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 libertarianfree will.
In 1911, he became a Fellow of Trinity College. This was a non-residential position, which enabled him to also accept a position he had applied for as an assistant lecturer at St Andrews University. He was later made a lecturer at St Andrews University, and remained there until 1920. He was appointed professor at Bristol University in 1920, and worked there until 1923, when he returned to Trinity College as a College lecturer. He was a lecturer in 'moral science' in the Faculty of philosophy at Cambridge University from 1926 until 1931. In 1931, he was appointed 'Sidgwick Lecturer' at Cambridge University. He kept this role until 1933, when he was appointed Knightbridge Professor of Moral Philosophy at Cambridge University, a position he held for twenty years, until 1953.
Broad was openly homosexual at a time when homosexual acts were illegal. In March 1958, Broad along with fellow philosophers A.J. Ayer and Bertrand Russell, writer J.B. Priestley and 27 others sent a letter to The Times which urged the acceptance of the Wolfenden Report's recommendation that homosexual acts should 'no longer be a criminal offence'.
Broad argued that if research showed that psychic events occur, this would challenge philosophical theories of "basic limiting principles" in at least five ways:
Backward causation, the future affecting the past, is rejected by many philosophers, but would be shown to occur if, for example, people could predict the future.
One common argument against dualism (that is, the belief that while bodies are physical entities, minds are a different, non-physical sort of entity) is that physical and non-physical things cannot interact. However, this would be shown to be possible if people can move physical objects by thought (telekinesis).
Similarly, philosophers tend to be skeptical about claims that non-physical 'stuff' could interact with anything. This would also be challenged if minds are shown to be able to communicate with each other, as would be the case if mind-reading is possible.
Philosophers generally accept that we can only learn about the world through reason and perception. This belief would be challenged if people were able to psychically perceive events in other places.
Physicalist philosophers believe that there cannot be persons without bodies. If ghosts were shown to exist, this view would be challenged.
In his essay "Determinism, Indeterminism, and Libertarianism", Broad argued for "non-occurrent causation" as "literally determined by the agent or self." The agent could be considered as a substance or continuant, and not by a total cause which contains as factors events in and dispositions of the agent. Thus our efforts would be completely determined, but their causes would not be prior events.
New series of events would then originate which he called "continuants." These are essentially causa sui.