Immateriality and Intentionality Gerard Casey School of Philosophy University College Dublin gerard.casey@ucd.ie http://www.ucd.ie/philosophy/staff/casey_gerard.htm L’excellence de la Raison ne dépend pas d’un grand mot vuide de sens (l’immatérialite); mais de sa force, de son étendue, ou de sa Clair-voyance. Julien de la Mettrie 1 La théorie de l’intentionnel joue un rôle essentiel dans une métaphysique réaliste. Seule, elle permet une explication cohérente de l’extériorite du monde et de sa connaissance par I’esprit de l’homme. Andre Hayen 2 One cannot go far in the reading of St Thomas Aquinas and other medieval writers without coming across a multiplicity of usages of the Latin term for ‘being’ or ‘to be’, esse, such as esse intentionale, esse intelligibile, esse naturale, esse sensibile and so on. 3 It is not always easy to appreciate the distinctions which these terms are intended to mark and if one is inclined to scepticism one might indeed suspect that these are distinctions without a difference. However, such a judgment would be both precipitate and incorrect. Even if the distinctions marked by such terms are not immediately perspicuous it is essential, if one wishes to understand and appreciate the thought of the medievals, that one come to understand them. Within the compass of a short paper it will not, of course, be possible to be comprehensive, so I shall investigate the notions of immateriality and intentionality with a view to clarifying their relationship. 4 In so doing, I hope some light will be thrown 1 L’Homme machine in Œuvres Philosophiques Volume I (Paris 1987), p. 65. 2 L’lntentionnel selon saint Thomas (Paris, 1954), p. 13. 3 In the passage cited from the Summa Theologiae in footnote 17 below, the terms esse intentionale, esse intelligibile, esse naturale, esse materiale and esse immateriale all occur together in just seven lines of Latin. 4 This paper concerns itself with just a very small part of a large and interesting area of philosophy. In addition to the works cited in the body of the paper, readers interested in this topic may wish to consult some or all of the followings works: Robert W. Schmidt SJ, The Domain of Logic according to Saint Thomas Aquinas (The Hague, 1966); J. Peghaire CSSp, Intellectus et Ratio selon S. Thomas D’Aquin (Paris, 1936); Victor Kal, On Intuition and Discursive Reasoning in Aristotle (Leiden, 1988); Henry Veatch, Intentional Logic (New Haven, 1952); Irving Thalberg, ‘Immateriality’, Mind 92 (1983), 105-13; John N. Deely, ‘The Ontological Status of Intentionality’, The New Scholasticism 46 (1972),220-33; Richard E. Aquila, ‘The Status of Intentional Objects’, The New Scholasticism 45(1971), 427-56; Mark McCarthy, ‘Meaning and Intentional Objects’, Semiotica 23(1978), 165-90; Christian Koch, ‘The Being of Idea: The Relationship of the Physical and the Nonphysical in the Concept of the Formal Sign’, Semiotica 66 (1987), 345-57; John Deely, Introducing