Objects and Faculties Teleology in Sensation

This chapter begins the structural analysis of Aquinas’s theory of sensation and perception. It is divided into two sections: the first concerns the objects of sensation and perception, and the second concerns the faculties of sensation and perception. The previous chapter discussed Aquinas’s account of epistemological dispositions, and the following chapter will consider the mental acts of sensation and perception. In his analysis of sense knowledge, all four categories—dispositions, faculties, acts, and objects—are necessary conditions for awareness.

The Priority of Object

The reason for this division between objects of sensation and faculties of sensation is teleological in character: ‘Beginning then, he [Aristotle] observes that before we can decide what the senses themselves are, we must discuss the objects of each sense. For objects are prior to faculties’ (Commentary on the Soul, no. 383); ‘The very essence and definition of each sense consists in its being naturally fitted to be affected by some special object proper to itself. The nature of each faculty consists in its relation to its proper object’ (no. 387). A contemporary philosopher might reasonably remark that this is nothing more than an archaic bit of teleology. This teleology, however, can be understood in two senses, neither of which is overly disturbing philosophically. In the first sense, this teleology is an instantiation of Aquinas’s principle that potencies are related to acts. The knowing faculty is considered ontologically as a potency or a power. Therefore, it is in some way related to its corresponding act: Aquinas affirms consistently that a knowledge potency is what it is only because of its corresponding act. Secondly, Aquinas exhibits a benign sense of teleology. He claims that each sense faculty has a particular object. Hence, different sense faculties do not have a crossreference to different categories of sense obj ects. The faculty of sight is that sense power by which perceivers are aware of colours. The faculty of hearing is that sense power by which perceivers are aware of sounds and so forth. It is impossible for the eye to be aware of the note B-flat. Equally, it is impossible for the ear to be aware of any shade of red. In this instance, this teleological structure is nothing more than a philosophical way of analysing a pre-philosophical datum of experience.

Aquinas opts for what Chisholm called a ‘particularist’ approach in the metaphilosophical issues of epistemology and the philosophy of mind. Chisholm distinguishes between what he calls a ‘methodist’ and a ‘particularist’; both are different metaphilosophical approaches to issues in epistemology theory. Chisholm claims that in criteria for knowledge, two questions can be formulated:

• (a) What do we know? In other words, what is the extent of our knowledge?
• (b) How do we decide whether we know that we know? In other words, what are the criteria of knowledge?

Aquinas, like Reid, Moore, and several ordinary-language philosophers, would be a ‘particularist’.¹ Aquinas establishes entities necessary to explicate his ontology, and only then proceeds to build an epistemology and a theory of mind necessary to account for an intentional awareness of those entities. Put differently, Aquinas, like Chisholm, is concerned with the objects of knowledge. Using Chisholm’s positions, a ‘methodist’ is concerned with establishing a method by means of which a knower establishes a criterion by which to distinguish different pieces of knowledge. Many British empiricists are, Chisholm suggests, adopting the criterial practices of methodism. Aquinas begins by acknowledging the primacy of primary substances in his ontology, and then proceeds to explain how a knowledge of these particular objects is possible.