"Aristotle speaks of four kinds of intellect in his book On the soul. These are potential intellect, active intellect, acquired intellect and agentive intellect.
"Potential intellect is a soul, or part of the soul, or one of the soul’s faculties, or a certain something essentially disposed for abstracting the quiddities of all existing things, and their forms without their matter. For some things it makes more than one form, but for all things it makes at least one. Only when this certain something assumes the forms which reside in materials do those forms become abstracted from their materials. When this happens, the forms are called 'intelligibles,' after the abstracting faculty [of the intellect] which assumes the forms of existing things.
"This certain something resembles the matter in which forms are actualized, with one big difference. Imagine some corporeal matter like wax with an impression stamped into it, such that the impression and its form are received in its surface and its depth, and the matter is wholly taken over by that form to the point that in its totality and as a whole the matter is permeated by that form and in fact becomes that form. If you imagine that, you are close to understanding how the forms of things are actualized in that certain something, which behaves like the matter and substrate of a form but differs from all other corporeal matters in that these receive forms in their surface only, and not their depths. In its essence this certain something is identical to the forms of the intelligibles, to the extent that it becomes them, even though the forms and the certain something retain their own dedicated quiddities. For this, imagine a stamp which imparts a cubical or spherical character to wax as it plunges into it, permeates it and takes over its entire length, breadth and depth such that the wax becomes that very character, and what the one is cannot be separated from what the other is. By this analogy, you should understand how the forms of existing things are realized in that certain something which Aristotle calls 'potential intellect' in his book On the soul."
From the Treatise on the Intellect
"Potential intellect is a soul, or part of the soul, or one of the soul’s faculties, or a certain something essentially disposed for abstracting the quiddities of all existing things, and their forms without their matter. For some things it makes more than one form, but for all things it makes at least one. Only when this certain something assumes the forms which reside in materials do those forms become abstracted from their materials. When this happens, the forms are called 'intelligibles,' after the abstracting faculty [of the intellect] which assumes the forms of existing things.
"This certain something resembles the matter in which forms are actualized, with one big difference. Imagine some corporeal matter like wax with an impression stamped into it, such that the impression and its form are received in its surface and its depth, and the matter is wholly taken over by that form to the point that in its totality and as a whole the matter is permeated by that form and in fact becomes that form. If you imagine that, you are close to understanding how the forms of things are actualized in that certain something, which behaves like the matter and substrate of a form but differs from all other corporeal matters in that these receive forms in their surface only, and not their depths. In its essence this certain something is identical to the forms of the intelligibles, to the extent that it becomes them, even though the forms and the certain something retain their own dedicated quiddities. For this, imagine a stamp which imparts a cubical or spherical character to wax as it plunges into it, permeates it and takes over its entire length, breadth and depth such that the wax becomes that very character, and what the one is cannot be separated from what the other is. By this analogy, you should understand how the forms of existing things are realized in that certain something which Aristotle calls 'potential intellect' in his book On the soul."
From the Treatise on the Intellect
