and the body facing it.

Their production is also subject to an impediment: the barriers that intervene between the sun and whatever receives its rays.

Likewise, the light emanating from a lamp or other fires arises only through the fire, a body upon which its rays can be reflected, and the absence of barriers between them.

The same applies to the heating caused by fire, the cooling caused by water, the satisfaction of hunger and thirst through bread and water, and all other effects produced by foods, medicines, and other things. Fire requires a body receptive to its effect; rubies, salamanders, and the like are not burned by fire. Likewise, food is beneficial only when the body possesses a capacity receptive to its effect. Examples of this are numerous.

The same applies to an agent acting by choice, such as a human being. His voluntary movement occurs only through a power in his limbs upon which he depends. Yet he is not the maker of his limbs or their powers. Thus, his action depends upon causes beyond his power, and obstacles may arise within his body that prevent him from moving.

This concerns his actions within himself. As for effects external to him, which are said to be generated by his action, some maintain that he does not produce them in any respect; rather, they are produced by Allah Most High. This is the position of many theologians who affirm divine decree.

Others maintain that he does indeed produce them through the generation of effects, as some of the Muʿtazilah hold. It is also related that some of them said that these effects have no agent whatsoever.

In reality, these effects are jointly produced by the human being and the separate cause