Hugues Leblanc

Hugues Leblanc, philosopher and logician (born 19 March 1924 in Sainte-Marie de Beauce, Québec; died 10 September 1999 in Rockville, Maryland). A philosopher with an international reputation, he was one of the best logicians that Canada ever produced. After completing his master’s degree at Université de Montréal, he went to the United States to continue his training in mathematical logic. He completed his doctoral studies at Harvard University under the eminent philosopher Willard V.O. Quine and received his Ph.D. in 1948.

Leblanc then pursued his academic career in the philosophy departments of two prestigious institutions in the Philadelphia area: first at Bryn Mawr College (until 1967) and then at Temple University. Upon retiring from Temple, Leblanc accepted a position as an associate professor in the philosophy department at Université du Québec à Montréal, where he conducted intensive research until failing health forced him to stop in late 1996. This research led to the publication of his last book, Probability Theory and Probability Logic (University of Toronto Press, 1999), written in collaboration with Peter Roeper, who had previously worked with Leblanc on several of his most important studies on probabilistic semantics.

Leblanc was interested mainly in free logic, which differs from classical logic in that it does not assume that the names that it uses refer to anything real. Free logic also differs from verifunctional semantics (semantics based on the concept of truth value, classical semantics assuming two possible truth values: true and false). But he was also interested in probabilistic semantics and probability theory in general.

In addition to Probability Theory and Probability Logic, Leblanc published three other books: Statistical and Inductive Probabilities (1962), Truth-Value Semantics (1976) and Existence, Truth and Probability (1982). He co-authored two other works; one of them, Deductive Logic, written with W.A. Wisdom (1972), has become a very well known manual of logic.

Leblanc received a Fulbright Fellowship (1953-1954) and a Guggenheim Fellowship (1965-1966), as well as honorary doctorates from Université de Montréal (1980) and Dalhousie University (1982). He was the second recipient of the Université du Québec à Montréal Certificate for Scientific Merit (1985). He and Mario Bunge co-founded the Society for Exact Philosophy (1971). In 1982, Leblanc received the Paul W. Eberman Faculty Research Award from Temple University.