Academic and noted emeritus Professor of Philosophy at the University of Toronto.
He received his Ph.D. from the University of Pittsburgh in 1973.
He was able to prove the undecidability of the relevance logic R, one of his most important and significant achievements.
He was born in Scotland and attended the University of Edinburgh from which he earned his Master's in 1967.
He and athlete Tony Dorsett both studied at the University of Pittsburgh.