Prior was educated entirely in New Zealand, where he was fortunate to have come under the influence of
J. N. Findlay, While Prior was very fond of the theology of
Karl Barth, his early criticism of Barth's adherence to
philosophical idealism, is a mark of Findlay's influence on Prior. He became Professor in 1953. Thanks to the good offices of
Gilbert Ryle, who had met Prior in New Zealand in 1954, Prior spent the year 1956 on leave at the
University of Oxford, where he gave the
John Locke lectures in philosophy. These were subsequently published as
Time and Modality (1957). This is a seminal contribution to the study of tense logic and the
metaphysics of time, in which Prior championed the
A-theorist view that the temporal modalities of past, present and future are basic
ontological categories of fundamental importance for our understanding of time and the world. Prior was several times warned by
J. J. C. Smart against making tense-logic the topic of his
John Locke lectures. Smart feared that tense-logic would get Prior "involved in side issues, even straight philosophy, and not in the stuff that will do Oxford most good." Prior was however convinced that tense-logic had the potential to benefit logic, as well as philosophy, and thus he considered his lectures an "expression of a conviction that formal logic and general philosophy have more to bring to one another than is sometimes supposed". During his time at Oxford, Prior met
Peter Geach and
William Kneale, influenced
John Lemmon, and corresponded with the adolescent
Saul Kripke. Logic in the United Kingdom was then in a rather low state, being "deeply out of fashion and its practitioners were isolated and somewhat demoralized." Prior arranged a Logical Colloquium which brought together such logicians as
John Lemmon,
Peter Geach,
Czesław Lejewski and more. The colloquiums were a great success and, together with Prior's John Locke lecture and his visits around the country, he helped revitalize British logic. when he was 38 years of age, shortly after discovering the work of
Józef Maria Bocheński and
Jan Łukasiewicz, despite very little of Łukasiewicz's work being translated into English. He went so far as to read untranslated Polish texts without being able to speak Polish claiming "the symbols are so illuminating that the fact that the text is incomprehensible doesn’t much matter". Prior (1955) distills much of his early teaching of logic in New Zealand. Prior's work on tense logic provides a systematic and extended defense of a tensed conception of
reality in which propositional statements can change truth value over time. Prior stood out by virtue of his strong interest in the
history of logic. He was one of the first English-speaking logicians to appreciate the nature and scope of the logical work of
Charles Sanders Peirce, and the distinction between
de dicto and
de re in
modal logic. Prior taught and researched
modal logic before Kripke proposed his
possible worlds semantics for it, at a time when modality and intensionality commanded little interest in the English speaking world, and had even come under sharp attack by
Willard Van Orman Quine. His work is now said to be the precursor of
hybrid logic. Undertaking (in one section of his book
Past, Present, and Future (1967)) the attempt to combine binary (e.g., "until") and unary (e.g., "will always be") temporal operators to one system of
temporal logic, Prior—as an incidental result—builds a base for later hybrid languages. His work
Time and Modality explored the use of a
many-valued logic to explain the problem of
non-referring names. Prior's work was both philosophical and formal and provides a productive
synergy between formal innovation and linguistic analysis.
Natural language, he remarked, can embody folly and confusion as well as the wisdom of our ancestors. He was scrupulous in setting out the views of his adversaries, and provided many constructive suggestions about the formal development of alternative views. He possessed an intellectual purity and a devotion to the subject that I immediately recognized and have always attempted to emulate (
Kit Fine) ==Publications==