This verse, read with the preceding verse, completes the penetrating argument relating to the capacity of ʿaql to perceive. A thought of philosophic significance is skilfully couched in a simile. The eye, as an organ having the capacity to see, nevertheless, cannot do so except with the aid of light. The light illumines the field of the eye’s vision and only then does the act of seeing take place.

Therefore, not only is the existence of light a sine qua non, but also relevant is the quality and intensity of the light. For, poor light or overstrong light will affect the picture received by the eye. It follows then, that a correct and true picture is possible, only when the eye is aided by light of the required nature. Where it is not so, the picture can be blurred, indistinct or obscured.

Similarly, al-ʿaql in man, we have already been told, cannot perceive the truth except with the aid of light from outside, from the proper source, and, such light as will be apt and proper to the capacity and needs of the particular ʿaql (i. e. light of the right quality and intensity).

The seeker of truth has, as his aim, the grasping of the intrinsic truth hidden in a thing as distinct from the form or shape of the thing itself. To enable him to do so, his field of inquiry has, first, necessarily, to be illumined with light—the light from outside which is from a higher luminous stage. One does wonder, as to why and how, man endowed with eyes and ʿaql has yet been restricted, in the sense, that he cannot use the gifts without the aid and companionship of an external element or body. Fatimi philosophy offers a good and acceptable answer. It is a pointer to the very purpose of man’s existence and to the fact that man is made, during his lifetime, irrevocably, to strive towards the goal of the highest perfection. The restriction bridles the animal inclinations and yearnings in man, warns him against giving too much importance to the problems of life here and now and urges him not to forget the more important need of preparing for the life hereafter.