Active intellect

The agent intellect is a key since the reception of Aristotle in the Middle Ages concept in the epistemology of scholasticism. It is thus called the " active reason " that one opposes the merely "possible reason" ( possible intellect ) or the " passive reason" ( intellectus passivus ). In substance, this distinction is common already in Ancient Greece, where the passive intellect nous dynamei or nous is called pathetikos. Above all, Aristotle addressed the problems related in his book On the Soul ( Book III, Chapter 4 and 5).

The background of the distinction is the doctrine of act and potency. Thus, for Aquinas the possible intellect mere assets, whereby the intellect is fundamentally based on everything while with him the aspect of the activity is in the concept of agent intellect expressed by the to recognize the assets in the act is converted. This activity takes place in the act of human abstraction. The senses provide the first image of the object ( phantasm ), which is already the "ingredients" of the inner sense - common sense, memory, ability to shape detection (vis cogitative ) - contains. The abstraction of " quiddity " ( quidditas ) from the phantasm now takes place in two steps. First, the common sense ( sensus communis) a " perceptual image " ( species sensibilis ) is abstracted, is then taken out of the by the agent intellect in a deepening act of abstraction the "essence" of the object ( the intelligible species ).