Temporal Logic: From Ancient Ideas to Artificial Intelligence deals with the history of temporal logic as well as the crucial systematic questions within the field. The book studies the rich contributions from ancient and medieval philosophy up to the downfall of temporal logic in the Renaissance. The modern rediscovery of the subject, which is especially due to the work of A. N. Prior, is described, leading into a thorough discussion of the use of temporal logic in computer science and the (...) understanding of natural language. Temporal Logic: From Ancient Ideas to Artificial Intelligence thus interweaves linguistic, philosophical and computational aspects into an informative and inspiring whole. (shrink)

Temporal Logic: From Ancient Ideas to Artificial Intelligence deals with the history of temporal logic as well as the crucial systematic questions within the field. The book studies the rich contributions from ancient and medieval philosophy up to the downfall of temporal logic in the Renaissance. The modern rediscovery of the subject, which is especially due to the work of A. N. Prior, is described, leading into a thorough discussion of the use of temporal logic in computer science and the (...) understanding of natural language. Temporal Logic: From Ancient Ideas to Artificial Intelligence thus interweaves linguistic, philosophical and computational aspects into an informative and inspiring whole. (shrink)

A. N. Prior’s writings should obviously be studied already for historical reasons. His inventions of modern temporal logic and hybrid logic are clearly important events in the history of logic. But the enduring importance of studying his works also rests on his methodological approach, which remains highly relevant also for systematical reasons. In this paper we argue that Prior’s formulation in the 1950s of a tense-logical paradigm for the study of time should be understood in the light of at least (...) three other principles or perspectives which were manifest already in his studies during the 1940s and further developed in the 1950s: his emphasis on the value of interdisciplinary studies, his reflections on formalisation and his view of the role of symbolic logic in conceptual studies and in the philosophy of science. Our investigation into Prior’s basic tenets and principles makes extensive use of Prior’s Nachlass. It is thereby also exemplified how his correspondence and unpublished papers contain important information for a deeper understanding of Prior’s paradigm for the study of time. (shrink)

Arthur Norman Prior (1914-69) was a logician and philosopher from New Zealand who contributed crucially to the development of ‘non-standard’ logics, especially of the modal variety. His greatest achievement was the invention of modern temporal logic, worked out in close connection with modal logic. However, his work in logic had a much broader scope. He was also the founder of hybrid logic, and he made important contributions to deontic logic, modal logic, the theory of quantification, the nature of propositions and (...) the history of logic. In addition, he discussed questions of ethics, free will, and general theology. Prior’s philosophical works comprise about 200 titles. His earliest articles center on philosophical theology and historical studies of Scottish Reformed Theology. This led on to the publication of his first influential work on ethics: Logic and The Basis of Ethics (1949). With the invention of tense-logic in the early 1950s, his focus shifted to investigations into the syntax of tempo-modal logic leading to his seminal Time and Modality (1957), a volume derived from his John Locke Lectures in Oxford in 1956. Furthermore Prior, together with the Irish mathematician and logician C.A. Meredith (1904-76), made important early contributions to the semantics of possible worlds. Prior’s tense-logic provided a strong conceptual framework for problems pertaining to the philosophy of time. In Time and Modality, Prior discussed the philosophical implications of Ruth Barcan’s famous formulae for tense-logic, and in the 1960s he worked on the notion of the present. The most persistent problem running through Prior’s work is his study of the questions surrounding human freedom and divine foreknowledge, and more general philosophical problems emerging from this classical theological question. His thorough analysis of this problem, with the conceptual tools of tense-logic, received a crucial impetus from his correspondence with the young Saul Kripke, when the latter suggested the semantic tool of branching time to Prior. Prior’s development of two solutions based on branching time for the problem of future contingency, the Peircean and the Ockham solution, was most thoroughly developed in Past, Present and Future (1967), the most important work published by Prior. Characteristically for Prior’s methodological approach, the development of these two solutions were at the same time a development of two new systems of tense logic, and vice versa. One of Prior’s significant contributions to logic was his work on world propositions and instant propositions. In the course of developing these notions he also made one of the earliest formulations of hybrid logic. In Papers on Time and Tense (1968), he presented this idea in a more detailed manner in the context of his four grades of tense-logical involvement. (shrink)

Arthur Norman Prior's early theological writings have been relatively neglected for many years. Moreover, to the extent that they have been discussed at all they have been treated mainly as youthful work quite separate from Prior's later work as a philosopher and logician. However, as interest in Prior's achievements has been growing significantly in recent years it has become more important to investigate the development with his overall work. In fact, Prior's putatively "youthful" theological work overlapped his work as a (...) philosopher and logician for many years, as is richly documented by examples discussed in this paper. A particularly important theme is the problem of predestination. This paper presents comprehensive evidence that this theme, which was Prior's most important single preoccupation as a theological writer, was a most important source of inspiration for his development of tense logic. Via questions regarding divine foreknowledge and human free will, predestination was to motivate Prior as a logician to focus on time and tense. Whilst investigating this development, the paper also traces Prior's parallel development from Calvinist Christian believer to a more agnostic position. (shrink)