The Mental Act of the Vis Imaginativa
The next part of this analysis elucidates the function of the internal sense faculty of imagination in Aquinas’s philosophy of mind. There are many passages in which Aquinas discusses the imagination as a distinct faculty of inner sense. Two different terms—imaginatio and vis imaginativa, translated as ‘imagination’ and ‘imaginative power’—are used in discussing the function of the imagination. However, there is no indication that the phantasia belongs in this discussion as a faculty separate from the imagination. Accordingly, it is obvious that Aquinas postulated a special faculty called the imagination, which belongs to the internal sensorium.
The function of the imagination is indicated by the following passage, noted earlier, from the Summa Theologiae: ‘For the reception of sensible forms, the proper sense and the sensus communis are appointed [ . . . ] But for the retention and preservation of these forms, the phantasia or imagination is appointed, being as it were a storehouse [thesaurus] of forms received through the senses’ (Summa Theologiae, I q. 78 a. 4.). This term thesaurus usually is translated as ‘storehouse, which gets to the root meaning of the function of the imagination. In her recent account of inner sense in Thomas, Frede translates thesaurus as ‘treasure house’. The imagination, as a thesaurus, is a faculty whose objects are a complete aggregate of impressions of ‘concrete wholes, which have been sensed previously by the external sense faculties in conjunction with the internal sense faculty of the sensus communis. Accordingly, the imagination has at least the function of storing or retaining the forms of the things directly sensed through the external sensorium. What is conserved, it is important to recognize, takes on the epistemological status of a phantasm. In effect, the imagination is the faculty by which one gains ‘experience’ rather than being a novice. It is by means of the imagination that a person conserves her experience of concrete wholes so that every working of the external senses in conjunction with the sensus communis is not a totally new kind of awareness. This is what the British empiricists usually refer to as ‘the memory, Why Aquinas refers to this faculty as the imagination and not the sense memory must await the discussion on the vis cogitativa and the vis memorativa. The mental acts of the vis cogitativa and the vis memorativa, usually referred to as the ‘sense memory’ in many English translations, are intricately related in much the same manner as the mental acts of the sensus communis are related to the imagination.
This ‘conservation’ or ‘retention’ of ‘concrete wholes’—what Wolfson has referred to as the ‘retentive’ function of the imagination—is, accordingly, not the only mental act of the imagination. Aquinas claims that the imagination is not only a storehouse of the ‘sensible forms’: ‘the imaginative power extends itself to everything which the five senses know, plus it does more’ (Summa Contra Gentiles, bk I, no. 65). This passage suggests that the imagination can retain everything that is known by means of the five external senses in conjunction with the sensus communis, in addition to doing more than is contained within the limits of the external sensorium. In other words, the imagination can be aware of more than what is known directly by means of the external sensorium. What Aquinas points out here is that the imagination has a creative ability—what Wolfson called the ‘compositive’ function of the imagination: ‘There are some powers of knowing which from likenesses first conceived can form others—as in the imagination we can form the image of a golden mountain from those of gold and a mountain’ (Summa Theologiae, I q. 12 a. 6 ad 2). The imagination is, therefore, a wonderfully creative faculty of inner sense in Aquinas’s philosophy of mind. Nonetheless, it is neither identical nor coextensive with ‘introspection’ or ‘private language’ issues, the latter associated with mid-twentieth- century criticisms of Cartesian philosophy of mind. What the imagination stores within its receptive faculty role are the ‘sensible’ forms perceived by the sensus communis. This would be, it appears, the sensible species plus the conditions of the sense faculty and the medium during the mental act of sensation, all three of which are components of an awareness of a ‘concrete whole’ by the sensus communis. The resulting phantasm implanted in the imagination, then, is itself a composite structure that results from the mental act of awareness of the sensus communis.
One must remember that the organ/faculty distinction holds for the internal as well as for the external senses. Often Aquinas, with usual references to the Arabian philosophers, indicates that the internal sense organs are in the brain, rendering the brain itself the physiological basis for the organs of the internal senses. Yet the brain itself, as a material organ, is an instance of esse naturale. All knowing is in the psychological status of esse intentionale. It is the root of intentionality in Aquinas to have an ‘immaterial’ reception of forms serve as the groundwork for all cognitive states. The faculties, however, must be found in a physiological ‘home’, as it were, which is the organ itself; this is what Kenny calls ‘the vehicle’. From Kemp’s history of psychology writings, one learns that the organs of the internal senses are found in the three ventricles of the brain. Esse intentionale, which is a necessary condition for awareness, is not reducible to the physiological events or brain states in the ventricles; Aquinas is not a physicalist. The brain-cell activity in the ventricles would seem to be what Aquinas would call a transient and not an immanent activity. It appears that Kemp is not clear on this distinction between intentional faculty and vehicle organ.
-  The Latin text of the above passage: ‘Opportet ergo quod animal per animam sensitivam non solumrecipiat sensibilium, cum praesentialiter immutatur ab eis set etiam eas retinet et conservat. [... ] Ad harumautem formarum retentionem aut conservationem ordinatur phantasia, sive imaginatio, quasi Thesaurusquidem formatum per sensum acceptarum.’
-  Dorothea Frede, ‘Aquinas on Phantasia’, in D. Perler (ed.), Ancient and Medieval Theories ofIntentionality (Leiden: Brill, 2001), 174. It is unclear what rendering thesaurus as ‘treasure house’ adds tothe understanding of the role of the imagination in the texts of Aquinas. Timothy Suttor renders thesaurusas ‘treasure-store of forms’: ‘Man’, in Thomas Aquinas, Summa Theologiae, vol. 11 (London: Eyre &Spottiswoode; New York: McGraw-Hill, 1968), 139.