Self-taught logician known for founding tense logic or temporal logic, as well as contributing greatly to intensional logic.
He was educated in New Zealand, where he was mentored by South African philosopher John Henry Niemeyer Findlay.
He was an advocate of American philosopher Charles Sanders Peirce's work.
He was married to Mary Prior.
He was also passionate about the work of John Locke and often gave lectures on Locke's life and philosophical achievements.