The human intellect is in potency and moves to act. All that which passes from potency to act necessitates an agent of the same species as the thing that must pass on to the act. The intellect as well, therefore, in order to pass from potency to act, needs an active intellect which is always in act and never in potency. When man’s intellect reaches its extreme perfection, it comes close in its substance to the substance of this active intellect. In its search for perfection, man’s intellect tend