary and if he is self-contingent he and his acts are necessary by the other. Therefore, voluntariness does not imply contingency, just as necessity does not imply determinism.
B- The reality of free will and freedom consists in choosing out of consent and not under an external force imposing an unpleasant choice. Accordingly, every act arising from agent’s consent that is not chosen because of an imposing external factor is a free and voluntary act. Therefore, the main criterion for voluntariness is not contingency; rather it is the consent of the agent and lack of an imposing external factor. Mulla Sadra says:
“When the source of originating something is knowledge and will of the agent, whether knowledge and will are the same or different and whether knowledge and will are the same as the essence of the agent in the case of God or different in other cases, the agent is voluntary and the act is issued from the agent because of his will, knowledge and consent. Such agent is not called by the public or by the elite "involuntary agent". Neither its act is said to be issued out of determinism, though it is necessarily issued from the agent out of his will and knowledge”.8
The criterion for qualifying a voluntary agent as a free agent is that whenever he wills he acts and whenever he does not will he does not act. According to this definition, it makes no difference whether the agent necessarily or unnecessarily wills, because truth of a conditional proposition is compatible with the necessity of the condition or the conditioned.
Therefore, although will of the agent is subject to the principle of necessary relation of cause and effect and its realization or non-realization is necessary, the agent is still voluntary and enjoys complete freedom.
Mulla Sadra rejects the theologians’ definition of the free agent as the one who may act or not. This definition implies the possibility of voluntary act. He says:
“There are two well-known definitions for power, al-qudrah: First, possibility of act and its opposite, i.e. non-act, and second a state for the agent in which he acts if he wills and does not act if he does not will. The first interpretation belongs to theologians and the second to philosophers.”9
He also says:
“The criterion for willingness is to have the will as the cause for the act or non-act. And surely a willing agent is the one that if he wills he acts and if he does not feel he does not act, even if the will [itself] is necessitated by itself or by the other or is impossible by itself or by the other.”10
C- A voluntary act is the one whose existence derives from the free-will of the agent, but free-will itself is voluntary in essence, that is by definition. Voluntariness of free will is not separable from it, though the free will may be caused by causes, which are the origins of the necessity of its existence. In other words, the fact that ikhtiyar itself is governed by the principle of necessary relation of cause and effect and its existence is necessitated by its cause does not turn it into non-ikhtiyar… Ikhtiyar is ikhtiyar by definition, whatever its cause might be and however it is issued from its cause.
On the basis of the above three points, there is no conflict between free will and the principle of necessity. Although the act of the voluntary agent is subject to the principle of necessity and the will of the agent becomes necessary after the completion of perquisites, the act of the voluntary agent is free because it derives from his will.
8. Mulla Sadra, Al-Asfar al-Aqliyyah al-Arbi‘ah, vol. 6, p. 332
9. Mulla Sadra, Al-Asfar al-Aqliyyah al-Arbi‘ah, vol. 6, p. 307.
10. Mulla Sadra, Al-Asfar al-Aqliyyah al-Arbi‘ah, vol. 6, p. 319.