Aquinas on Intentionality
Historical and Contemporary Antecedents
Before a detailed analysis of Aquinas’s theory of perception, several general features about his epistemology and philosophy of mind require discussion. The next two chapters provide a concise conceptual elucidation of the principles central to Aquinas’s theory of knowledge and philosophy of mind, together with an explication of what appears to be Aquinas’s rather obscure metaphysical language. This chapter undertakes an analysis of five aspects of intentionality theory and cognitive awareness in Aquinas:
- (a) principles of intentionality in Aquinas’s theory of knowledge;
- (b) how Aquinas differs from contemporary accounts of intentionality theory;
- (c) Aquinas as an empiricist;
- (d) direct realism in Aquinas;
- (e) Aquinas and causal theories of perception.
In his explanatory theory of knowledge and the workings of the mind, Aquinas has four distinct classes of mental acts and their corresponding intentional objects:
- (a) The awareness of sensible qualities like green and square. These are the proper and common sensibles, which are known through the external senses.
- (b) The awareness of distinct individual concreta. Concreta are the particular objects of Aquinas’s ontology—the tulips, oak trees, and sheepdogs of the world, which are individuals of a natural kind. Both Aristotle and Aquinas refer to these concreta as primary substances. For Aquinas, the internal sense of the vis cogitativa accomplishes the awareness of concreta.
- (c) The awareness of essential properties. These are the essential natures or ‘quiddities’ of the primary substances. The act of awareness through the abstractive process of the intellectus agens and the awareness of the intellectus possibilis 1
accomplish the awareness of essential or sortal properties that determine a natural kind. These are first intentions.
(d) The awareness of universals. These are the intentional categories of genus, species, differentia, proprium, and accidens. These logical categories, often called the ‘predicables’, result from the reflective capacity of the intellectus possibilis. These are second intentions. In De Ente et Essentia, Aquinas suggests this distinction between essence and universal.
In developing his philosophy of mind, Aquinas should be read as a philosopher following the advice of the mid-twentieth-century positivist turned metaphysician Gustav Bergmann: ‘epistemology is merely the ontology of the knowing situation.’ This ‘ontological assay, a metaphilosophical principle used by Bergmann, as appropriated by Aquinas, is more elaborate, intricate, and more interesting philosophically than many students of philosophy have been wont to admit. This inquiry provides a lucid analysis of what Bergmann would have called ‘Aquinas’s ontological assay of the awareness situation, with special emphasis on sensation and perception. Kenny wrote, Aquinas’s doctrine of the intentional existence of forms remains one the most interesting contributions ever made to the philosophical problem of the nature of thought.’ In another context, he wrote: ‘[Aquinas’s] map of the mind is a complicated one but it is superior to that offered by many another philosopher.’ Haldane addresses the roots of intentionality found in the texts of Thomas: ‘[G]iven the present day interest in the “aboutness” of thought, it is worth nothing that [...] Aquinas [offers] a turn upon the nature of intentionality and its difference from physical relations. (Indeed, the very term and concept originate in the medieval notion of esse intentionale, the ‘intentional being’ of thoughts.)’
Nonetheless, in ‘Brentano’s Problem,’ Haldane suggests correctly that there are two senses of ‘Aboutness, which need to be distinguished when considering the intentionality theory of Aquinas. ‘Aboutness-1’ refers to the content of any given mental act, either of perception or understanding. ‘Aboutness-2’ refers to the real relation that holds between a mental act and the external world. Haldane argues that Aquinas appropriates this first sense of ‘Aboutness’. The second sense too easily deflates into a real relation requiring objects for nonexistents—a problem with which Brentano wrestled much of his philosophical life. This distinction will be expanded upon as this narrative develops.
-  In this discussion, the terms ‘principles’ or ‘presuppositions’ are used rather than ‘axioms’. A principleor presupposition is not epistemologically a priori or self-evident in its own right and is not epistemologically axiomatic but rather serves an explanatory role.
-  A first intention is the awareness of a thing; a second intention is an awareness of a thought. It followsthat in Aquinas there is a difference between an awareness of an essence and the awareness of a universal.This distinction will be explained in more detail in a later chapter.
-  Gustav Bergmann, ‘Ontological Alternatives’, in Logic and Reality (Madison: University of Wisconsin Press, 1964), 126.
-  While this study focuses attention on Aquinas’s position, nonetheless Richard Taylor reminds us thatthe sophisticated treatments of mind issues found in Avicenna and Averroes should not be overlooked. See‘Abstraction in al-Farabi, in Intelligence and the Philosophy of Mind: Proceedings of the American CatholicPhilosophical Association 80 (2006), 151-68; Richard Taylor and Max Herrera, ‘Aquinas’s NaturalizedEpistemology’ in Social Justice: Its Theory and Practice: Proceedings of the American Catholic PhilosophicalAssociation 79 (2005), 85-102.
-  Anthony Kenny, Aquinas (Oxford: Oxford University Press, 1980), 80.
-  Anthony Kenny, ‘Aquinas Medalist’s Address’, in Intelligence and the Philosophy of Mind, 23-726.
-  John Haldane, ‘History: Medieval and Renaissance Philosophy of Mind, in Samuel Guttenplan (ed.),A Companion to the Philosophy of Mind (Oxford: Blackwell, 1994), 335.
-  John Haldane, ‘Brentano’s Problem’, Grazer Philosophische Studien 35 (1989), 1-32. This essay is anextended analysis of the differing issues that Haldane discerns in the various versions of intentionalitytheory brought forward by Brentano.