They thought of nature as the source of motion.

They thought of nature as the source of motion. Later, in view of the fact that occasionally motions and influences of things occur contrary to their natural propensities, a third kind of action was established called ‘constrained action’ ( fi‘l qasrī ). For example, due to the blowing of the wind, dust may rise toward the sky.

That was related to constrained nature of dust, and it was believed that dust, which is a kind of earth, rises toward the sky by constrained motion, and that it returns to the ground by natural motion. In such cases they believed that the motion would not persist (“ the constrained is not persistent ”).

On the other hand, in view of the fact that it is possible for a willful agent to be forced to move contrary to his own will because of the domination of a more powerful agent, another kind of agent was posited by the name of ‘coercive agent’ ( fā‘il jabrī ), which is to a willful agent as constrained action is to a natural agent.

Islamic philosophers deeply pondered the issue of willful agents and at first divided them into two types: one is the intentional agent ( fā‘il bil-qaṣd ) and the other is the providential agent ( fā‘il bil-‘ināyah ). The basis of this division was observation of the difference between willful agents which sometimes need motivation additional to their own whatnesses, such as man, who must be motivated in order to move of his own will from place to place. This kind is called the intentional agent.

Sometimes a willful agent does not require any motivation, and is called a providential agent. The agency of God, the Exalted, was considered to be of this second kind.

Later, the Illuminationists with greater precision established another kind of agent, the knowledgeable ( ‘ilmī ) and voluntary ( ikhtiyārī ) agent, whose detailed knowledge of his action is the action itself, such as the detailed ( tafṣīlī ) knowledge of a man of his own mental forms is identical with those very forms themselves, and prior to their occurrence the agent has no detailed knowledge of them, but merely has a summary ( ijmālī ) knowledge which is identical with the essence of the agent.

It is not the case that in order to imagine something one needs to imagine previously what one imagines, and this agency ( fā‘iliyyah ) is called agency by agreement ( fā‘iliyyah bil-riḍā ), and they consider divine agency to be of this kind.