Edward John Lemmon (1 June 1930 – 29 July 1966) was a

British British may refer to: Peoples, culture, and language * British people, nationals or natives of the United Kingdom, British Overseas Territories and Crown Dependencies. * British national identity, the characteristics of British people and culture ...

logician Logic is the study of correct reasoning. It includes both formal and informal logic. Formal logic is the study of deductively valid inferences or logical truths. It examines how conclusions follow from premises based on the structure of arg ...

and

philosopher Philosophy ('love of wisdom' in Ancient Greek) is a systematic study of general and fundamental questions concerning topics like existence, reason, knowledge, Value (ethics and social sciences), value, mind, and language. It is a rational an ...

born in

Sheffield Sheffield is a city in South Yorkshire, England, situated south of Leeds and east of Manchester. The city is the administrative centre of the City of Sheffield. It is historically part of the West Riding of Yorkshire and some of its so ...

England England is a Countries of the United Kingdom, country that is part of the United Kingdom. It is located on the island of Great Britain, of which it covers about 62%, and List of islands of England, more than 100 smaller adjacent islands. It ...

. He is most well known for his work on

modal logic Modal logic is a kind of logic used to represent statements about Modality (natural language), necessity and possibility. In philosophy and related fields it is used as a tool for understanding concepts such as knowledge, obligation, and causality ...

, particularly his joint text with

Dana Scott Dana Stewart Scott (born October 11, 1932) is an American logician who is the emeritus Hillman University Professor of Computer Science, Philosophy, and Mathematical Logic at Carnegie Mellon University; he is now retired and lives in Berkeley, C ...

published posthumously (Lemmon and Scott, 1977).

Biography

Lemmon attended King Edward VII SchoolSchool magazine, 1947
in Sheffield until 1947, before reading Literae humaniores at

Magdalen College, Oxford Magdalen College ( ) is a Colleges of the University of Oxford, constituent college of the University of Oxford. It was founded in 1458 by Bishop of Winchester William of Waynflete. It is one of the wealthiest Oxford colleges, as of 2022, and ...

, as an undergraduate, and was appointed Fellow of

Trinity College, Oxford Trinity College (full name: The College of the Holy and Undivided Trinity in the University of Oxford, of the foundation of Sir Thomas Pope (Knight)) is a Colleges of the University of Oxford, constituent college of the University of Oxford in E ...

, in 1957. In 1963, following a visiting professorship in

Texas Texas ( , ; or ) is the most populous U.S. state, state in the South Central United States, South Central region of the United States. It borders Louisiana to the east, Arkansas to the northeast, Oklahoma to the north, New Mexico to the we ...

, Lemmon emigrated to the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

to lecture at the Claremont Graduate School (now

Claremont Graduate University The Claremont Graduate University (CGU) is a private, all-graduate research university in Claremont, California, United States. Founded in 1925, CGU is a member of the Claremont Colleges consortium which includes five undergraduate and two grad ...

). Lemmon died from

heart failure Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome caused by an impairment in the heart's ability to Cardiac cycle, fill with and pump blood. Although symptoms vary based on which side of the heart is affected, HF ...

while climbing.

Modal logic

John Lemmon became interested in modal logic when Arthur Prior visited

Oxford University The University of Oxford is a collegiate research university in Oxford, England. There is evidence of teaching as early as 1096, making it the oldest university in the English-speaking world and the second-oldest continuously operating u ...

in 1956 to give the

John Locke lectures The John Locke Lectures are a series of annual lectures in philosophy given at the University of Oxford. Named for British philosopher John Locke, the Locke Lectures are the world's most prestigious lectures in philosophy, and are among the world' ...

, later published as his ''Time and Modality'' (Prior 1957). Prior returned for twelve months soon after, to lead a small group including Lemmon,

Peter Geach Peter Thomas Geach (29 March 1916 – 21 December 2013) was a British philosopher who was Professor of Logic at the University of Leeds. His areas of interest were philosophical logic, ethics, history of philosophy, philosophy of religion and ...

and Ivo Thomas (Copeland 2004). John Lemmon became one of the early champions of Prior's distinctive approach to tense logic, and Lemmon's later work on

alethic modality Alethic modality (from Greek ἀλήθεια = truth) is a linguistic modality that indicates modalities of truth, in particular the modalities of logical necessity, contingency, possibility and impossibility. Alethic modality is often associat ...

and applications of modal logic to

ethics Ethics is the philosophy, philosophical study of Morality, moral phenomena. Also called moral philosophy, it investigates Normativity, normative questions about what people ought to do or which behavior is morally right. Its main branches inclu ...

bear the mark of Prior's influence. At this time, Lemmon published a treatment of alethic and

epistemic Epistemology is the branch of philosophy that examines the nature, origin, and limits of knowledge. Also called "the theory of knowledge", it explores different types of knowledge, such as propositional knowledge about facts, practical knowledg ...

modalities that introduced some systems of non-

normal modal logic In logic, a normal modal logic is a set ''L'' of modal formulas such that ''L'' contains: * All propositional tautology (logic), tautologies; * All instances of the Kripke_semantics, Kripke schema: \Box(A\to B)\to(\Box A\to\Box B) and it is closed ...

s that have proven to have had lasting interest, the alethic system S0.5 and the epistemic systems E1–E5 linked to the systems S0.5 and Lewis's systems S2–S5, but which lack the law of necessitation (Lemmon 1957). Lemmon was a pioneer of the modern approach to the

semantics Semantics is the study of linguistic Meaning (philosophy), meaning. It examines what meaning is, how words get their meaning, and how the meaning of a complex expression depends on its parts. Part of this process involves the distinction betwee ...

of modal logic, particularly through his collaboration with

, but also became interested in the rival algebraic semantics of modal logic that follows more closely the kind of semantics found in the work of Tarski and Jónsson.

Works

* 1957. 'New foundations for Lewis modal systems'. ''

Journal of Symbolic Logic The '' Journal of Symbolic Logic'' is a peer-reviewed mathematics journal published quarterly by Association for Symbolic Logic. It was established in 1936 and covers mathematical logic. The journal is indexed by '' Mathematical Reviews'', Zent ...

'' 22:176-186 * With

Michael Dummett Sir Michael Anthony Eardley Dummett (; 27 June 1925 – 27 December 2011) was an English academic described as "among the most significant British philosophers of the last century and a leading campaigner for racial tolerance and equality." H ...

, 1959. 'Modal Logics between S4 and S5'. In ''Zeitschrifl für Mathematische Logik und Grundlagen der Mathematik'', 5:250-264 * 1959, "Is There Only One Correct System of Modal Logic?" ''

Proceedings of the Aristotelian Society The Aristotelian Society for the Systematic Study of Philosophy, more generally known as the Aristotelian Society, is a philosophical society in London. History Aristotelian Society was founded at a meeting on 19 April 1880, at 17 Bloomsbury Squar ...

, Supplementary Volumes'', 33:23-40 * 1962, 'Moral dilemmas'. ''

The Philosophical Review ''The Philosophical Review'' is a quarterly journal of philosophy edited by the faculty of the Sage School of Philosophy at Cornell University. Since September 2006, it is published by Duke University Press. Overview The journal publishes origin ...

'', LXXI * 1966, 'Sentences, Statements and Propositions', in B. Williams and A. Montefiore, eds., ''British Analytical Philosophy'', London: Routledge and Kegan Paul, pp.87-107 * 1967, 'If I Know, Do I Know that I Know?', in A. Stroll, ed., ''Epistemology'', New York: Harper and Rowe, pp54–83. * With

, 1977. ''An introduction to modal logic''. Oxford: Blackwell. *

References

* Ivo Thomas, 1968.
In Memoriam: Edward John Lemmon

Notre Dame Journal of Formal Logic The ''Notre Dame Journal of Formal Logic'' is a quarterly peer-reviewed scientific journal covering the foundations of mathematics and related fields of mathematical logic, as well as philosophy of mathematics. It was established in 1960 and is pub ...

, Vol IX(1). *

Jack Copeland Brian Jack Copeland (born 1950) is Professor of Philosophy at the University of Canterbury, Christchurch, New Zealand, and author of books on the computing pioneer Alan Turing. Education Copeland was educated at the University of Oxford, obt ...

, 2004
Arthur Prior
In the

Stanford Encyclopedia of Philosophy The ''Stanford Encyclopedia of Philosophy'' (''SEP'') is a freely available online philosophy resource published and maintained by Stanford University, encompassing both an online encyclopedia of philosophy and peer-reviewed original publication ...

. {{DEFAULTSORT:Lemmon, John 1930 births 1966 deaths British logicians People educated at King Edward VII School, Sheffield Alumni of Magdalen College, Oxford Place of death missing 20th-century British philosophers