- Aquinas’s Theory of Perception: An Analytic Reconstruction by Anthony J. Lisska
At the beginning of this monograph, Anthony Lisska quotes Dorothea Frede’s observation that “the vis cogitativa is, for Aquinas, ‘an embarrassment’” (4). In the remainder of this very helpful book, Lisska provides a sustained rebuttal to Frede’s statement by arguing that the vis cogitativa is crucial to Aquinas’s overall theory of perception because it “is the faculty by which human perceivers are aware of individuals as individuals of a natural kind” (4). In the course of this argument, Lisska makes an important contribution to our understanding of Aquinas’s philosophy of mind, beginning with a detailed analysis of his understanding of sensation and ending with a description of how phantasms work with the agent and possible intellects. Because the vis cogitativa plays an important role in how we come to perceive objects as individual objects, which can later be abstracted, Lisska carefully walks the reader through each step of the process of sensation, perception, and abstraction, with a special emphasis on Aquinas’s understanding of the inner senses.
In pursuing his analysis, Lisska engages with two sets of conversation partners. First, among contemporary philosophers, he is primarily engaged with other analytical Thomists and at times affirms and at times corrects the work of Robert Pasnau, John Haldane, Eleonore Stump, and Anthony Kenny, among others. Part of his disagreement with some of these contemporary Thomists is methodological, as he argues that Aquinas offers a more robust account of sensation and the inner senses in his commentary on De anima than the more commonly preferred Summa theologiae, which offers an abbreviated account of his philosophy of mind since it is focused on theological issues. In engaging his second set of interlocutors, Lisska demon-strates his concern with the negative impact the British Empiricists (Hume, Locke, Berkeley, et al.) have had upon contemporary philosophies of mind and sees Aquinas’s theories of sensation and cognition as a helpful antidote to the philosophical cul-de-sacs into which their approaches to sensation have led us.
In his first chapter, Lisska raises the fundamental question of the book, which is how Aquinas understands our ability to be aware of individuals as individuals rather than as a bundle of sensations. As Lisska is describing this problem, he also argues for the importance of Aquinas’s metaphysics for understanding his overall philosophy of mind, especially perception, adopting Haldane’s maxim “that there is ‘no epistemology without ontology’” (11). Additionally, Lisska provides his methodological case for the superiority of the commentary on De anima over the Summa theologiae with regard to understanding Aquinas’s theory of perception, arguing that the Summa theologiae focuses on the intellect and will and so does not contain a full account of perception, because the theological commitments of the Summa [End Page 625] limit Aquinas’s need to treat perception (23–27). This is not to say that Lisska ignores the Summa, but rather that he finds the commentary on De anima to provide a fuller account of perception, one that can help us better to interpret the Summa on perception or to fill in blanks that the Summa leaves in Aquinas’s overall theory of perception.
In his next two chapters, Lisska provides his understanding of the metaphysical framework in which Aquinas’s theory of perception operates. In the second chapter, he gives an account of Aquinas’s theory of intentionality, arguing in six propositions that Aquinas is both an ontological and epistemological realist, that “esse intentionale is the cognitive content of an act of awareness” and is dependent upon the ontological status of the knower, and that Aquinas is an externalist in his philosophy of mind (37). Lisska points out that the foundation of Aquinas’s philosophy of mind is his distinction between act and potency, so that our senses and intellects must be properly disposed to receive forms. In the third chapter, Lisska puts Aquinas’s philosophy of...