Louis Auguste Paul Rougier (; 10 April 1889 – 14 October 1982) was a French philosopher. Rougier made many important contributions to epistemology, philosophy of science, political philosophy and the history of Christianity. Early life Rougier was born in Lyon. Debilitated by pleurisy in his youth, he was declared unfit for service in World War I and devoted his adolescence to intellectual pursuits. After receiving the agrégation in philosophy from the University of Lyon, Rougier taught until 1924 at various lycées and obtained his doctorate from the Sorbonne in 1920. His doctoral thesis work was published that year as La philosophie géometrique de Poincaré and Les paralogismes du rationalisme. Rougier already had several publications to his name, however, beginning with a 1914 paper on the use of non-Euclidean geometry in relativity theory. Career Rougier taught in Algiers from 1917 to 1920 and then in Rome from 1920 to 1924. His first university appointment in France was at the University of Besançon in 1925, where he served on the faculty until his dismissal in 1948 for political reasons. Further university appointments were in Cairo from 1931 to 1936, the New School for Social Research from 1941 to 1943 and the Université de Montréal in 1945. Rougier's final academic appointment was to the Université de Caen in 1954, but he retired at the age of 66 after only one year there. Death Rougier lived to the age of 93 and was survived by his third wife, Lucy (née Herzka) Friedmann (1903–1983). Dr. Friedmann, whom he married in 1942, was a former secretary to Moritz Schlick. Although Friedman had a daughter from a previous marriage, Rougier himself had no children. Philosophy Under the influence of Henri Poincaré and Ludwig Wittgenstein, Rougier developed a philosophy based on the idea that systems of logic are neither apodictic (i.e., necessarily true and therefore deducible) nor assertoric (i.e., not necessarily true and whose truth must therefore be induced through empirical investigation). Instead, Rougier proposed that the various systems of logic are simply conventions that are adopted based on contingent circumstances. That view, which implies that there are no "objective" a priori truths that exist independently of the human mind, closely resembled the logical positivism of the Vienna Circle. Many members of that group, including Philipp Frank, greatly admired Rougier's 1920 work Les paralogismes du rationalisme. Rougier soon became the group's only French associate and formed close personal