Glassen's first set of publications consisted in eight papers published in major philosophical journals in 1957, 1958 and 1959. These reflected his core interests: analytic moral theory (where he was a
cognitivist and champion of
ordinary language analysis),
value theory (particularly the classification of, and distinctions among, moral and non-moral varieties of normative judgment), and
epistemology (notably the question of the possibility of
synthetic a priori knowledge). There followed a period of reduced activity, with two papers on cognitivism in 1962 and 1963, several reviews for
Dialogue from 1963 to 1970, and finally a series of papers on another subject of enduring interest—the refutation of arguments against
dualism—between 1976 and 1984. Glassen also authored a number of conference papers, including two that were published in the proceedings of the 12th and 13th meetings of the
International Congress of Philosophy, in 1958 and 1963 respectively. Several other papers were unpublished and—with one or two exceptions—are likely lost. In 1961, Glassen travelled to England on a
Canada Council grant, meeting with many leading moral philosophers of the time, including
Sir David Ross,
H. B. Acton and others. Glassen's early promise was not entirely realized. This was at least partly due to the lasting effects of a personal tragedy. While returning from
Toronto to
Winnipeg for the beginning of the 1965–66 school year, Glassen was involved in a car accident that took the life of the other driver. Though not ultimately found at fault, Glassen never fully recovered from the shock. His scholarly output declined and he turned down an opportunity to move to the more prominent department at the
University of Toronto in 1967. His career might have faded into complete obscurity had it not been for the development of
eliminative materialism by fellow
University of Manitoba philosophers
Paul Churchland and
Patricia Churchland in the 1970s. This aroused his vehement opposition and revived his interest in writing and publishing. After several years of good health, a series of illnesses in 1985-86 brought on a recurrence of depression and alcoholism, leading to his death by suicide on or about March 24, 1986 in
Winnipeg. ==List of known writings==