Jean Buridan's Logic. The Treatise on Supposition. The Treatise on Consequences (review)

662 JOURNAL OF THE HISTORY OF PHILOSOPHY 26:4 OCTOBER a988 addressed to present-day Muslims who wish to revive Islam; namely, to follow in the footsteps of the early rationalist theologians, the MuCtazilites, and "work to develop a system of Islamic law which would openly make use ofjudgements of equity and public interest, and a system of ethical theology which would encourage judgements of right and wrong by the human mind, without having to look to scripture at every step" (276). These pertinent remarks on themes which are at the center of ethical and political discussions in Muslim circles, coupled with the meticulous and systematic way in which the author has applied the analytical method to classical Islamic themes, render this collection of essays particularly valuable as a contribution to the study of Islamic ethics, as well as the ongoing debate between fundamentalist and reformist thinkers throughout the Muslim world. Furthermore, constant references to and parallels with Greek philosophers, especially Aristotle, highlight the universal relevance of the questions discussed in this book, not only to students of Islam, but to students of comparative theories of value and ethical philosophers as well. MAJID FAKHRY American University of Beirut Jean Buridan's Logic. The Treatise on Supposition. The Treatise on Consequences. Translated, with a Philosophical Introduction by Peter King. Synthese Historical Library, Vol. e7. Dordrecht: D. Reidel Publishing Co., 1985. Pp. xiii + 38o. $59.oo. The two treatises of the influential fourteenth-century nominalist Jean Buridan translated here by Peter King are central to both logic as an art and to logical theory as a branch of philosophy. The Latin texts on which the translation is primarily based are: M. E. Reina's edition of Buridan's Tractatus de suppositionibus (1959) and H. Hubien's edition of Buridan's Tractatus de consequentiis (1976). Both of these treatises are advanced works on logic and on philosophy of logic. Roughly speaking, the former lays out a theory of reference, the latter a theory of inference conditions. Peter King's own Introduction (3-82) and about forty single-spaced pages of very informative notes (327-65) go a long way towards a better understanding of problems the way Buridan saw them and of solutions he offered. King stresses the central importance of Buridan's mental language, which is also a "canonical language, an ideal or logically perfect language" (xo) in which there are neither ambiguous nor synonymous terms. The concept of equiformity is developed and Buridan readily admits the existence of equiform expressions, but not of equiformity as such. Two forms of the copula, 'is' and 'is not', are recognized by Buridan as primitive (cf. ~7). King also shows the importance of appellation of terms, he touches on the metaphysical considerations of the modes of adjacence of properties to things and points out Buridan's effort to avoid Bradley's regress; in addition he makes a number of useful remarks about intensional verbs and the opaque contexts created by them. Related to Frege's view is Buridan's claim that no part of an assertion is itself an assertion. Again, "All swans are white" is not thought of as a disguised conditional, but rather "as something like 'Consider the swans: each is white'.., where 'consider the BOOK REVIEWS 663 swans'.., captures the assertive force of a sentence" (25). Hence, the corresponding particular affirmative sentence is entailed by the universal. On the other hand, no negative categorical sentence entails existence, and any negative is true either if the predicate does not apply to the subject or else if the subject term is empty. What is especially novel in King's discussion of supposition is his stress on the medieval use of anaphoric relative pronouns whose antecedents are quantified terms. Furthermore, he makes a plausable nominalistic interpretation of Buridan's natural supposition in sentences of natural science such as 'Thunder is a sound in the clouds', and he points out that "Buridan specifically rejects the conditional reading of such sentences" (44)While modern logicians tend to reduce de re to de dicto modality, medieval logicians, including Buridan, often did the reverse. Buridan considered modal sentences to be primitive, not reducible to categorical sentences of present time...