- The Principle of Non-Contradiction in Plato’s Republic: An Argument for Form by L. Bloom
A book that focuses on the principle of non-contradiction (PNC)1 in Plato is an event in itself. Although many scholars have recognised that the first formulation of this important principle can be found in Plato (Republic 4.436b8-9 and 436e8-437a2; Sophist 230b4-d4; Euthydemus 293c8-9), few of them have ever studied the evidence with the attentive care required for the task. Indeed, the studies devoted to the PNC have concentrated mainly on Aristotle and only rarely have articles (or short sections of books on the history of philosophy) actually addressed the topic in Plato.2 The publication of a book that dedicates almost 300 pages to Plato’s formulation of the PNC is thus remarkable and will be warmly welcomed by ancient philosophy scholars who are particularly interested in metaphysics and epistemology.
As the title of the book explicitly indicates, Bloom’s study concentrates on Plato’s formulation of the PNC in one particular dialogue: the Republic. From the beginning, the author acknowledges that his use of other Platonic dialogues will be limited. Such a methodological choice is favourable, as it allows the author to examine in great depth and with considerable insight the many philosophical problems contained in the Republic (mostly in Republic 4 and 10) and, consequently, to provide a thorough analysis of difficult passages that have been predominantly ignored by most scholars. [End Page 212] Despite the book’s notable merits, it does, however, contain certain drawbacks. In choosing not to venture too much outside of the Republic (with the exception of the Phaedo), the author avoids discussing issues that could have informed the reader of the genesis of the PNC and, thus, on its history. For instance, the link between Republic 4.436b8-9/436e8-437a2 and Sophist 230b4-d4 is not discussed by the author, regardless of the fact that this last passage contains similar terminology to that employed in the Republic and had a clear influence on Aristotle, more precisely on his conception of ‘logical contradiction’ (SE 5.167a23-27). Additionally, the author never discusses other implicit formulations of the PNC found prior to Plato, for example in Parmenides’ Poem (fr. 7) or Gorgias’ On Nature or That Which Is Not, formulations that could have had an influence on Plato’s own formulation of the PNC in the Republic. Moreover, the author barely touches upon the thorny question of the naming of the principle. More precisely, he does not address the important fact that Plato, when talking about what is now called ‘contradiction’, used the plural word enantia (‘contraries’) and not antiphasis (‘contradiction’). This terminological choice must have been important as Plato used the word enantia both in Republic 4.436b9 (where he formulates the PNC) and the Sophist 230b8 (where he describes the elenchus as characterised by ‘logical contradiction’). Lastly, the comparison of the Republic with other Platonic dialogues containing passages related to ‘contradiction’ would have allowed the author to underscore the context in which Plato conceived the PNC, namely a context in which different clans of competing intellectuals, especially the ‘eristics’ or ‘antilogicians’, were disregarding the PNC in order to refute their interlocutors (as described in Plato’s Euthydemus), as well as promote their own brand of philosophia, which was in opposition to Plato’s vision of ‘true’ philosophy. For these reasons (among others), Bloom’s book will be of less interest to scholars who favour a historical or philological approach in the study of philosophy, or to researchers who are looking for a thorough analysis of the history of the PNC in Plato’s entire work.
It should, however, be borne in mind that it was evidently not Bloom’s intention to write a book about the history of the PNC with the Republic as the starting point, nor to discuss terminological issues that are of particular interest to philologists. In fact, the author’s primary concern was to analyse...