Semantic paradoxes and theories of truth

By McGee, Vann

The Cretan philosopher Epimenides said that Cretans always lie. Assuming, for the sake of argument, the mendacity of all other statements by Cretans, we get a paradox: if ...

William of Sherwood (c.1200/5–c.1266/75)

By Longeway, John

William of Sherwood, an English logician of the mid-thirteenth century, is most noted for his theories of supposition and syncategorematic terms. In application, these theories enable us to ...

Łukasiewicz, Jan (1878–1956)

By Wolenski, Jan

Before 1918, Łukasiewicz’s interests centred on logic (in the broad sense) and philosophy, and he worked on induction and probability. He also wrote an important historical book on ...

Ramsey, Frank Plumpton (1903–30)

By Mellor, D.H.

Before Ramsey died at the age of 26 he did an extraordinary amount of pioneering work, in economics and mathematics as well as in logic and philosophy. His ...

Logic in the second half of the twentieth century

By Cook, Roy T.; Logan, Shay Allen

By the end of the first half of the twentieth century, logic had become a mature philosophical and mathematical discipline. As happens in mature disciplines, in the second ...

Many-valued logics

By Morgan, Charles G.

Many-valued logics may be distinguished from classical logic on purely semantic grounds. One of the simplifying assumptions on which classical logic is based is the thesis of bivalence, ...

Tarski’s definition of truth

By Gupta, Anil

Alfred Tarski’s definition of truth is unlike any that philosophers have given in their long struggle to understand the concept of truth. Tarski’s definition is more clear and ...

Buridan, John (c.1300–after 1358)

By Zupko, Jack

Unlike most other important philosophers of the scholastic period, John Buridan never entered the theology faculty but spent his entire career as an arts master at the University ...

Logic in China

By Hansen, Chad

Technically, classical China had semantic theory but no logic. Western historians, confusing logic and theory of language, used the term ‘logicians’ to describe those philosophers whom the Chinese ...

Logic, Renaissance

By Ashworth, E.J.

Renaissance logic is often identified with humanist logic, which is in some ways closer to rhetoric than to the study of formal argumentation. This is a mistake, for ...

Russell, Bertrand Arthur William (1872–1970)

By Griffin, Nicholas

Bertrand Russell divided his efforts between philosophy and political advocacy on behalf of a variety of radical causes. He did his most important philosophical work in logic and ...

Stoicism

By Sedley, David

Stoicism is the Greek philosophical system founded by Zeno of Citium c.300 bc and developed by him and his successors into the most influential philosophy of ...

Stoicism

Stoicism is the Greek philosophical system founded by Zeno of Citium c.300 bc and developed by him and his successors into the most influential philosophy of ...

Truth, deflationary theories of

By Liggins, David

Deflationists aim to offer a lucid and metaphysically lightweight account of truth, stripped of obscure or redundant elements. They hold that the theory of truth should be simpler ...

Paraconsistent logic

By Priest, Graham

A logic is paraconsistent if it does not validate the principle that from a pair of contradictory sentences, A and ∼A, everything follows, as most orthodox logics do. ...

Modal operators

By Schweizer, Paul

Modal logic is principally concerned with the alethic modalities of necessity and possibility, although this branch of logic is applied to a wide range of linguistic and conceptual ...

Semantics

By Crimmins, Mark

Semantics is the systematic study of meaning. Current work in this field builds on the work of logicians and linguists as well as of philosophers. Philosophers are interested ...

Kripke, Saul Aaron (1940–)

By Jubien, Michael

Saul Kripke is one of the most important and influential philosophers of the late twentieth century. He is also one of the leading mathematical logicians, having done seminal ...

Paradoxes of set and property

By Moore, Gregory H.

Emerging around 1900, the paradoxes of set and property have greatly influenced logic and generated a vast literature. A distinction due to Ramsey in 1926 separates them into ...

Recursion-theoretic hierarchies

By Hodes, Harold

In mathematics, a hierarchy is a ‘bottom up’ system classifying entities of some particular sort, a system defined inductively, starting with a ‘basic’ class of such entities, with ...