Arthur Prior

Arthur Prior

Arthur Norman Prior
Born 4 December 1914
Masterton, New Zealand
Died 6 October 1969
Trondheim, Norway
Era 20th-century philosophy
Region Western Philosophy
School Analytic philosophy
Main interests
Temporal logic, modal logic
Notable ideas
Tense logic

Arthur Norman Prior, also known as A. N. Prior, (1914–1969) was a noted logician and philosopher. Prior (1957) founded tense logic, now also known as temporal logic, and made important contributions to intensional logic, particularly in Prior (1971).


  • Biography 1
  • Publications 2
  • References 3
  • Further reading 4
  • External links 5


Prior was born in Masterton New Zealand, 4 December 1914, the only child of Australian-born parents: Norman Henry Prior (1882-1967) and his wife born Elizabeth Munton Rothesay Teague (1889-1914). His mother died less than 3 weeks after his birth and he was cared for by his father's sister. His father, a medical practitioner in general practice, remarried in 1920 and there were three more children.

Prior was educated entirely in New Zealand, where he was fortunate to have come under the influence of John Niemeyer Findlay. Despite knowing only modest mathematics, he began teaching philosophy and logic at Canterbury University College in 1946, filling the vacancy created by Karl Popper's resignation. 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 past, present and future are basic ontological categories of fundamental importance for our understanding of time and the world. 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, and Prior's enthusiasm is believed to have contributed materially to its revival. From 1959 to 1966, he was Professor of Philosophy at the University of Manchester, having taught Osmund Lewry. From 1966 until his death he was Fellow and Tutor in philosophy at Balliol College, Oxford. His students include Max Cresswell, Kit Fine, and Robert Bull.

Almost entirely self-taught in modern formal logic, Prior published his first paper on logic in 1952, when he was already 38 years of age, shortly after discovering the work of Józef Maria Bocheński and Jan Łukasiewicz, very little of whose work was then translated into English. He went on to employ Polish notation throughout his career. Prior (1955) distills much of his early teaching of logic in New Zealand. Prior's work on tense logic provides a systematic and extended defence of a tensed conception of reality in which material objects are construed as three-dimensional continuants which are wholly present at each moment of their existence.

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 intentionality commanded little interest in the English speaking world, and had even come under sharp attack by Willard Van Orman Quine.

He is now said to be the precursor of hybrid logic.[1] 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.


The following books were either written by Prior, or are posthumous collections of journal articles and unpublished papers that he wrote:

  • 1949. Logic and the Basis of Ethics. Oxford University Press (ISBN 0-19-824157-7)
  • 1955, 1962. Formal Logic. Oxford University Press.
  • 1957. Time and Modality. Oxford University Press. based on his 1956 John Locke lectures.
  • 1962. "Changes in Events and Changes in Things". University of Kansas.
  • 1967. Past, Present and Future. Oxford University Press.
  • 1968. Papers on Time and Tense. Oxford University Press.
  • 1971. Objects of Thought. Edited by P. T. Geach and A. J. P. Kenny. Oxford University Press.
  • 1976. The Doctrine of Propositions and Terms. Edited by P. T. Geach and A. J. P. Kenny. London: Duckworth.
  • 1976. Papers in Logic and Ethics. Edited by P. T. Geach and A. J. P. Kenny. London: Duckworth.
  • 1977. Worlds, Times and Selves. Edited by Kit Fine. London: Duckworth.
  • 2003. Papers on Time and Tense. Second expanded edition by Per Hasle, Peter Øhrstrøm, Torben Braüner & Jack Copeland. Oxford University Press.


  1. ^ Walter Carnielli; Claudio Pizzi (2008). Modalities and Multimodalities. Springer. p. 181.  

Further reading

The nearest thing to a biography of Prior is:

  • Copeland, B. J., 1996, "Prior's Life and Legacy," in his edited volume Logic and Reality: Essays on the Legacy of Arthur Prior, New York: Oxford University Press (pp. 519–32 of this volume contain a complete bibliography of Prior's known writings as of date).

An excellent survey of Prior's life and achievement is:

  • A. J. P. Kenny 1970, 'Arthur Norman Prior (1914–1969)' Proceedings of the British Academy 56: 321–349.

External links

  • Arthur Prior entry by B. Jack Copeland in the Stanford Encyclopedia of Philosophy
  • Foundations of Temporal Logic The WWW-site for Prior-studies
  • On Prior's Tense Logic by Patrick Blackburn
  • Arthur Prior Centenary Conference, Balliol College, Oxford, 21 – 22 August, 2014