William of Sherwood (1200/1210–1266/1271)

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William of Sherwood, or Shyreswood, was an English logician. All that is known for certain of William of Sherwood's life is that in 1252 he was a master at Oxford, that he became treasurer of the cathedral church of Lincoln soon after 1254, that he was rector of Aylesbury and of Attleborough, that he was still living in 1266, and that he was dead in 1271. From references in his works, however, and from the fact that his logic almost certainly had a direct influence on the logical writings of Peter of Spain, Lambert of Auxerre, Albert the Great, and Thomas Aquinas, all of whom were at Paris around the same time, it seems undeniable that he taught logic there from about 1235 to about 1250.

William's impact on his contemporaries went unacknowledged except by Roger Bacon, who, in his Opus Tertium (1267), described him as "much wiser than Albert [the Great]; for in philosophia communis no one is greater than he." Bacon's phrase philosophia communis must refer to logic; no other kind of work can be definitely attributed to William, and his logical works certainly were influential. They consist of an Introductiones in Logicam, a Syncategoremata, a De Insolubilibus (on paradoxes of self-reference), an Obligationes (on rules of argument for formal disputation), and a Petitiones Contrariorum (on logical puzzles arising from hidden contrariety in premises). Only the first two were ever published; they are longer and far more important than the last three. A commentary on the Sentences, a Distinctiones Theologicae, and a Conciones (a collection of sermons) have also been attributed to William, though their authenticity is seriously questioned.

The Introductiones consists of six treatises, the first four and the last one of which correspond (very broadly) to Aristotle's De Interpretatione, Categories, Prior Analytics, Topics, and Sophistical Refutations, in that order. The third treatise contains the earliest version of the mnemonic verses for the syllogism "Barbara, Celarent ," and there are other interesting minor innovations in those treatises. The most important novelties are concentrated in the fifth treatise, "Properties of Terms"; it contains the logico-semantical inquiries that gave the terminist logicians their name. William recognizes four properties of termssignificatio, suppositio, copulatio, and appellatio. The last three may be very broadly described as syntax-dependent semantical functions of a term's significatio, which is its meaning in the broadest sense.

In order to distinguish such medieval contributions from strictly Aristotelian logic, thirteenth-century philosophers spoke of them as logica moderna. When William wrote, logica moderna was thought of as having two branches, proprietates terminorum and syncategoremata. In his separate treatise on the latter, William investigates the semantical and logical properties of such syncategorematic words as every, except, only, is, not, if, or, necessarily. Both branches may be said to be concerned with the points of connection between syntax and semantics and with the effect those points have on the evaluation of inferences. William's treatment of both is marked by a concern with the philosophical problems to which they give rise.

The ingredients of the logica moderna certainly antedate William's writings, but his may very well be the earliest full-scale organization of those elements in the way that became characteristic of medieval logic after his time.

See also Albert the Great; Aristotle; Bacon, Roger; Logic, History of; Medieval Philosophy; Peter of Spain; Semantics, History of; Thomas Aquinas, St.


Martin Grabmann has edited Die Introductiones in logicam des Wilhelm von Shyreswood, Literarhistorische Einleitung und Textausgabe in Sitzungsberichte der Bayerischen Akademie der Wissenschaften, Philosophische-historische Abteilung, Jahrgang 1937, Vol. 10 (Munich, 1937). Norman Kretzmann has translated William of Sherwood's Introduction to Logic (Minneapolis: University of Minnesota Press, 1966), and J. Reginald O'Donnell has edited "The Syncategoremata of William of Sherwood" in Medieval Studies 3 (1941): 4693.

Norman Kretzmann (1967)

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William of Sherwood (1200/1210–1266/1271)

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