Preconditions of Visual Awareness. Object and Medium
With the discussion of the objects and the faculties of sensation completed, the next item is to consider the mental acts of sensation. This will be a twofold analysis: the first part pertains to the mental acts proper to the external sensorium—the external senses and the sensus communis; the second pertains to the mental acts proper to the internal sensorium—the three internal senses of the imagination (vis imaginativa), the vis cogitativa, and the sense memory (vis memorativa). The analysis directly below of the medium in sensation is one of the more difficult aspects ofAquinas’s philosophy of mind.
Sight and Its Object
The following analysis specifically considers the sense of sight. However, all the acts of sensation, which all belong to the category of Sensation-Ia, are the same structurally. A careful reading of the texts in the Commentary reveals Aquinas’s complete structural position on sensation and perception. In these texts, he is more detailed, lucid, and specific about perception than in any other works considered for this study. On the other hand, Kenny comments: ‘The senses are not, for Aquinas, part of the mind. Nonetheless, the best place to begin the consideration of Aquinas’s philosophy of mind is question seventy-eight of the First Part of the Summa Theologiae, in which Aquinas treats of the senses.’1 Pasnau appears to both exult in and raise objections to the philosophical impact of Thomas’s Commentary. In his Thomas Aquinas on Human Nature, he makes much the same argument as Kenny, suggesting that the Commentary on the Soul includes ‘a great deal of material that we would now regard as scientific, and of primary interest to historians of science’ and ‘contains many excursus that by our lights are not philosophical at all’.1   Pasnau mentions several scientific themes discussed by Aquinas. Nonetheless, in the Introduction to his translation of the Commentary, he writes that Aquinas there give his best analysis of several philosophy-of-mind issues.
The argument of this study is that, while disregarding outmoded science is a necessary condition for unravelling the substance of Aquinas’s philosophy of mind, nonetheless Aquinas develops his best account of sensation and perception within this Aristotelian Commentary.
This position on external sensation will be discussed as a three-term necessary relation. This relation serves as the set of necessary conditions for perception. In addition, this relational analysis serves as the basis for a later analysis of that critical yet illusive concept, the phantasm. Furthermore, the externalist and realist thrust of Aquinas’s analysis is prevalent in these discussions on visual awareness. In discussing the connection of Aquinas with recent analytic philosophy, Kerr writes:
Second only to the realism/anti-realism debate in analytic philosophy there is this dispute with the philosophy of mind, dividing those who defend some form of externalism (the mind as situate in the world) and those who advocate some kind of representationalism (minds have no immediate knowledge of the world). Clearly these disputes are interconnected, with the first occupying the traditional ground of metaphysics and the second the field of epistemology.
Far from there being an unbridgeable gap between the philosophical assumptions of Thomism and analytic philosophy, then, the truth is that, under the heading of intentionality— that what our understanding grasps primarily and most readily is the specific nature of material things—one of Thomas’s most distinctive assumptions has been central all along.
Aquinas next begins his detailed analysis of the act of perception with a discussion of the sense of sight. Continuing with the Commentary on the Soul, Aquinas focuses attention on the role of colour:
Aristotle states that [. . .] since the proper sense object is that which each sense perceives of itself exclusively, the sense-object of which the special recipient is sight is the visible. Now in the visible, two things are included; for colour is both a visible and also something else, which can be described in speech, but has no proper name; which visible belongs to things which can be seen by night, such as glow-worms and certain fungi on oak trees and the like, concerning which the course of this treatise will inform us more clearly as we gain a deeper understanding of the visible; however, we have to start from colour which is the more obvious. (Commentary on the Soul, no. 399)
This passage is interesting for several reasons. First, Aquinas suggests that colour is the visible. This becomes the proper object of the sense of sight. This is not, however, an analytic a priori definition. Secondly, he provides evidence for a basic empirical foundation for his discussion of ‘perceiving the visible’. Granting that by sight a person is aware of an object of sensation—which in the case of human persons requires as a necessary condition at least both a colour and a sufficient amount of light—Aquinas also is concerned about those objects which appear to ‘be seen’ in the dark. If this is the case, then there must be at least two categories of the visible: one that is colour, and one different from colour. Aquinas claims that colour can only be perceived under the conditions of sufficient light. Nonetheless, his principal interest is with colour, as this is what he takes to be the proper object of human visual sensation. Like most philosophers, he is interested fundamentally in human sensation and perception and not that of other animals. Furthermore, like most major philosophers in the tradition of the history of Western philosophy, Aquinas pays more attention to the sense of sight than to the other sensibles; however, he considers all five objects of the external senses. Nonetheless, sight plays a special role in his discussion, as this text from his Commentary on the Metaphysics suggests:
Aristotle establishes his thesis by means of an example. Since our senses serve us in two respects: in knowing things and in meeting the needs of life, we love them for themselves inasmuch as they enable us to know and also assist us to live. This is evident from the fact that all persons take the greatest delight in that sense which is most knowing, i.e. the sense of sight, which we value not merely in order to do something, but even when we are not required to act at all. The reason is that this sense—Le. sight—is the most knowing of all our senses and makes us aware of many differences between things.
In this part, Aristotle gives two reasons why sight is superior to the other senses in knowing. The first is that it knows in a more perfect way; and this belongs to it because it is the most spiritual of all the senses. For the more immaterial a power is, the more perfectly it knows. And evidently sight is a more immaterial sense. [. . .] Hence sight is aware of sensible objects in a more certain and perfect way than the other senses.
The other reason that Aristotle gives for the superiority of sight is that it gives us more information about things. This is attributable to the nature of its object, for touch and taste, and likewise smell and hearing, perceive those accidents by which lower bodies are distinguished from higher ones. But sight perceives those accidents that lower bodies have in common with higher ones. For a thing is actually visible by means of light, which is common both to lower and to higher bodies, as is said in Book II of De Anima; hence the celestial bodies are perceptible only by means of sight.
There is also another reason. Sight informs us of many differences between things, for we seem to know sensible things best by means of sight and touch, but especially by means of sight. (Commentary on the Metaphysics, bk I, lec. 1, secs 5-8)
The above passages do not provide arguments but rather indicate that Aquinas judged the faculty of sight to hold a pre-eminent place in the scheme of the external sensorium.
On this issue, he of course follows closely the procedure adopted by Aristotle, who also began his discussion on sensation with sight.
Both Aristotle and Aquinas would fit under the umbrella of Armstrong’s suggestion in Bodily Sensations. Aquinas often writes about the superiority of the sense of sight in comparison with the other faculties of the external sensorium: ‘Now sight, which is without natural immutation either in its organ or in its object, is the most spiritual, the most perfect, and the most universal of the senses’ (Summa Theologiae, I q. 78 a. 3). Nonetheless, there are passages in which the sense of touch appears to be designated as the primary sense faculty. ‘[Touch] is the first and in a way the root and foundation of all senses [. . .] This power is attributed to the sense of touch not as a proper sense, but because it is the foundation of all senses and the closest to the fontal root of all senses, which is the sensus communis’ (Commentary on the Soul, no. 602). This distinction between sight and touch may be made from two different perspectives. Aquinas does state that the sense of sight in seeing is more like the act of the intellect insofar as seeing is an intensely immaterial act of awareness. On the other hand, the physical basis by magnitude for the sense organ in sensing appears to be more related to the sense of touch.
-  Anthony Kenny, Aquinas on Mind (New York: Routledge, 1993), 31.
-  Robert Pasnau, Thomas Aquinas on Human Nature: A Philosophical Study of Summa Theologiae, 1a75-89 (Cambridge: Cambridge University Press, 2002), 12-13.
-  Robert Pasnau (trans.), Thomas Aquinas: A Commentary on Aristotle’s De Anima (New Haven, Conn.:Yale University Press, 1999), p. xiii.
-  Fergus Kerr, OP, ‘Aquinas and Analytic Philosophy: Natural Allies?’, Modern Theology 20(1) (2004),127. Kerr also decries the lack of influence classical Thomism has had on the ‘realism/anti-realism’ and‘externalist/internalist’ debates in contemporary analytic philosophy: ‘While Thomists are (or should be!)realists, the realist/anti-realist debate in analytic philosophy owes nothing to them, even indirectly’(p. 126). Kerr is, sadly, correct in this judgement.
-  Haldane has attempted to remedy this lacuna bemoaned by Kerr by incorporating insights fromAquinas on esse intentionale; Haldane addresses weaknesses in Putnam’s rejection of Brentano’s thesis ofintentionality. See John Haldane, ‘Putnam on Intentionality’, Philosophy and Phenomenological Research52(3) (1992), 671-82.
-  A striking contrast is Alasdair MacIntyre’s Dependent Rational Animals: Why Human Beings Need theVirtues (London: Duckworth, 1999), which seeks epistemological continuities between human awarenessand animal awareness, especially that illustrated by dolphins.
-  Commenting on Aristotle’s approach regarding the faculty of sight, Johansen wrote: ‘Aristotle also mayseem liable to a charge that has been raised against Western philosophers from Plato to Husserl. The chargeis that they base their theories of perception (if not entire philosophies of mind) on the model of vision’:T. K. Johansen, Aristotle on the Sense-Organs (Cambridge: Cambridge University Press, 1998), 21. D. M.Armstrong wrote: ‘When we think of sense-perception, we have a strong impulse to think of sight’: BodilySensations (London: Routledge & Kegan Paul, 1962), 118. An exception to this trend is Edward Lee, ‘TheSense of an Object: Epicurus on Seeing and Hearing’, in P. K. Machamer and R. G. Turnbull (eds), Studiesin Perception: Interrelations in the History of Philosophy and Science (Columbus: Ohio State UniversityPress, 1978), 27-59.