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This is the electronic edition of Per Hasle, "Life And Work of Arthur N. Prior - An Interview with Mary Prior". Workpaper 72-98, Centre for Cultural Resarch, University of Aarhus,1998.

The pagination of the printed edition is indicated by red numbers marking the beginning of the page.

ISBN: 87-7725-221-7

Electronically published: October 15, 1998

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'Life and Work of Arthur N. Prior. An Interview with Mary Prior'

Given at Mary Prior's home in Oxford, Sunday 5th October 1997.

Interviewer: Per Hasle  

Introductory Notes

This interview with Dr. Mary Prior, widow of Arthur Norman Prior (1914-1969), is concerned partly with the life of the Priors', and partly with the philosophy and opinions of Arthur Prior. The questions were conceived by Per Hasle and are structured with a view to two purposes: the interview should be able to stand as an independent source towards its subject, and at the same time it should supplement the major existing papers on Arthur Prior's life and work, namely Kenny (1970), øhrstrøm and Hasle (1993), Copeland (1996), and Hasle (1997).

Mary Prior has answered the questions in writing as well as in an interview conducted in her home in Oxford on 5th october 1997. It may be mentioned that the interview begins with a general remark by Mary Prior, rather than with a question. The interview was recorded on digital video by Peter øhrstrøm, and selected parts from it can be seen at 'The WWW-site for Prior-studies' under The text below is based on the written answers, but is very close to the recorded version.

Thanks to Mary Prior for giving this interview and to Peter øhrstrøm for useful comments on the questions as well as for holding the camera. --- Per Hasle, Aarhus, 19th May 1998.


MP: It is now 53 years since Arthur and I met, and 28 years since Arthur died, so I am recalling the distant past. Sometimes it seems vivid and close, sometimes far off, another world, so my memory is very uneven. This is particularly true of Arthur's work, because though my initial training was in philosophy, even before Arthur's death I moved into history, and though during Arthur's life I could follow his work, I did not realize until after he died how much in his last years as his work got more technical I leaned on him to explain it. I had stopped standing on my own philosophical feet as I began to become preoccupied with finding my feet as a historian.

Mrs. Prior, you first met Arthur Norman Prior, your future husband, in 1943. Can you tell us about your first meeting, and something about your own and Arthur's backgrounds before that ?

Arthur and I met on the last day of a Student Christian Movement conference in Christchurch. It was during the war and Arthur was stationed at a nearby Air Force Station. I had just finished my BA. He had graduated in the thirties, failing to gain the scholarship which would have led to postgraduate study abroad. He had nevertheless been to England. He belonged to a generation of students noted for their intellectual brilliance. I was very impressed. On this first occasion we talked almost non-stop for over five hours - philosophy, theology, gossip - lively and great fun. It was an immediate rapport of two people who saw their lives as very different. And yet our backgrounds were very similar. We both had nonconformist clergy in our families, doctors, nurses and missionaries.

Please tell us about your first years together, and Arthur's interests during that period. We got engaged after meeting four times and married seven


months later. After the birth of our son Martin, Arthur was posted as a wireless mechanic to the New Hebrides. Most reading matter was supplied by the American Navy. He read a lot of Herman Melville and Nathaniel Hawthorne and wrote love letters daily as did I. I don't know if he had any theological works with him, but he discussed theological problems in some of them.

On his return he applied for and got the job in Christchurch as a temporary assistant lecturer as a stop-gap as Popper had just vacated the lectureship. Before we moved to Christchurch our house burnt down and we lost all our possessions. A few precious books were rescued in a charred condition and rebound.

Christchurch was a wonderful place to be in those earliest years. Returned servicemen and former conscientious objectors filled the classrooms along with people straight from school. The distinction between staff and students can never have been less. It was a period when everyone was catching up on lost years. For Arthur it meant preparing courses of lectures in logic, ethics, the philosophy of Plato and Aristotle, Locke, Berkeley and Hume; Kant and Hegel, Mill and other 19th century English speaking philosophers. Philosophy was then part of a joint Psychology and Philosophy stage course, in which Logic and Ethics and one year of psychology were common to psychologists and philosophers in a 9 unit degree. (As I remember it). A more advanced logic course and specialist subject - e.g. Plato and Aristotle. The special subject rotated. As all the philosophy teaching fell to Arthur he refused to teach the Kant and Hegel option. He did not speak German and had a distaste for Hegel. Interestingly, two of his abler students Evan Jonathan and Gillian Bennett (née Quentin-Boxter) were to develop a strong interest in German philosophy!

During this period 1946 to early 1949 we lived in Macmillan Avenue on Cashmere Hill. Every Saturday morning Arthur took a tutorial lecture with his class, as did a neighbour Henry Broadhead. Usually Arthur biked to work, but on Saturdays Dr. Broadhead and Arthur drove together in Dr. Broadhead's car and then came back to our flat for coffee. Broadhead and


Popper had been friends and I have no doubt their conversation was largely on Greek philosophy. Broadhead was about 15-20 years older than Arthur, and had I think been to Cambridge. I suspect Arthur's interest in early philosophy was fuelled by Broadhead.

In 1949, Arthur Prior was writing a book called "A History of Scottish Theology". But that same year your house burned down and the manuscript was damaged (one can still see the signs of burns on the manuscript now deposited in the Bodleian Library). You have yourself characterised this occasion as a turning point, after which Arthur Prior gave up that project, and increasingly turned his interest towards logic. Can you tell us about the project which was given up, and how and why Arthur's interests changed from that time on?

At this time Arthur was writing Logic and the Basis of Ethics [Prior 1949], which drew on material from the courses he was teaching. Although he still from time to time returned to his History of Scottish Theology, work coming out of his teaching commitments was taking over. The main thing I remember him doing connected with the History was ordering and reordering the table of contents. What was to be the order of God's Decrees for instance? I don't think he ever came to a conclusion. When a second fire once again destroyed our property together with others in the pleasant old wooden house in which we lived, material for the book was destroyed, and the project was never resurrected. A few somewhat charred remnants of material from this period survives in the Bodleian. Scottish theology remained however part of the mulch which nourished his work.

One important occasion in Arthur Prior's intellectual development was obviously his participation in the 1951 Philosophical Congress in Sydney. Please give us some impressions from the conference, and tell us about its influence on Arthur.


In 1949 we moved house twice before buying a house in Grange Street, Opawa. Arthur was able to present me with an advance copy of Logic and the Basis of Ethics on the morning our second child Ann was born. At this time we lived isolated from other philosophers, save by letter. Arthur found stimulation from his students, and this was to continue all his life even when no longer isolated. We scraped to go to the 1951 Meeting of the Australasian Philosophy and Psychology Society. There were no grants towards such things in those days. We were amazed when Jack Smart, freshly out from Oxford, strode across the room to congratulate Arthur on Logic and the Basis of Ethics, which he announced was being much discussed in Oxford. At this conference we met any Australian Philosophers, and became aware of the division between Andersonian philosophers in Sydney and Melbourne philosophers.

In Adelaide he lived outside the storm centre, as did Arthur. We formed long lasting friendships with Jack [Smart] and with John Mackie (the independent minded Sydney philosopher). I still keep in touch with Jack and Joan, John's widow and I meet regularly. This conference ended a period of near isolation. Jack, then a bachelor, came to several NZ philosophy conferences, several other Australian philosophers came occasionally. The first NZ conference was held in Christchurch in 1953. Through Jack, Arthur was also put in touch with English philosophers, and when Jonathan Bennett went to Oxford to do a B. Phil. in 1954, his long gossipy letters made them live. In late 1954 Gilbert Ryle visited NZ and brought in his pocket an invitation [for Arthur Prior to give the John Locke lectures in the University of Oxford in 1956].

Already in 1951, there were a few suggestions in Arthur Prior's manuscripts to the effect that there could be a 'logic of time-distinctions'. But evidently it was not till 1953 that he started working on this project, which was to become his most noted achievement. Apparently a footnote by Findlay inspired him to take up this issue in earnest. Please tell us about this event.


The idea a logic of time distinctions may well have simmered in Arthur's head long before 1951, for it was in the Australasian Journal, December 1941, that John Findlay's paper 'Time: A Treatment of some Puzzles' [Findlay 1941] first appeared. However, it became more widely available when it was reprinted in Tony Flew's Logic and Language, 1951 [Flew 1951]. But it was probably as late as in 1954 or early 1955, perhaps when he was working on the John Locke lectures that he came and sat on the bed in high excitement. He read the all important footnote. He felt he could formalise tense distinctions, drawing inspiration from this footnote of Findlay's. I date this from the fact that I have a vivid memory of the event occurring in a sunporch in the house we moved into in mid 1954.

The idea that logic and time should be related to one another was certainly a novelty at that time. What can be said about Arthur Prior's relation to mainstream logic and perhaps more generally, to analytical philosophy?

I hesitate to answer this, because I feel I may misrepresent Arthur, but I think I'm right in saying that Arthur initially accepted Russell and Whitehead as establishing the parameters of modern logic; developed doubts as he read more ancient and medieval logicians, and then sought to formalize a tensed logic which would deal with tensed statements. As for analytical philosophy, he thoroughly enjoyed crossing swords with analytical philosophers - it was endemic in Oxford - and used to return home from dinner in Oxford colleges, when we were there, flushed with the pleasure of combat. His paper 'The Runabout Inference Ticket' [Prior 1960] is his most accessible thing on this subject, though perhaps I'm biased as I suggested the title.

Another notable feature of Arthur Prior's work in logic was his great historical awareness. He obviously had a comprehensive knowledge of Ancient and Medieval philosophers and logicians, and found their discussions fruitful also for a present-day study of logic. Can you tell us more


about his views on the importance of studying the history of logic?

I suspect that Findlay laid the groundwork of Arthur's interest in ancient and medieval logic, and Broadhead furthered it. But it was fairly dormant until the early 1950s, when he had papers in Dominican Studies (1952), Franciscan Studies and The New Scholasticism. I don't know what set him going, probably the work of Bochenski, La Logique de Theophraste 1947 [Bochenski 1947]. He was impressed by the rigorous formalisation of medieval logic and by the work of the Polish School of logicians (which included Bochenski) at roughly the same time. Articles on both appeared in 1952, and marked a new departure. His work had always taken the work of philosophers of the past as worth listening to, and to be taken seriously. The past had a democratic right to speak to the present. 1952 was the beginning. He had yet to meet others working in that field, but he was in correspondence with them now.

1954 was a difficult year for your family, you yourself going to hospital for some time, and your children being ill, too. What are your recollections of that year?

Yes, 1954 was a difficult year. The family seemed to be always ill in the years before that - measles, mumps, whooping cough. The things children bring back from school in the first year or two. I was often ill. It turned out that I had TB and passed it on to the kids. I spent 9 months in a Sanatorium nearby, the children were nursed at home by a trained nurse. Arthur fitted in when she was off duty and visited me faithfully twice a week as well as lecturing and writing me daily letters. The university was understanding and excused him all committee meetings. How he coped I do not know. For the children being nursed at home spared them the desolation of hospital life, and despite being confined to bed they seemed to manage to have a jolly time. Arthur was a Pied Piper with children, the two successive nurses were splendid and my parents provided back up from time to time. They lived 100 miles away in



In 1956, you went to Oxford, where Arthur Prior had been invited to give the John Locke lectures that year. Many important contacts were made during that year, and in particular, Arthur Prior arranged the 1956 Oxford Logic colloquium. Please tell us about this year in Oxford, and the colloquium.

When Gilbert Ryle visited Christchurch in late 1954, he brought an invitation to Arthur to read the John Locke lectures in Oxford. This unlocked many doors when we got there in 1956. Arthur was widely dined by established philosophers, mainly in the analytical tradition. Logicians were few on the ground. Dummett was away in America most of the year. However, contact was made with those around, like Bill and Martha Kneale. Some whose work was most important to Arthur were only marginally connected to the University. The Dominican monk, Ivo Thomas at Blackfriars, John Lemmon still a very junior fellow, Peter Geach, commuting between his job in Birmingham and Oxford, where his wife Elizabeth Anscombe had a fellowship at Somerville.

The John Locke lectures were formal occasions without any opportunity for discussion, so Arthur organised a discussion at our flat once a week, attended by Ivo, John, and Peter when he could manage it, plus occasional attenders, often postgraduate students.

Arthur met other logicians in the spring and early summer, and the idea of a colloquium in late summer was mooted. A small ad hoc committee was formed, and Marcus Dick arranged for a lecture room at Balliol. Almost everyone invited turned up. It lasted the best part of two days. [At] a punting party the last afternoon - Ivo, Arthur and John Lemmon and the Merediths from Dublin (Carew and David) started work on a first paper (on calculi of implication) published in 1969 but circulated in MS form many years, known as LMMPT - the initials of the authors [Prior 1969]. The conference ended with a party at our flat. So many people were meeting for the first time and talked logic with urgency. The decibel level was high.


The flat was small in the gables of the house (8 Park Town) and sound bounced off the sloping walls. Tall men bent almost double. Much beer was drunk and Pat Lemmon and I rushed around with cheesy toast and twiglets. In those days - rationing was recently ended - entertaining was simple and undemanding.

What was Arthur Prior's way of working, his attitude towards colleagues and students? How would you characterise him as a person?

Arthur worked intensely, often through the night. He seldom corrected a paper or made insertions. He might revise his opinion on a subject as he wrote, and would then be most likely to start again rather than fiddle with it. When he relaxed he wanted to do things which left his brain just ticking over. He never played bridge or other games involving thinking. He played with his children, went walking, and, after we came to England, engaged in canal cruising. Canal cruises often included friends like Tony Kenny (whom we got to know when we moved to Manchester). Tony at that time was a Roman Catholic priest in Liverpool, which is not far from Manchester - see Tony's A Path from Rome [Kenny 1985]. We bought a cottage in Shropshire and every summer exchanged visits with Peter Geach and Elizabeth Anscombe, who had a place at the other end of the country. A good deal of philosophy was often mixed in on such occasions. Arthur enjoyed philosophical conversations with colleagues enormously, and this included students as much as anyone else. He also enjoyed trying out philosophical puzzles on children. This tended to infuriate Ann who in frustration might punch him if it went on too long.

What sort of person was he? Spontaneous, very open. Formality made him impatient and pompous and manipulative people he despised. They were bullshit artists and dicky-lickers. Arthur retained from the airforce some ripe turns of phrase. He was a good friend but had a strong sense of the ridiculous and was no respecter of persons. He did not repress his feelings and occasionally lost his temper dramatically. He was not a stoic. Life with him was enormous fun. I think for this


reason our fires and the TB episode ended up by being remembered largely for the bizarre situations they landed us in.

Before going on with milestones in your lives, we wish to discuss Arthur Prior's views and philosophical interests more closely. First of all, it seems that existential questions were for him a subject relevant to logic, and conversely. What was his conception of logic in general?

I find answering questions about the content of Arthur's thought particularly difficult. Partly this is because it is so long since I have been seriously involved in philosophy, and partly because I was so close to it, and it's hard to see the wood for the trees. For Arthur's thought and interests did change over time. I find too I now fumble for the right technical terms.

Jack Copeland prefaces his collection of essays on Arthur's legacy, Logic and Reality [Copeland 1996] with a quote from Arthur which in full reads: 'Philosophy, including logic, is not primarily about language, but about the real world'. Logic was a powerful tool, faulty logic led to error. "One should always keep a-hold of nurse for fear of finding something worse". [An allusion to the closing punch line from Hilaire Belloc's childrens' poem "Jim: who ran away from his nurse and was eaten by a lion".] While a logic which ignored aspects of the real world was faulty or incomplete. I put this with the crudity of a layman, but I hope I don't misrepresent him.

The concept of time and the development of tense logic were, of course, central to Arthur Prior's work. How would you sum up his ideas on 'time'?

Arthur's ideas on time altered; developed, as I have already mentioned. He sought to extend the scope of logic to accommodate such statements as the state of affair's expressed in 'Thank Goodness that's over' - the title of a paper first published in 1959 [Prior 1959]. The last page of this paper shows Arthur at his controversial and funniest best.


In his early writings, before tense logic, Arthur Prior several times dealt with the Christian - and in particular Calvinist - idea of predestination. In a similar vein, the difficult question of God's foreknowledge versus human freedom was discussed by him - the latter question in fact also in his late writings. Can you tell us about the development of his views on these issues and how they influenced his thought? A related and lasting preoccupation within Arthur's work was the problem of free will. What were his views on this matter?

Yes, it is true that Arthur was preoccupied by the problem of free will. At first he saw it in a semi-theological context. I have never felt quite sure how seriously Arthur really took the Calvinism which intellectually attracted him. It was rigorous and logical, unlike the Methodism of his childhood. But it's God lacked humanity. I think sometimes he entertained Calvinism in its various forms rather than quite believing it. He was very aware of the dilemmas it posed. Perhaps his failure to resolve them was a reason why despite so much preparation the book on Scottish Theology never came to anything. In his later work I think he was prepared to go where logic led him, but the idea of the future as open to choice, where the past and present were not, may also have had deeper emotional attractions. But here I speculate.

Recently, Arthur Prior's tense logic has been likened by some, notably Mogens Wegener, to the philosophy of Søren Kierkegaard, who also considered the notion of the 'now' to be of crucial importance. Kierkegaard, of course, took a special interest in the existential implications, whereas tense logic rather naturally emphasises the logical importance of the 'now'. But we do know that Arthur studied Kierkegaard with interest as a young man, and also wrote a bit about him. We wonder whether you can add something about Arthur's view on Kierkegaard, and the possible relation between Kierkegaard's thought and Arthur's.

I find Mogens Wegener's suggestion that Arthur's tensed logic


can be likened to that sketched by Kierkegaard fascinating. It would be interesting to know whether Arthur had read the passages in Kierkegaard in which it was developed (Philosophical Fragments and the Concept of Dread). If he read them it was when he was reading Kierkegaard as a young man and it must have lain fallow. But he read him in the years before I met him. The only work of Kierkegaard I know he possessed was a translation of Lidelsernes Evangelium (Gospel of Sufferings) which appeared in 1955. It was translated by a friend, W.S. Ferrie, a Birmingham Presbyterian clergyman. I don't know how much was accessible to Arthur pre-1943 in English or French. In this period he read a lot of European philosophy and literature. Refugees from Nazi oppression were flooding into England, and some even reached New Zealand providing a rich leaven to intellectual life.

Arthur Prior also had a strong political commitment to the cause of poor and otherwise oppressed people. What were his political views, and do they relate to his thought as a philosopher and logician?

Arthur was left wing from his student days on. I think he would have felt something had gone very wrong with his philosophical and logical arguments if they had entailed a conservative viewpoint - that they had ceased to relate to the real world. Many of his friends were Marxists, but of course dialectic had no appeal because of its logical repercussions. However, I doubt if he realized this as a very young man. I think Claire, his first wife was a card carrying member of the Communist Party. She ended in middle age by emigrating to Russia.

In December 1956, you left Oxford and went back to New Zealand. About two years later, however, Arthur Prior was offered a professorship in Manchester, so in 1958 you left NZ for good. Tell us about those last two years in NZ.

Although Arthur did not take up the Manchester Chair until January 1959 - we held Christmas 1958 at sea - he had been


interviewed for a yet to be created second chair in Manchester in 1956.

The last two years in New Zealand were very much like earlier years save that Arthur's correspondence had increased enormously. We looked forward to moving back into the wider world. You must remember at that time flying was still prohibitively expensive, and the sea voyage took a month. Everything still moved at a slow pace. Now a logician in NZ is not cut off in the same way.

In this period, however, I think Arthur had become connected with the JSL [Journal of Symbolic Logic], perhaps still only one of the associate editors, and as a result received Kripke's first paper [Kripke 1959] for consideration. This was enormously exciting and was the highlight of these years. Arthur also had the stimulation during these years, and indeed, from the year or two before 1956, of meetings with John Mackie, who had come to the Dunedin Chair, and George Hughes to the Wellington Chair. They were external examiners for each other, and once the examining was done, philosophical talk continued until the small, or not so small hours. These occasions were looked forward to as much by me as Arthur - I mean the discussions - not the examining, of course.

I must correct you on one point here. We didn't leave NZ for good. Arthur lectured for the British Council for 2 months in 1965, and the rest of the family went out on a family visit.

What was it like, coming to Manchester?

Manchester? For Arthur it was very satisfying to get back to Britain, but for me it was rather lonely. One might say philosophy was more professionalized. There was less need to use our home as an auxiliary setting to the department. And Arthur had many invitations to give lectures in other departments, and even other countries, - Poland and America. As a result, from this time on my knowledge of Arthur's work is less full than formerly - and this at a time when he was becoming increasingly productive, mature and fertile in his work. However, I did attend local seminars and some were held in our house, and we put up visiting lecturers.


The relationship between staff and undergraduates was not as informal and close as in New Zealand, but Arthur had some good postgraduate students - most notably Max Cresswell and Robert Bull - both New Zealanders. And of course the opportunities for discussion with other philosophers and logicians within the department and outside it was considerable. Tony Kenny was at Liverpool for several years at this time and we saw a lot of him. Kripke visited for a week - and you should have seen me struggling with Orthodox Jewish cooking, and Arthur with getting him anywhere on time - I wonder if that's still a problem. Alan Ross Anderson came for a year, and Arthur and he continued, face to face, arguments formerly carried on over some years by letter.

In 1965, you both went to California. Apparently Arthur Prior's California lectures contributed significantly to the flourishing development in logic there at that time, and especially it seems to have sparked off a great interest in tense logic. Please give us some impressions from the California tour.

The time in California followed on after our time in New Zealand - 1965 to early 1966. For Arthur this was a tremendously exciting period. As a visiting lecturer at UCLA he was the Flint Professor - photos of what the departmental secretary called 'Our Flints' adorned the walls of the department and Arthur's photo presumably is somewhere there. As well as lecturing there he read papers in various Californian universities including Berkeley. I did not usually accompany him on these one night stands. Who he met and talked to then, I hardly know. I think at Berkeley Dana Scott and Davidson. I'm not sure if he ever met David Lewis at this time or indeed ever, though he corresponded with him. The people I remember most clearly are John Lemmon and Richard Montague. John we had known of course from 1956 and Richard from the Helsinki conference on Modal Logic a few years [later]. We used to go to the Bel Air Hotel and drink beer under the trees. And logic flowered.

In 1965, Arthur Prior was elected a fellow of Balliol College,


Oxford. He had to give up his professorship in Manchester in order to take up this position in Oxford. What were the special attractions of Oxford, and what was it like go there?

The special attraction of Oxford was that it was far more a centre for philosophy than Manchester could ever be, and Arthur came to the conclusion that postgraduate students got more stimulation there than in Manchester. And so would he.

This was perfectly true, and for Arthur the undergraduates as well as the graduate students were of the highest calibre, and then morale was high. The terrible creaming off that went on in English Universities (but not in NZ) meant that Manchester philosophy undergraduates felt they had failed the grade. That they had not been good enough. I don't think this holds any more - certainly not in science or in history.

Please tell us about your Oxford years, colleagues and students, and Arthur's main interests during that period.

The short three years in Oxford were golden years for us both. I discovered the Bodleian Library and my involvement in philosophy and logic decreased as my absorption in social history increased. This was as well. Dons' wives were expected to be fellows of colleges in their own right or mind their own business. It is still the same - maybe more so. However we still did a lot of entertaining of students and logicians and philosophers, including many from abroad.

The usual form of entertaining students in Oxford seemed to be sherry parties in College. Students tended to linger and we used to sweep up the last half dozen and take them home to eat fish and chips bought on the way home, drink coffee and continue talking.

Oxford students - undergraduate and postgraduate - were as bright as the very brightest New Zealand ones. Many were from abroad: amongst undergraduates I think of Manibhandu Sutdhisakdi, Andrew Sarrit (who moved into Art History) and Kit Fine. Among postgraduates Peter Roper and Anselm Mueller, Greg Macleod, Tony Trew, Roger Hughes (George's son), Robin Haack and his wife Susan, Bill Newton Smith (who


succeeded Arthur at Balliol). There were others whose names escape me now. Kit was the most brilliant of these students. Not all remained in philosophy and logic, but I have not followed the subsequent careers of those who did, save those I continue to see.

Not all the time was spent in talking philosophy in closed rooms. Arthur learned to drive late. Philosophy and sightseeing were often mixed. He was an erratic driver though. I remember splendid drives with visiting philosophers, such as the Kotarbinskis from Poland. Several times we took a number of students and colleagues to the White Horse in the Berkshire Downs, where we flew kites. (The 'White Horse' is a prehistoric figure cut in the chalk of the Downs). The aim was to keep the kite aloft as it was walked from the White Horse to Wayland's Smithy along the Ridgeway. It wasn't easy as there were scrubby trees to be negotiated.

In 1969, you and Arthur Prior went to Norway on a lecture tour. On this tour, in Trondheim, Arthur Prior died on 6 October. Please tell us about your impressions of this tour, and the issues with which Arthur was concerned during this tour and the last year of his life.

Just before we left for Norway where he died we had a wonderful lunch party where we seemed to gather a herd of visiting scholars. I remember Hugh Montgomery from NZ and Charles Hamblin from Australia, Dov Gabbay from Israel, R. Thomason from US, Kit Fine I think too, and several others. I think I only imagine Montague was there, as he ought to have been. Somewhere deeply buried is a postcard which everyone signed - but I cannot find it.

It was perhaps the last time Arthur was really able to forget the pains of angina and perhaps rheumatism, which dogged the last three months of his life.

On the way to Oslo he attended a conference at Oberwolfach [cf. Prior 1970] whilst Ann and I brought the heavy luggage on to Oslo by boat. He gave the first of the lectures at Oslo, but died before completing the course. He was in acute discomfort. He


felt the cold, his coat felt heavy, walking up the short steep slope to our house gave him pain. He missed the very full life of Oxford so there was little distraction from his distress. The trip to Trondheim was broken on the way by a couple of days' rest and holiday when the pain lifted. They were happy days. On arrival at Trondheim we spent the evening with local philosophers and he died during the night.

Almost immediately after Arthur's death you and Peter Geach went through his papers, notes, correspondence etc. They were deposited in the Bodleian Library, and David and Steffi Lewis further organised the papers shortly after that. Please tell us about this material, how it was collected and ordered, and what has since happened with it - for instance, the posthumous publications.

After the memorial service in Oxford which took place about three weeks later people came back in the house for drinks, and Bill Kneale took me aside and suggested I ask Peter Geach to help me cope with Arthur's papers, as he had proved himself capable in such matters - he was one of Wittgenstein's executors. Peter was there and I asked him. The only window of opportunity for some time was that weekend, and so we went down to Arthur's room at Balliol and did a vast but rapid preliminary sorting of papers and correspondence. These letters were of course letters to Arthur. Collecting letters from Arthur was more difficult. I wrote around to most likely recipients, but of course few people keep letters to the extent Arthur did. They had for long been his lifeline and were never destroyed. However, some were saved, though the only massive collection is from Alan Ross Anderson. Tony Kenny and Peter Geach edited a collection of Arthur's papers posthumously [Prior 1976b], containing some unpublished papers as well as ones published in journals, and they also cannibalised sections of the Craft of Formal Logic [Prior 1951/Prior 1976a] of a historical and critical nature. The Craft was written in 1950 and 1951 and submitted to OUP, who wanted it cut. It was excessively long and it dealt too much with Aristotelian and medieval logic, too little with modern. It


was very different from what appeared as Formal Logic [Prior 1955]. Kit Fine edited and supplemented the material for a book of which Arthur had left only one completed chapter. It draws on some of his last papers. The book, Worlds, Times and Selves [Prior and Fine 1977], continued to break new ground.

The archive has existed now for over 25 years. Only recently has it been much used, but it is a rich source not only of Arthur's work, but also because it contains so many letters from logicians and philosophers about their own work - letters written in the days when letters were the common method of communication over a distance.

Mrs. Prior, thank you very much for giving this interview.  

Works mentioned in the Interview

Bochenski, I. M.: 1947, La logique de Theophraste. Publications de l'Universite de Fribourg en Suisse. Fribourg, 1947.

Copeland, Jack: 1996, 'Prior's Life and Legacy'. In Copeland, Jack (editor): 1996, Logic and Reality: Essays on the Legacy of Arthur Prior, Oxford University Press/Clarendon Press, Oxford, pp. 1-40.

Findlay, J.N.: 'Time: A Treatment of Some Puzzles'. Australasian Journal of Psychology and Philosophy, vol. 19, 1941. (Reprinted in Flew 1951).

Flew, Antony: 1951, Essays on Logic and Language. Basil Blackwell, Oxford.

Hasle, P.: 1997, 'The Problem of Predestination - a Prelude to A. N. Prior's Tense Logic' (To appear in Wegener, Mogens (editor): Time, Creation and World-Order. 22 pages).

Kenny, Anthony: 1970, 'Arthur Norman Prior (1914-1969)', Proceedings of the British Academy, Vol. 56, pp. 321-349.

Kenny, Anthony: 1985, A Path from Rome. Sidgwick and Jackson, London.

Kripke, Saul A.: 1959, 'A completeness theorem in modal logic'. The Journal of Symbolic Logic, 24, pp. 1-14.

Prior, A. N.: 1949, Logic and the Basis of Ethics. Clarendon Press, Oxford..

Prior, A. N.: 1951, 'The Craft of Formal Logic' (unpublished manuscript, 806 pages, 1951). Found in Prior's Papers, Box 22, The Bodleian Library.

Prior, A. N.: 1955, Formal Logic. Clarendon Press, Oxford, 1955.

Prior, A. N.: 1959, 'Thank goodness that's over', Philosophy, vol. 34 (1959), pp. 12-17.

Prior, A. N.: 1960, 'The Runabout Inference-Ticket', Analysis, vol. 21 (1960), pp. 38-39.

Prior, A. N. (with E. J. Lemmon, C. A. Meredith, D. Meredith, and I. Thomas.): 1969, 'Calculi of pure strict implication'. In Philosophical Logic, ed. by J. W. Davis, D. J. Hockney, and W. K. Wilson, D. Reidel, Dordrecht, 1969, pp. 215-250. (Previously published in mimeograph form, University of Canterbury, 1957.) ('LMMPT')

Prior, A. N.: 1970, The notion of the present', Studium Generale, vol. 23 (1970), pp. 245 - 248. Reprinted in The Study of Time, ed. by J. T. Fraser, F. C. Haber and G. H. Müller, p. 320 - 323, Springer-Verlag, 1972.

Prior, A. N.: 1976a, The Doctrine of Propositions and Terms. Ed. by P. T. Geach and A. J. P. Kenny. University of Massachusetts Press, Amherst, 1976. (A part of Prior's manuscript, 'The Craft of Formal Logic', 1951).

Prior, A. N.: 1976b, Papers in Logic and Ethics. Ed. by P. T. Geach and A. J. P. Kenny. University of Massachusetts Press, Amherst/Duckworth, London, 1976.

Prior, A. N.: 1977, Worlds, Times and Selves. Ed. by Kit Fine, University of Massachusetts Press/Duckworth, London, 1977. (Based on manuscipts by Prior with a preface and a postscript by Kit Fine.)

øhrstrøm, P.; Hasle, P.: 1993, 'A. N. Prior's Rediscovery of Tense Logic'. Erkenntnis, Vol. 39, pp. 23-50.



Per Hasle: Presentation of 'The WWW-site for Prior-studies'.

Centre for Cultural Research, University of Aarhus,

19 May 1998.

First of all, a warm welcome to all of you, and a very special welcome to Dr. Mary Prior. Mary is a researcher and a historian in her own right, but admittedly she is here today as the widow of Arthur Norman Prior, to whose life and thought our web-site is devoted.

So, we are gathered today on the occasion of the release of this Web-site, called 'The WWW-site for Prior-studies'. Since new Web-sites find their way onto the net by the droves each and every day, the mere release of a Web-site may seem a bit of a pretext for doing some celebrating. And in fact, we are good at celebrating here at the Centre for Cultural Research, and if required we do have the expertise for finding retrospectively the appropriate argument for doing so (a cherished technique called 'backwards chaining').

But, even granting all that, it can be said that this Web-site is special in two respects. One has to do with its relation to the life and thought of Arthur Prior, and one with its information theoretic use of the Internet to structure classical humanistic modes of investigation in an entirely new setting.

Let me say just a few words about Prior, who died in 1969, only 54 years old. Prior's great achievement and historical importance was his development of a so-called 'logic of time'. Indeed he laid out the whole foundation of modern temporal logic, as it is also called, almost single-handedly. Now what is this thing a 'logic of time', and why is it important? Well, with the logic of time it is a bit as with relativity theory, you can study it for a lifetime, and since the point about the whole thing is absolutely non-trivial, it is not easy to explain that in


two sentences. So that is just what I will try to do, very brutally: explain what it is, in two sentences - well, maybe paragraphs.

First, the logic of time is logic as concerned with temporal concepts and relations. Past, present, and future are basic parameters of human orientation, a fact also witnessed in language. Thus if I say 'he has become sad', it seems to follow that he is sad NOW (too), but if I say 'he became sad' I suggest nothing about the person's present state of mind. Here you see two very simple sentences with significantly different temporal relations, and you may be ready to believe that - given the time - we could go through sets and sets of very different and much more sophisticated examples. From around 1955 till his death in 1969, Prior developed the conceptual and formal apparatus for describing such various relations.

However, there is an even more important point to be made.

There is a widespread inclination to view logic - and in general, mathematics - as a timeless subject-matter; both in the sense that logic and mathematics should not concern themselves with time, and in the sense that the sentences of mathematics and logic are timelessly true. Two plus two equals four: true today, true yesterday, true forever after; that seems at first glance a rather inevitable way of thinking about it. But in Prior's logic of time, logic is concerned with time, and indeed, logic is itself something temporal. Herein is a breach within the history of philosophy. If this Priorean conception should come to be commonly accepted, that is nothing less than a shift of paradigm within logic and philosophy, comparable to the achievements of Leibniz and George Boole.

And I, for one, do think that that is exactly what is happening - that logic is coming to be viewed as something processual or temporal This is due to a rather surprising combination of forces: namely the impact of information technology on one hand (where the universe is in a sense more temporal than spatial), and on the other hand that substantial shift in modern philosophical approaches, which is in the most diverse


disciplines and orientations marked by an intense focussing on time and change.

I think I promised to give you not much more than two sentences on the logic of time - well, I lied. So let me say just ONE sentence on the Internet-presentation itself. Now you know what to expect, approximately.

The presentation makes available a comprehensive annotation and presentation of Prior's works. Basically, this work started out as a study of the material left by Arthur Prior in the Bodleian Library in Oxford. Some years ago Mary Prior permitted Peter øhrstrøm of the University of Aalborg and myself into the Prior-archive in the Bodleian Library; since then we have hardly been out of it. The archive holds correspondence, papers and drafts for talks, unpublished as well as published material by Arthur Prior, and other items too. Now the piecing together of fragments and letters, published and unpublished manuscripts, the dating of unpublished items and so forth are well-established humanistic research activities. The manner in which various items are thematically and otherwise related to each other can only be recognised on a basis of thorough knowledge - automated indexing would do no good in this case. But on the other hand, hyperlinks prove to be a splendid way of relating items to each other. Thus, if one letter is concerned with the same subject as, say, one unpublished manuscript in the archive and a published paper, these are all linked together directly, using the obvious Internet-techniques. This leads to a very direct system of relations and annotations, based on classical research activities, but organised in a manner that would have been impossible without modern information technology. You can, as it were, travel various themes within Prior's work, and sometimes you can branch off to see how a theme relates to other parts of the authorship. It is like a garden of forking paths - diverging, converging and parallel lines of thought within the work of a great thinker. The impact on how knowledge is organised - indeed, on what knowledge is - is not trivial, but I shall leave that issue aside.


'The WWW-site for Prior-studies' is based on app. 300 pages of text, so it is a rather sizeable thing, too.

In short, it is a piece of work which could not have been organised as it is without modern information technology, and at the same time it could not have been carried out without exercising classical humanistic methods and knowledge. For that reason I think that this presentation is a potentially rewarding case-study also within library science and studies of how the internet can be utilised within the humanities.

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