From Ontology to the Philosophy of Mind
In beginning this analysis, distinctions between epistemology and the philosophy of mind require discussion. Epistemology or theory of knowledge often is seen as rooted in Plato’s Theatetus and developed forward through the canon of Western philosophy; the philosophy of mind or philosophical psychology, on the other hand, is found in philosophical works principally of analytic philosophers following the Second World War. Epistemology traditionally is the study of the nature and conditions of knowledge, especially the justification for knowledge claims and the discussion of means or modes of arriving at true propositions. While seeds of the philosophy-of-mind studies are found in Brentano and Husserl, nonetheless contemporary philosophy of mind is often seen as beginning with the work of Wittgenstein and Ryle. The philosophy of mind, then, is a descriptive and argumentative account of the nature of mental acts, mental states, and processes revolving around the questions of the nature of mind itself. Kenny, like Haldane, once suggested that Aristotle’s De Anima became the medieval textbook for studies in the philosophy of mind and Aristotle’s Posterior Analytics served this role for medieval epistemology. While the distinction is not always clear in medieval texts, nonetheless there are significant differences in the presentation of mind issues that will assist in maintaining this contemporary division of philosophical discussions. In the end, the positions developed by Aquinas rooted in Aristotle’s De Anima will illustrate a version of medieval cognitive psychology conjoined with a version of epistemic naturalism.
In developing the ‘logic’ of Aquinas’s position in the philosophy of mind, one must begin with his account of the fundamental and foundational category in his metaphysics, which is a primary substance. For Aquinas, the philosophy of mind presupposes an ontology of primary substances, which are individuals of a natural kind. Appropriating a realist insight gleaned from Haldane’s writing about Aristotle and Aquinas, this analysis adopts the position that there is ‘no epistemology without ontology’. Furthermore, Haldane argues correctly that one first needs to account for a theory of the person, which person has the dispositional properties—what Aquinas often refers to as ‘powers’—to have cognitions and undertake actions. The theme of a holistic account of the human person as agent and knower is central in Aquinas’s philosophy of mind. Aquinas’s ontology is a world of individuals—a world, nonetheless, of individuals grouped as members of natural kinds. In several significant ways, the twentieth-century discussions of Kripke and the earlier Putnam on natural kind theory are illustrative of several issues that perplexed Aquinas regarding how to categorize the world of individuals. Whatever Aquinas is as a metaphysician, he is neither a Process philosopher nor a Platonist nor a philosopher rooted in the radical empiricism of Locke, Berkeley, Hume, and the early twentieth-century empiricists. Thomas’s metaphilosophy works within the context of both an ontological realism and an epistemological realism, which assumes an ontology of individuals belonging to natural kinds. Accordingly, he argues that it is possible to have both a perceptual and a conceptual awareness of these individuals. At root, this is the ontological foundation stone on which Aquinas constructs his philosophy of mind.
Aquinas’s point, given this metaphysical theory, is how it is possible that these individual primary substances are known. In other words, what kind of intentionality theory must one construct in order to explain how humans are able to be aware of these individuals of a natural kind? In an elementary sense, Aquinas constructs a ‘pipeline’ position on the philosophy of mind, with all the important objects of awareness coming through the various mental acts of the faculties of the external and internal senses leading up to the formation of a species intelligibilis through the ingenious abstractive activity of the intellectus agens and then known as a general concept by the intellectus possibilis. It is the first stages of this pipeline theory—the theory of sensation and perception—that demand the attention of the philosophical narrative in this book. In discussing Aquinas’s theory of mind, Haldane writes that Aquinas ‘makes claims about the nature of the world, the process of cognition, the semantics of natural language, and the character of truth, all of which provide illustrations of both ontological and epistemological realism. 
-  With this ontological thrust, Haldane is in agreement with Chisholm’s analysis of intentionality andin opposition to philosophers rejecting the ontological role for intentionality theory. See John Haldane,‘A Return to Form in the Philosophy of Mind’, in David S. Oderberg (ed.), Form and Matter: Themes inContemporary Metaphysics (Oxford: Blackwell, 1999), 54.
-  This philosophical interpretation depends substantively on Haldane’s work on the role of analyticphilosophy and the development of Aquinas’s theory of intentionality. It may be the case that in considering issues central to a viable contemporary philosophy of mind, Haldane’s category of Analytical Thomism’achieves its best success. Haldane’s analysis suggests a connection once articulated by A. E. Taylor. Writingin the preface to the 7th edn of his classic text Elements of Metaphysics, Professor Taylor wrote about the‘shifting of perspective’ in the study of metaphysics. ‘The fundamental questions, no doubt, remain thesame from one age to another. . . . But the point of view from which the problems are attacked varies withthe age’: ‘Preface to the Seventh Edition, Elements of Metaphysics (London: Methuen, 1924), p. xi. That thisanalytic structure differs from classical Neo-Thomism and strictly historical studies in the philosophy ofAquinas will become apparent as this monograph unfolds.
-  John Haldane, ‘Mind-World Identity and the Anti-Realist Challenge’, in John Haldane and CrispinWright (eds), Reality, Representation and Projection (Oxford: Oxford University Press, 1993), 33.
-  Later in this book, the faculty ofphantasia will be analysed; however, it is useful at the very beginningto indicate which interpretive highway Aquinas followed. The imagination is to the sensus communis as thesense memory is to the vis cogitativa. In animals, the vis aestimativa corresponds to the vis cogitativa inhuman cognitive agents.