Wolfson on the Internal Senses in Medieval Philosophy
Given the muddled analyses with which scholars, both classical and contemporary, have considered Aristotle’s treatment of phantasia, it is not surprising that in the Middle Ages various interpretations were proposed to render Aristotle’s theory of sensation and perception coherent and consistent. Among these early attempts, the Arabian philosophers, especially Avicenna and Averroes, stand out. In the above texts from the Summa Theologiae, Aquinas notes that Avicenna held that the phantasia is a distinct and separate faculty of inner sense. However, in the Summa Theologiae, Aquinas clearly rejects the need for a fifth faculty of internal sense. Aquinas’s mentor, Albertus Magnus, to the contrary, at times claims the existence of five faculties of internal sense, one of which was the phantasia. According to the account ascribed to him in the Libri Tres de Anima,10 Albertus lists five faculties of the internal senses: the common sense, the imagination, the aestimative faculty, the memory, and the phantasia. In his Summa de Homine,11 however, Albertus places the sensus communis with the external senses. He then lists four faculties of internal sense: imagination, aestimative, memory, and phantasia. Accordingly, Aquinas’s philosophical mentor affirmed the existence of the phantasia as an independent and distinct faculty of the internal senses separate from the imagination. In his classic historical analysis, Wolfson indicated four different ways in which Albertus classified the internal sense faculties.   It is interesting to note that in one text, Albertus assigned to the phantasia the ability to ‘combine and divide’ images and intentions. The extended passage discussing the internal sense faculties from the Summa Theologiae considered above indicates that Aquinas attributed to Avicenna the postulation of an additional and distinct internal sense faculty whose function was to ‘combine and divide’ images. Wolfson referred to this internal sense faculty as the ‘compositive imagination’. Wolfson in turn attributed a second function to the imagination, which he called ‘the retentive imagination’. Hence, Avicenna had two internal sense faculties of imagination: the compositive imagination and the retentive imagination. In the Summa Theologiae, however, Aquinas rejected Avicenna’s position. Aquinas ascribed to the imagination as one faculty both the ‘retentive’ and the ‘compositive’ functions that Avicenna and Albertus attributed to distinct and separate faculties. Aquinas argued that there is no need for a separate faculty distinct from the imagination to provide this function of ‘combination and division. Therefore, even though some of Aquinas’s predecessors affirmed that the phantasia is a separate faculty of the inner sense—an interpretation that Weinberg and Stump attributed to Aquinas—in the Summa Theologiae, Aquinas rejected this position. It may be that Aquinas’s combination of these two functions into one faculty is his use of Occam’s razor.15
Parenthetically, it is interesting to note that, although both Avicenna and Albertus postulated the phantasia as a faculty of inner sense distinct from the imagination, each philosopher assigned a different cognitive function to this internal sense faculty. In many texts, Albertus assigned to the phantasia the power to ‘combine and divide’ images—Wolfson’s ‘compositive imagination’. Avicenna, on the other hand, assigned this compositive function to the imagination itself and not to the phantasia. What Wolfson refers to as the ‘retentive imagination’ Avicenna calls the phantasia, while Albertus relates this ‘retentive’ function to what he calls the imagination. Aquinas combined both functions with one faculty: ‘phantasia sive imaginatio, quae idem sunt’. Wolfson also notes that in one work, the Isagoge in Libros de Anima, Albertus identified the phantasia with the sensus communis; in his De Anima, Avicenna made the same identification.16 This discussion indicates that philosophers of the high Middle Ages, in discussing the inherited natural psychology of Aristotle, offered significantly different accounts of the scope, function, and number of faculties of what Aristotle in his De Anima referred to only as the phantasia.17
The difference in analysis of this set of issues considering Aquinas’s use of phantasia in the Summa Theologiae and in his Sentencia Libri De Anima resolves in principle several of the conceptual muddles discussed so far. Insofar as a phantasm is not needed by the sensus communis, this faculty is not part of the phantasia. In his Commentary, Aquinas remarked: ‘it is by the phantasia that we become conscious of phantasms’ (Commentary on the Soul, no. 638). It is possible that this generic use of ‘phantasia’ is due to the fact that, while in his De Anima Aristotle mentioned the imagination, he had no general term by which to refer to those faculties which came to be known later by the medieval philosophers as the internal senses. The Jewish, Arabian, and Latin philosophers of the Middle Ages postulated additional faculties in order to account for the various functions and cognitive abilities of the internal senses as distinct from the five external senses.
-  Albertus Magnus, Libri Tres de Anima, in Omnia Opera, ed. Borgnet, lib. 2, tract. 4, c. 7, vol. V,pp. 302-4; in George Peter Klubertanz, SJ, The Discursive Power: Sources and Doctrine of the Vis CogitativaAccording to St. Thomas Aquinas (St Louis, Mo.: Modern Schoolman, 1952), 135-8.
-  Albertus Magnus, Summa de Homine (pt 2), title of q. 18, vol. 35, pp. 164, 323; in Klubertanz, TheDiscursive Power, 139-42.
-  Harry Austryn Wolfson, ‘The Internal Senses in Latin, Arabic, and Hebrew Philosophic Texts,Harvard Theological Review 28(2) (1935), 116-18. Wolfsons article is a classic historical analysis of thedevelopment of the various positions medieval philosophers held in discussing the function of the internalsenses.
-  Libri Tres de Anima, 303, in Klubertanz, The Discursive Power, 136-7; also Wolfson, ‘The InternalSenses, 117.
-  Ibid., 116-18.