Plato: Collection and Division

In the first book of the Prior Analytics, Aristotle sets out, for the first time in Greek philosophy, a logical system. It consists of a deductive system (I.4-22), meta-logical results (I.23-26), and a method for finding and giving deductions (I.27-29) that can apply in “any art or science whatsoever” (I.30). After this, Aristotle compares this method with Plato’s method of division, a procedure designed to find essences of natural kinds through systematic classification. This critical comparison in APr I.31 raises an (...) interpretive puzzle: how can Aristotle reasonably juxtapose two methods that differ so much in their aims and approach? What can be gained by doing so? Previous interpreters have failed to show how this comparison is legitimate or what important point Aristotle is making. The goal of this paper is to resolve the puzzle. In resolving this puzzle we not only learn more about the relationship be- tween division and the syllogistic in Aristotle. We will also learn something about the motivation for the syllogistic itself, by seeing the role that it plays in his philosophy of science. (shrink)

The many definitions of sophistry at the beginning of Plato’s Sophist have puzzled scholars just as much as they puzzled the dialogue’s main speakers: the Visitor from Elea and Theaetetus. The aim of this paper is to give an account of that puzzlement. This puzzlement, it is argued, stems not from a logical or epistemological problem, but from the metaphysical problem that, given the multiplicity of accounts, the interlocutors do not know what the sophist essentially is. It transpires that, in (...) order to properly account for this puzzle, one must jettison the traditional view of Plato’s method of division, on which divisions must be exclusive and mark out relations of essential predication. It is then shown on independent grounds that, although Platonic division in the Sophist must express predication relations and be transitive, it need not be dichotomous, exclusive, or express relations of essential predication. Once the requirements of exclusivity and essential predication are dropped, it is possible to make sense of the reasons that the Visitor from Elea and Theaetetus are puzzled. Moreover, with this in hand, it is possible to see Plato making an important methodological point in the dialogue: division on its own without any norms does not necessarily lead to the discovery of essences. (shrink)

The main aim of the French logician and philosopher Petrus Ramus was to provide a method of teaching the liberal arts enabling the completion of the undergraduate program of studies in 7 years. This method was based on a new logic, in which the complex structure of Aristotle’s Organon and of the Summulae logicales of Peter of Spain is reduced to two main doctrines: the invention of arguments, by which it is possible to find the notions for reasoning and disputing (...) in any discipline, and the disposition of arguments in judgment, i.e., in propositions and syllogisms. Since this logic applies both to demonstrative and to probable reasoning, Ramus and Rudolph Agricola, who first introduced it, labeled it as dialectic. Ramus completed this twofold dialectic with a method, according to which disciplines have to be taught by providing general definitions, to be explained by subsequent dichotomous divisions. According to Ramus, this method ensures a well-ordered hierarchy and division of disciplines, and an efficient means to teach them in a shorter time than in the pedagogical programs of Juan Luis Vivès, Johann Sturm, and Philipp Melanchthon. This method had its main diffusion in the pre-university institutions such as the German gymnasia and gymnasia illustria (e.g., of Herborn), while in Reformed and Catholic universities the acceptance of Ramism was hindered by the predominance of the Aristotelian curriculum. (shrink)

Conceptualism—the view that universals are mental entities without an external, independent, or substantial reality—has enjoyed popularity at various points throughout the history of philosophy. While Plato’s Theory of Forms is not a conceptualist theory of universals, we find at Parmenides 132b–c the startling conceptualist suggestion from a young Socrates that each Form might be a noēma, or a mental entity. This suggestion and Parmenides’ cryptic objections to it have been overshadowed by their placement directly after the notoriously difficult Third Man (...) Argument, and before the Likeness Regress. However, in the background of 132b–c, we find illuminating assumptions behind Parmenides’ arguments against the Theory of Forms in the first half of the dialogue. We also find in this text a set of implied criteria for Platonic concepthood. While in the Platonic corpus, Forms are explanantia for many of the phenomena explained by concepts in contemporary philosophy, concepts do seem to have an important epistemic role in Plato’s philosophy. An account of Platonic concepthood therefore opens the door for new ways of understanding the Platonic corpus as a whole. My focus in this paper is to uncover these assumptions and criteria through a close reading of Socrates’ conceptualist suggestion and Parmenides’ truncated objections to it at Parmenides 132b–c. (shrink)

At 252e1 to 253c9 in Plato’s Sophist, the Eleatic Visitor explains why philosophy is a science. Like the art of grammar, philosophical knowledge corresponds to a generic structure of discrete kinds and is acquired by systematic analysis of how these kinds intermingle. In the literature, the Visitor’s science is either understood as an expression of a mature and authentic platonic metaphysics, or as a sophisticated illusion staged to illustrate the seductive lure of sophistic deception. By showing how the Visitor’s account (...) of the science of philosophy is just as comprehensive, phantasmatic and self-concealing as the art of sophistry identified at the dialogue’s outset, this paper argues in favor of the latter view. (shrink)

Aristotle's syllogistic theory, as developed in his Prior Analytics, is often regarded as the birth of logic in Western philosophy. Over the past century, scholars have tried to identify important precursors to this theory. I argue that Platonic division, a method which aims to give accounts of essences of natural kinds by progressively narrowing down from a genus, influenced Aristotle's logical theory in a number of crucial respects. To see exactly how, I analyze the method of division as it was (...) originally conceived by Plato and received by Aristotle. I argue that, while Plato allowed that some divisions fail to rigorously investigate the essence, he began a program continued by Aristotle (and others in antiquity and the middle ages) of seeking norms for division that would apply in any domain whatsoever. This idea of a rigorous, general method was taken up and developed by Aristotle in his syllogistic. Aristotle also used Plato's conception of predication as parthood in his semantics for syllogistic propositions. As part of my argument, I prove that a semantics based on Platonic divisional structures is sound and complete for the deduction system used in the literature to model Aristotle's syllogistic. (shrink)

A close exegesis of the principles of the so-called "god-given method" of dialectic in the Philebus (16bff., 23cff.) and an account of the division of the fifteen kinds of art that "care" for the well-formed city in the Statesman (287bff., 303cff.). I show how this division conforms to and, so, illustrates the "god-given method.".