To explain the alleged philosophical contradiction between the theory of necessity and freedom or free-will in the case of voluntary agents we will clarify the main point of contradiction analyzing briefly two sides of the alleged conflict:
If we limit the principle of causality to the ‘need of effect in its existence for a cause’ and consider the effect as something that depends in its existence on the originator there seems no contradiction between causality and free will. In the first sight it seems possible to have something dependent on something else without any necessary relation between them.
This means that cause would have equal relation to existence and non-existence of its effect and effect would remain contingent and unnecessary. This type of relation between voluntary cause and effect is in accordance with the viewpoint of early theologians and modern usuliyyun. In this way, there would be no contradiction between causality of a voluntary agent and his freedom and free will.
However, as we discussed earlier, causality in the way presented by philosophers cannot be limited to the existential relation between cause and effect. It rather involves necessary relation as well. Existence and necessity of the effect are not separable. Cause cannot bring the effect into existence without necessitating it; otherwise it would lead to groundless preponderance and we know that impossibility of such preponderance is the basis of the principle of causality.
The core of the alleged conflict between causality and free will is the very necessitation of effect by cause. It has been assumed that if the existence of effect is preceded by necessity of existence there would remain no place for free will. In other words, free will or freedom is only possible when the effect has the possibility of both being originated and not originated by the cause. Necessitation of effect is equal to determinism.
There are three elements involved in every voluntary (free) act:
• Willing the act;
• The act itself.
There are two relations between these three: the relation between (a) and (b) and between (b) and (c).
It is usually assumed that after the completion of all factors bearing on the existence of a voluntary act its existence becomes necessary as soon as the agent wills it. Thus, there is a necessary relation between willing the act and act itself.
Not only there is no conflict among this necessary relation between act and will of the agent and free will, but also there can be no free will without this necessary relation. To suppose that there can be will of agent and all requisites without having the act would contradict the free will and power of the agent.
For the same reason, it seems that the dispute between philosophers and modern usuliyyun (and also some early theologians) mostly concerns the first relation, i.e. the relation between prerequisites of willing the act and willing the issuance of act from the voluntary agent and not the relation between act and the will. Modern usuliyyun and some early theologians believe that relation between willing the act in the voluntary agent and its prerequisites is necessary there would be no free will and it would result in absolute determinism.
In any case, the debate between philosophers and their opponents on the necessary relation of cause and effect can be conceived in both aspects of the relation of a voluntary act to its prerequisites, i.e. the relation of the essence of act and will of the agent and the relation of will of the agent and prerequisites of its existence.
Among modern usuliyyun, Mirza Na‘ini (d. 1355 A.H) distinguished four main elements in a voluntary act:
• Prerequisites of will;
• Will (iradah);
• Decision (ikhtiyar);
• Essence of the act.
He meant by ikhtiyar the instant movement of the soul towards the act (the embarking of the soul on the act) and took it as a result of iradah, will.
Mirza Na‘ini takes the first two elements to be involuntary subject to the necessary relation of cause and effect, but he takes the third element, i.e. ikhtiyar that sits in between will and the act to be outside the domain of cause-effect necessity. He takes this to be the key point in voluntariness of act.5
In any case, for Muslim philosophers, especially for Mulla Sadra, the relation of a voluntary act to its prerequisites (iradah or ikhtiyar) and the relation of iradah (will) to its prerequisites is a relation of necessity and the principle of necessary relation of cause and effect is exceptionalness. Mulla Sadra 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”6.
Modern usuliyyun believe that the relation between voluntary act and its prerequisites is by no means a necessary and determined one and that the cause-effect necessity does not include the relation between the voluntary act and its prerequisites. Therefore, even if all prerequisites of a voluntary act were available the act still would not be necessary to be issued by the voluntary agent and it still remains contingent. This contingency or the possibility of acting and not acting or the equal relations of the agent to act and non-act is the core of will and voluntariness in a voluntary agent. Na’ini says:
“If you say: is the fourth idea on which you built al-amr bayn al-amray (the state between two states) and the negation of determinism and made it something between the will and the movement of the muscles contingent or necessary? I would say: No doubt, it is created and contingent, but it is the ikhtiyar itself, an act of the soul and the soul itself bears on its existence, so there is no need for a necessitating cause whose effect is never detached from it, because causality of this type is only there for non-voluntary acts.”7
Some modern usuliyyun have noticed a problem here and tried to solve it. The problem is that if after completion of all prerequisites of a voluntary act including the will itself the act still remains unnecessary it would imply denial of power and will of the agents since the will of the agent would have no role in the emergence of the act and origination of the act falls out of agent’s power. Therefore, if ikhtiyar is taken to mean contingency and unnecessity of existence and non-existence it would imply negation of ikhtiyar.
To respond to this problem usuliyyun have distinguished between two types of necessity:
(a) the necessity prior to ikhtiyar, i.e. the necessity which is source of decision or in other words necessity of cause of ikhtiyar
(b) necessity after ikhtiyar, i.e. the necessity whose source is ikhtiyar or in other words the necessary relation between ikhtiyar itself and its effect: the voluntary act. They maintain that the former is in conflict with ikhtiyar and they deny it, but not only do they accept the latter, but they also take it to be compulsory, because there will be no ikhtiyar without it and there is no conflict between necessity which is caused by ikhtiyar and the ikhtiyar itself.
5. Mirza Na‘ini, Ajawad al-Taqrirat, p. 91.
6. Mulla Sadra, Al-Asfar al-Aqliyyah al-Arbi‘ah, vol. 6, p. 319.
7. Mirza Na‘ini, Ajawad al-Taqrirat, p. 91