Internal Senses

Abstract

The internal senses are a class of cognitive faculties that were posited to exist between external sense perception and the intellectual soul. The notion of internal senses was developed in the Arabic philosophy of the Middle Ages on the basis of certain ancient philosophical ideas. The classical list of five internal senses was provided by Avicenna: common sense, retentive imagination, compositive imagination, estimative power, and memory. He also localized these faculties in the three ventricles of the brain. According to Avicenna, the function of common sense is to receive and relate the perceptions of the external senses. The retentive imagination stores the forms of these perceptions, and the compositive imagination processes these forms. Furthermore, estimative power grasps the “intentions” of the perceived objects, such as hostility or pleasantness, which the external senses do not perceive. The intentions are finally stored in memory. Averroes’ position was critical of Avicenna’s view, and both accounts had a remarkable influence in medieval Latin philosophy. Avicenna’s view dominated throughout the Middle Ages, although it was challenged and modified with help of other authorities. Albert the Great adhered to Avicenna in general outline but incorporated some of the views of Averroes, John Damascene, and Qusṭ;a ibn Lūqā. Thomas Aquinas followed the same lines but further modified the view. There were also constantly differing positions concerning whether the brain or the heart is the primary organ of the internal senses. Peter John Olivi and John Duns Scotus presented a novel reading of the estimative function, which gave up the Avicennian notion of intentions as the objects of the estimative faculty. John Buridan reduced the number of internal senses to two: common sense and memory. His view was adopted by some later authors but rejected by others.