All but dismissed by W. D. Ross (Aristotle, 61) as an obsolete exercise in sophistic, Aritotle's Topics has staged a remarkable comeback. Partly because of its importance for Aristotle's thought and partly due to its influence on thinkers from late Antiquity through the Renaissance the Topics remains central to the history of western philosophy, science, and theology. The present work proposes: (1) to provide the necessary [End Page 442] background for a fuller examination of the medieval topical literature and (2) to contribute to a survey of its 'genres' so that a "more comprehensive" view of medieval logic may be attained.
The study has five parts. (1) "The Sources of the Medieval Doctrine of the Topics" introduces Aristotle's Topics and Boethius' De differentiis topicis. (2) "The Medieval Approach to the Sources" examines commentaries on Aristotle and Boethius. (3) "The Doctrine of the Topics in the Middle Ages" surveys commentaries from the tenth through the fifteenth century. (4) "A General Conclusion" summarizes some central ideas of the study. Finally, two appendices contain eighteen previously unprinted texts and list commentaries on the Topics and De differentiis topicis.
The Topics including the Sophistici elenchi are Aristotle's chief works in dialectical as opposed to demonstrative reasoning. Demonstration proceeds from a knowledge of first principles to the conclusions formally deducible from them. Dialectic examines the consequences of propositions on any subject matter apart from knowledge of its first principles. Where the former yields the truths of science the latter issues only in the verisimilitudes of considered opinion. Many other points of comparison must be omitted here. According to Green-Pedersen the main problem of the topical tradition is the nature of the topos or locus of argument which Aristotle does not define. Green-Pedersen traces the history of this concept through various interpretations as axioms (Aristotle), as maxims or relations between terms (Boethius), as confirmations of arguments (twelfth century), as second intentions (thirteenth century) and as "middles" (media) in consequentia (fourteenth century). The best of these discussions is devoted to the concept of locus as second intention in the thirteenth century. The suggestions about the connections between loci and consequentia in the fourteenth century are interesting but debatable. The concept of proof (probatio) which is related essentially to probability (probabilitas) and which contained many topical elements (e.g. the exponibilia) by the end of the fourteenth century deserves treatment within the topical tradition. Finally, Green-Pedersen's verdict that the fourteenth and fifteenth centuries "lacked originality" follows from his methodology. But that methodology is questionable.
The study is limited to the tradition of commentaries on the Topics and the De differentiis topicis. Topical rules in medieval textbooks are noted en passant. Uses of topics in particular disciplines, e.g., rhetoric, mathematics, physics, are excluded. This omission is crucial for the fourteenth century when so-called "probabilistic" reasoning was applied in practically every field from science to theology. The acknowledged connection between Topics 8 and the school exercises called obligationes is left untouched. The decision to omit the Sophistici elenchi (which was part of the Topics in the Middle Ages) leaves the medieval insolubilia literature entirely unrelated to the topical tradition. Fuller attention to how topics actually worked in disputationes would be essential to a balanced understanding of the medieval topical tradition.
The great merit of this book is to have collected in one volume some of the primary sources for the medieval topical tradition. Green-Pedersen's skills in codicology, paleography and philology are considerable and indispensable to gaining access to these materials. As a background for interpretation, however, the focus of the [End Page 443] study on the commentary tradition alone is too narrow. As a survey leading to a "more comprehensive" view o f medieval logic it should not be read without a full complement of other studies now available on medieval logic. [End Page 444]