Human Destinies: Philosophical Essays in Memory of Gerald Hanratty

Chapter Twenty: The Unity of Thought in Aristotle, Kant, and Heidegger

t w e n t y the unity of thought in aristotle, Kant, and Heidegger Brian Elliott at the end of the spirited “theological” book (Xii) of his Metaphysics, aristotle cites the words of athena from the Iliad: “a multitude of leaders is not good—let there be one leader!”1 Within its immediate theoretical context the purpose of aristotle’s citation is to underscore his insistence on the necessity of positing a single ultimate cause for all that exists. For aristotle, any division or multiplication of this ultimate cause would imply cosmological imperfection and so compromise the principle of optimal goodness that he presupposes. at first glance, the aristotelian assertion of a single, indivisible originating cause of existence in the form of the “unmoved mover” appears to be of little consequence for the subsequent development of philosophical ontology . yet, given the indissoluble binding of the theological and ontological within aristotle’s thinking, the basic theological posit had profound consequences for his conception of thinking and human understanding, a conception which in one form or another came to dominate Western thought. 491 492 Brian Elliott this essay attempts to throw light on one particular intellectual confluence that exhibits the asserted concern within Western thought to discover a single ultimate principle of ontological or cognitive unity. admittedly, the nature of such an investigation involves broad historical brushstrokes. to draw out the philosophical development in question, the theme of the unity of thought will be examined with reference to two further thinkers in addition to aristotle, namely Kant and Heidegger. the former is chosen in light of his generally acknowledged championing of antimetaphysical thinking. the early Heidegger, despite inaugurating a program of “fundamental ontology,” understands his efforts as a continuation of Kant’s antimetaphysical program , efforts which endeavor to point toward a truly postmetaphysical manner of thinking. What i hope to show through the following discussion is that all three thinkers hold true to the overriding concern for a singular source of unity in thinking. in addition to this basic common concern, however, i wish to adduce evidence of a shift in the conception of this unity from a self-identical and circular thought process (aristotle’s idea of pure nous as purely self-reflective thought) to a movement of imaginative conception. Finally, this shift, which is charted through following key motifs in the thinkers in question, develops in parallel with a gradually consolidated recognition of time as the basis of unity within human understanding and thought. aristotle’s Psychological account of unity in De Anima aristotle’s writings permit two principal ways of elucidating his conception of unity: first, via his analysis of primary substance (ousia) in the central books of the Metaphysics and second, through the theoretical psychology of De Anima. to maintain focus and to provide a plausible linkage to Kant, i shall limit my comments to aristotle’s theory of unity within De Anima.2 Sensibility as the Basic Function of the Human Mind Of all writings within the aristotelian corpus, De Anima comes closest to representing what can be considered a sketch for a general anthro- the unity of thought in aristotle, Kant, and Heidegger 493 pology. not that aristotle considers the soul uniquely human. Following Plato he recognizes a tripartite division of faculties within the soul: the nutritive, sensible, and rational or logical (413a22–b32). Of these it is the logical faculty which is deemed uniquely human (414b16–19). in the first book of De Anima aristotle articulates a key insight which is also to be found within the Metaphysics: “unity and being are said in many ways; the proper sense is being-at-an-end [entelecheia]” (412b8– 9).3 What i translate here somewhat literally as “being-at-an-end” (more usually rendered as “actuality”) constitutes aristotle’s dynamic conception of being proper. With a view to the current task of explicating the unity of thought in aristotle, this conception can be taken as a point of departure: unity is being-in-actuality. But how is this related to aristotle’s account of thinking? aristotle remarks that “the ancients asserted that thinking [phronein ] and perceiving [aisthanesthai] are the same” (427a21–22). though this claim is rejected, aristotle goes to great lengths to demonstrate the profound parallel between these two fundamental capacities of the soul. Here two determinations strike me as most telling. First, perception is said to be a “mean of opposition in...