C. D. Broad
Charlie Dunbar Broad  (30 December 1887 – 11 March 1971), usually cited as C. D. Broad, was an English epistemologist, historian of philosophy, philosopher of science, moral philosopher, and writer on the philosophical aspects of psychical research. He was known for his thorough and dispassionate examinations of arguments in such works as Scientific Thought (1923), The Mind and Its Place in Nature (1925), and Examination of McTaggart's Philosophy (2 vols., 1933–1938). Broad's essay on "Determinism, Indeterminism, and Libertarianism" in Ethics and the History of Philosophy (1952) introduced the philosophical terms occurrent causation and non-occurrent causation, which became the basis for the contemporary distinction between "agent-causal" and "event-causal" in debates on libertarian free will.