Abstract: Gail Fine's On Ideas is a study of Book I of Aristotle's short essay Peri Idēon, in which Aristotle presents a systematic account of a series of five arguments for the existence of Platonic forms along with a series of objections to each of these arguments. Fine's aim in this book is to explore these arguments and the objections that Aristotle makes with a view to determining the extent to which (1) the arguments express premises to which Plato himself is committed and (2) the objections express criticisms to which Plato is vulnerable. The Peri Idēon provides a more precise characterization of the theory of forms than is to be found in any of Plato's dialogues. Nevertheless, Fine takes Plato's middle dialogues to be the target, and so she does not discuss Platonists apart from Plato, nor does she discuss the unwritten dialogues. Fine's study thus examines whether the account of the theory of forms of the Peri Idēon is one that can be fairly ascribed to Plato, and she is also interested in what the Peri Idēon tells us about Aristotle's understanding of Plato. However, the study is not simply historical: the Peri Idēon may well be regarded as the original locus of the debate over the nature of universals, and a major focus of Fine's book concerns such perennial philosophical questions as: ‘Can universals exist uninstantiated?’ and ‘How are universals related to particulars?’. The first chapter consists of the Greek text and Fine's translation of the Peri Idēon; the remainder of the book is an extensive discussion of the five arguments that Aristotle presents for the existence of forms, and of the objections that he makes to these arguments, including the celebrated Third Man argument. Fine points to a dilemma facing the interpreter of the Peri Idēon: either Plato is vulnerable to Aristotle's objections, and the theory of forms must be abandoned as a flawed ontology or Plato is not vulnerable to Aristotle's objections, and therefore Aristotle misinterprets Plato. Fine argues that this dilemma is not exhaustive; rather, if we understand Aristotle's philosophical style and interpretative strategy, we may hold at once that Plato is not vulnerable and yet refrain from accusing Aristotle of misinterpretation. The question of Aristotle's interpretation of Plato, and the extent to which his criticisms in the Peri Idēon are successful, is therefore a very complex issue.

Keywords: Aristotle, Aristotle's criticisms of the theory of forms, Aristotle's understanding of Plato, particulars, Peri Idēon, Plato, Plato's middle dialogues, the theory of forms, Third Man argument, universals