Medieval Mereology (review)

132 JOURNAL OF THE HISTORY OF PHILOSOPHY 3~: i JANUARY 1994 on/y true constituent of an entity," every endty is tm//ke the One inasmuch as its very existence is a "diminution of the One" (15). De Rijk concludes that when a lower existent "participates in" a higher one, "what is participated" is not the higher existent as such but the degree of unific power "communicated... to the effect" (16). Next, H. D. Saffrey discusses the interplay of Orphic, Pythagorean, and Platonic themes in the Neoplatonic school at Athens; and Carlos Steel examines Proclus' understanding of Plato's Parmenides and Sophist. Of special note is Steel's contrast between how Plotinus and Proclus understand Plato's five "genera of Being": In Plotinus they conjoindy characterize how/nteU/g/b/e Being proceeds from the One; whereas Proclus maintains the primacy of Being and understands Plato's genera as properties of a metaphysical order deriving from Being as such, distinct even from Intellect (63). P. A. Meijer returns to Proclean participation and argues that Proclus sometimes doesdenote a higher existent as "what is participated in" by a lower entity (67). Proclus' One does not "proceed" merely in successive diminutions of Its power but concurrently produces a special order of separate existents (the Henads) which are similar to (71) or "cognate with" It (73). Indeed, this occurs with every productive "one" (71); and although every "higher" cause as such remains unparticipated, its simulacrum somehow is participated in by the lower existent. Meijer observes the close textual relationship between these participated Henads and the One's "transcendent light" or "unifying force" (77-78), however, which compromises the claim that they are distinct from the causal hierarchy articulated by de Rijk. The remaining essays discuss Proclus' influence on medieval thought. A. de Libera discusses how commentary on the L/bet de caus/.,led to distinctions regarding universals and their relation to Divine Ideas. Jan Aersten examines the influence of the L/bet de causison doctrines of"transcendentals." Werner Beierwaltes emphasizes Proclean Neoplatonism 's influence on medieval theism, paying special attention to Eckhart's theology. Finally, E. P. Bos sees attempts by Scotus, Ockham, and others to understand causality in general as also shaped by Neoplatonism's hierarchic conception of causality. These essays illuminate Neoplatonism's importance to the language and debates of medieval philosophy but they tend to ignore somewhat other sources to those developments. MICHAEL F. WAGNER University of San Diego Desmond Paul Henry. Medieval Mereology. Amsterdam: B. R. Griiner Publishing Co., x991. Pp. xxv + 609. Cloth, NP. This is a wide-ranging and pioneering book. Concerned to give an idea of the range and content of medieval thought on part and whole, it consists in a series of commentaries on medieval texts ranging from the sixth to the fifteenth centuries. Its strengths lie in its presentation of many important and sophisticated medieval accounts of part and whole, together with many penetrating and detailed discussions by the author. Marring the book, however, are a number of sketchy discussions, a degree of repetitiveness and stylistic awkwardness, and some poorly proofread Latin quotations. BOOK REVIEWS ~33 There is a need for a work on this aspect of medieval thought. Medieval thinkers are constantly referring to notions of part and whole, but often in senses quite foreign to the modern reader. Thus besides notions of part and whole in a properly mereological sense, as Henry puts it, that refers to integral wholes and their parts (often taken as quantitative), we find notions of part and whole used in an essential sense, in which a genus or species is taken as a whole in relation to its subordinated species or individuals. The reader will find illuminating discussions of these and other distinctions. The book's best parts are the long discussions of twelfth-century material and Aquinas. Henry carefully examines the sophisticated accounts found in Abelard and related twelfth-century texts. Of particular interest are concerns over the relationship between quantitative change and persistence over time. Henry plausibly sees in Abelard the extreme "destructivist" view that upon the removal of any quantitative part of an object that object no longer exists. This is closely related to...