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Czesław Lejewski
Czesław Lejewski (1913 in Minsk – 2001 in Doncaster) was a Polish philosopher and logician, and a member of the Lwow-Warsaw School of Logic. He studied under Jan Łukasiewicz and Karl Popper in the London School of Economics, and W. V. O. Quine. "Logic and Existence" In his paper "Logic and Existence" (1954–55) Lejewski presented a version of free logic A free logic is a logic with fewer existential presuppositions than classical logic. Free logics may allow for terms that do not denote any object. Free logics may also allow models that have an empty domain. A free logic with the latter propert .... He began by presenting the problem of non-referring nouns, and commended Quine for resisting the temptation to solve the problem by saying that non-referring names are meaningless. Quine's solution, however, was that we must first decide whether our name refers before we know how to treat it logically. Lejewski found this unsatisfactory because there should be a formal disti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Logic
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 arguments alone, independent of their topic and content. Informal logic is associated with informal fallacies, critical thinking, and argumentation theory. Informal logic examines arguments expressed in natural language whereas formal logic uses formal language. When used as a countable noun, the term "a logic" refers to a specific logical formal system that articulates a proof system. Logic plays a central role in many fields, such as philosophy, mathematics, computer science, and linguistics. Logic studies arguments, which consist of a set of premises that leads to a conclusion. An example is the argument from the premises "it's Sunday" and "if it's Sunday then I don't have to work" leading to the conclusion "I don't have to wor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jan Łukasiewicz
Jan Łukasiewicz (; 21 December 1878 – 13 February 1956) was a Polish logician and philosopher who is best known for Polish notation and Łukasiewicz logic. His work centred on philosophical logic, mathematical logic and history of logic. He thought innovatively about traditional propositional logic, the principle of non-contradiction and the law of excluded middle, offering one of the earliest systems of many-valued logic. Contemporary research on Aristotelian logic also builds on innovative works by Łukasiewicz, which applied methods from modern logic to the formalization of Aristotle's syllogistic. The Łukasiewicz approach was reinvigorated in the early 1970s in a series of papers by John Corcoran and Timothy Smiley that inform modern translations of '' Prior Analytics'' by Robin Smith in 1989 and Gisela Striker in 2009. Łukasiewicz is regarded as one of the most important historians of logic. Life He was born in Lwów in Austria-Hungary (now Lviv, Ukr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Karl Popper
Sir Karl Raimund Popper (28 July 1902 – 17 September 1994) was an Austrian–British philosopher, academic and social commentator. One of the 20th century's most influential philosophers of science, Popper is known for his rejection of the classical inductivist views on the scientific method in favour of Falsifiability, empirical falsification, and for founding the Department of Philosophy at the London School of Economics. According to Popper, a theory in the empirical sciences can never be proven, but it can be falsified, meaning that it can (and should) be scrutinised with decisive experiments. Popper was opposed to the classical Justification (epistemology), justificationist account of knowledge, which he replaced with "the first non-justificational philosophy of criticism in the history of philosophy", namely critical rationalism. In political discourse, he is known for his vigorous defence of liberal democracy and the principles of social criticism that he believed mad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
London School Of Economics
The London School of Economics and Political Science (LSE), established in 1895, is a public research university in London, England, and a member institution of the University of London. The school specialises in the social sciences. Founded by Fabian Society members Sidney Webb, Beatrice Webb, Graham Wallas and George Bernard Shaw, LSE joined the University of London in 1900 and offered its first degree programmes under the auspices of the university in 1901. LSE began awarding degrees in its own name in 2008, prior to which it awarded degrees of the University of London. It became a university in its own right within the University of London in 2022. LSE is located in the London Borough of Camden and Westminster, Central London, near the boundary between Covent Garden and Holborn. The area is historically known as Clare Market. As of 2023/24, LSE had just under 13,000 students, with the majority being postgraduate students and just under two thirds coming from outsid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jan Woleński
Jan Hertrich-Woleński (also known as Jan Woleński; born 21 September 1940) is a Polish philosopher specializing in the history of the Lwów–Warsaw school of logic and in analytic philosophy. He has spent most of his academic career at the Jagiellonian University in Kraków, where he is currently Professor Emeritus. His main fields of research are logic, epistemology, and the history of philosophy in Poland. Life Jan Woleński was born in Radom, Poland on 21 September 1940. His first interest was law and he began studies at Jagiellonian University in 1958. Soon philosophy drew his attention and by 1963 he was employed in the Department of State and Law as an assistant professor. He looked to analytical jurisprudence in the United Kingdom, and with the guidance of Professor Kazimierz Opalek, in 1968, he produced his thesis. Continuing his ascent, he produced a Habilitation in 1972: ''Problems in the Interpretations of Law''. In 1974 he straddled two positions: the Institute ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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. Each entry is written and maintained by an expert in the field, including professors from many academic institutions worldwide. Authors contributing to the encyclopedia give Stanford University the permission to publish the articles, but retain the copyright to those articles. Approach and history As of August 5, 2022, the ''SEP'' has 1,774 published entries. Apart from its online status, the encyclopedia uses the traditional academic approach of most encyclopedias and academic journals to achieve quality by means of specialist authors selected by an editor or an editorial committee that is competent (although not necessarily considered specialists) in the field covered by the encyclopedia and peer review. The encyclopedia was created i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Free Logic
A free logic is a logic with fewer existential presuppositions than classical logic. Free logics may allow for terms that do not denote any object. Free logics may also allow models that have an empty domain. A free logic with the latter property is an inclusive logic. Explanation In classical logic there are theorems that clearly presuppose that there is something in the domain of discourse. Consider the following classically valid theorems. :1. \forall xA \Rightarrow \exists xA :2. \forall x \forall rA(x) \Rightarrow \forall rA(r) :3. \forall rA(r) \Rightarrow \exists xA(x) A valid scheme in the theory of equality which exhibits the same feature is :4. \forall x(Fx \rightarrow Gx) \land \exists xFx \rightarrow \exists x(Fx \land Gx) Informally, if F is '=y', G is 'is Pegasus', and we substitute 'Pegasus' for y, then (4) appears to allow us to infer from 'everything identical with Pegasus is Pegasus' that something is identical with Pegasus. The problem comes from s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Empty Name
In metaphysics and the philosophy of language, an empty name is a proper name that has no referent. The problem of empty names is the idea that empty names have a meaning when it seems they should not have. The name "Pegasus" is empty; there is nothing to which it refers. Yet, though there is no Pegasus, we know what the sentence "Pegasus has two wings" means. We can even understand the sentence "There is no such thing as Pegasus." But, what can the meaning of a proper name be, except the object to which it refers? Overview There are three broad ways which philosophers have tried to approach this problem. # The meaning of a proper name is not the same as the object (if there is any) it refers to. Hence, though "Pegasus" refers to nothing, it still has a meaning. The German philosopher Gottlob Frege seems to have held a theory of this sort. He says that the sentence Odysseus was set ashore at Ithaca while sound asleep' obviously has a sense. ...the thought xpressed by that sen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Karel Lambert
Karel Lambert (born 1928) is an American philosopher and logician at the University of California, Irvine and the University of Salzburg. He has written extensively on the subject of free logic, a term which he coined. Lambert's law Lambert's law is the major principle in any free definite description theory that says: For all x, x = the y (A) if and only if (A(x/y) & for all y (if A then y = x)). Free logic itself is an adjustment of a given standard predicate logic such as to relieve it of existential assumptions, and so make it a free logic. Taking Bertrand Russell's predicate logic in his ''Principia Mathematica'' as standard, one replaces universal instantiation, \forall x \,\phi x \rightarrow \phi y, with universal specification (\forall x \,\phi x \land E!y \,\phi y) \rightarrow \phi z. Thus universal statements, like "All men are mortal," or "Everything is a unicorn," do not presuppose that there are men or that there is anything. These would be symbolized, with the ap ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arthur Prior
Arthur Norman Prior (4 December 1914 – 6 October 1969), usually cited as A. N. Prior, was a New Zealand–born 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 Prior was born in Masterton, New Zealand, on 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 three weeks after his birth and he was cared for by his father's sister. His father, a medical practitioner in general practice, after war service at Gallipoli and in Francewhere he was awarded the Military Crossremarried in 1920. There were three more children: Elaine, the epidemiologist Ian Prior, and Owen. Arthur Prior grew up in a prominent Methodist household. His two Wesleyan grandfathers, the Reverends Samuel Fowler Prior and Hugh Henwood Teag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Encyclopedia Of Philosophy
An encyclopedia is a reference work or compendium providing summaries of knowledge, either general or special, in a particular field or discipline. Encyclopedias are divided into articles or entries that are arranged alphabetically by article name or by thematic categories, or else are hyperlinked and searchable. Encyclopedia entries are longer and more detailed than those in most dictionaries. Generally speaking, encyclopedia articles focus on ''factual information'' concerning the subject named in the article's title; this is unlike dictionary entries, which focus on linguistic information about words, such as their etymology, meaning, pronunciation, use, and grammatical forms.Béjoint, Henri (2000)''Modern Lexicography'', pp. 30–31. Oxford University Press. Encyclopedias have existed for around 2,000 years and have evolved considerably during that time as regards language (written in a major international or a vernacular language), size (few or many volumes), inte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
