Platonism and Naturalism: The Possibility of Philosophy by Lloyd P. Gerson (review)

Lloyd Gerson has a vision of what Platonism is. Those who see things differently may find his vision bewildering. In Platonism and Naturalism, to his credit, his vision is synoptic and impressively focused on critical passages and issues, especially in Plato's metaphysics and epistemology, though ethics also receives much attention. Leaving aside the introduction and chapter 1, chapters 2–6 (38–193) are devoted to Plato and comprise two-thirds of the work. Chapters 7, "Aristotle the Platonist," 8, "Plotinus the Platonist," and 9, "Proclus and Trouble in Paradise," along with brief concluding remarks, comprise the remainder (197–265). Naturally they take up only certain issues in the Platonism of these successors. The introduction and chapter 1 are significant. Beginning from Rorty's "thesis that Platonism and philosophy are more or less identical" (3), Gerson sets out to defend philosophy and thus Platonism from its naturalist opponents, including Quine, Sellars, Davidson, and many others. Anti-Platonists embrace a host of theses, such as antirepresentationalism (it is not possible to represent truth in language or thought), nominalism, materialism, mechanism, skepticism, and relativism. What unites Gerson's naturalists is their denial of a distinct subject matter of "'philosophy' as Plato uses it in Republic and … [their] taking that as equivalent to what Rorty calls 'systematic philosophy' and Aristotle calls 'first philosophy'" (12–13). Attacks on contemporary naturalism recur throughout the chapters. I am not inclined to group philosophers under banners or to rely on isms. Others may be more interested in this aspect of Gerson's book.

The key failing of naturalism is its denial of an intelligible realm, which both is the subject matter of philosophy and allows for explanation of the sensible realm and of itself. While Gerson does not cite a specific feature as responsible for naturalism's failure, it seems that its commitment to nominalism is the culprit. In Gerson's hands, nominalism is read as: there is no sameness without identity. Ultimately it entails that there can be no explanations. Explanation requires universalization. Nominalism can at best provide generalization. Plato's response to naturalism, embodied in Anaxagoras's philosophy as depicted in the Phaedo, is to posit an intelligible realm centered on the Good as it is depicted in the Republic, namely as beyond being and essence and explanatorily responsible, directly and indirectly, for both the intelligible and sensible realms. The Good of the Republic, moreover, is identical with the One specified in the first hypothesis of the Parmenides. This One=Good is distinct from the One as developed in the second hypothesis of that dialogue. There is a difference, according to Gerson, between what he labels the 'Idea of the Good' and the 'Form of the Good.'

Gerson rejects interpretative strategies that rely on the philosophical encapsulation of the individual dialogues, rigid developmentalist or unitarian accounts, the dismissal of Aristotle as an accurate reporter of Plato's doctrines, or the difference between Socrates's and Plato's philosophy as found in the dialogues. Of course, he embraces Aristotle and other, later Platonists as offering valuable insights into Plato's philosophy. From them comes Gerson's perhaps most controversial conclusion concerning Plato: that the Demiurge is the ontological foundation for the array of Forms (85–86). The basis for this identification is the aforementioned distinction of the Absolute One=Good from the subordinate Form of One=Being, which is a unity in multiplicity—think Aristotle's One and the Indefinite Dyad. This Form of Being is the array of Forms, identical with the Timaeus's Living Animal, and the Demiurge is this array. The identification of Forms with the Demiurge anticipates both Aristotle's notion of Nous thinking itself as the actualization of Aristotelian essences, and Plotinus's second hypostasis of Nous. But it also flows from Gerson's account of Forms as neither universal nor particular. Forms, according to Gerson, are universalized in our thinking, or (equivalently) as they function as predicates in our statements...