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Self-refuting Idea
A self-refuting idea or self-defeating idea is an idea or statement whose falsehood is a logical consequence of the act or situation of holding them to be true. Many ideas are called self-refuting by their detractors, and such accusations are therefore almost always controversial, with defenders stating that the idea is being misunderstood or that the argument is invalid. For these reasons, none of the ideas below are unambiguously or incontrovertibly self-refuting. These ideas are often used as axioms, which are definitions taken to be true ( tautological assumptions), and cannot be used to test themselves, for doing so would lead to only two consequences: consistency (circular reasoning) or exception (self-contradiction). Variations Directly self-denying statements Directly self-denying statements are characterised by being necessarily (or inherently) false. The Epimenides paradox is a statement of the form "this statement is false". Such statements troubled philosophers, espec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Logical Consequence
Logical consequence (also entailment) is a fundamental concept in logic, which describes the relationship between statements that hold true when one statement logically ''follows from'' one or more statements. A valid logical argument is one in which the conclusion is entailed by the premises, because the conclusion is the consequence of the premises. The philosophical analysis of logical consequence involves the questions: In what sense does a conclusion follow from its premises? and What does it mean for a conclusion to be a consequence of premises?Beall, JC and Restall, Greg, Logical Consequence' The Stanford Encyclopedia of Philosophy (Fall 2009 Edition), Edward N. Zalta (ed.). All of philosophical logic is meant to provide accounts of the nature of logical consequence and the nature of logical truth. Logical consequence is necessary and formal, by way of examples that explain with formal proof and models of interpretation. A sentence is said to be a logical co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Consistency Proof
In classical deductive logic, a consistent theory is one that does not lead to a logical contradiction. The lack of contradiction can be defined in either semantic or syntactic terms. The semantic definition states that a theory is consistent if it has a model, i.e., there exists an interpretation under which all formulas in the theory are true. This is the sense used in traditional Aristotelian logic, although in contemporary mathematical logic the term ''satisfiable'' is used instead. The syntactic definition states a theory T is consistent if there is no formula \varphi such that both \varphi and its negation \lnot\varphi are elements of the set of consequences of T. Let A be a set of closed sentences (informally "axioms") and \langle A\rangle the set of closed sentences provable from A under some (specified, possibly implicitly) formal deductive system. The set of axioms A is consistent when \varphi, \lnot \varphi \in \langle A \rangle for no formula \varphi. If there e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dream Argument
The dream argument is the postulation that the act of dreaming provides preliminary evidence that the senses we trust to distinguish reality from illusion should not be fully trusted, and therefore, any state that is dependent on our senses should at the very least be carefully examined and rigorously tested to determine whether it is in fact reality. Synopsis While dreaming, one does not normally realize one is dreaming. On more rare occasions, the dream may be contained inside another dream with the very act of realizing that one is dreaming, itself, being only a dream that one is not aware of having. This has led philosophers to wonder whether it is possible for one ever to be certain, at any given point in time, that one is not in fact dreaming, or whether indeed it could be possible for one to remain in a perpetual dream state and never experience the reality of wakefulness at all. In Western philosophy this philosophical puzzle was referred to by Plato ( ''Theaetetus'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Evil Demon
The evil demon, also known as Descartes' demon, malicious demon and evil genius, is an epistemological concept that features prominently in Cartesian philosophy. In the first of his 1641 '' Meditations on First Philosophy'', Descartes imagines that an evil demon, of "utmost power and cunning has employed all his energies in order to deceive me." This evil demon is imagined to present a complete illusion of an external world, so that Descartes can say, "I shall think that the sky, the air, the earth, colours, shapes, sounds and all external things are merely the delusions of dreams which he has devised to ensnare my judgement. I shall consider myself as not having hands or eyes, or flesh, or blood or senses, but as falsely believing that I have all these things." Some Cartesian scholars opine that the demon is also omnipotent, and thus capable of altering mathematics and the fundamentals of logic, though omnipotence of the evil demon would be contrary to Descartes' hypothesis, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Skeptical Hypothesis
Philosophical skepticism ( UK spelling: scepticism; from Greek σκέψις ''skepsis'', "inquiry") is a family of philosophical views that question the possibility of knowledge. It differs from other forms of skepticism in that it even rejects very plausible knowledge claims that belong to basic common sense. Philosophical skeptics are often classified into two general categories: Those who deny all possibility of knowledge, and those who advocate for the suspension of judgment due to the inadequacy of evidence. This distinction is modeled after the differences between the Academic skeptics and the Pyrrhonian skeptics in ancient Greek philosophy. In the latter sense, skepticism is understood as a way of life that helps the practitioner achieve inner peace. Some types of philosophical skepticism reject all forms of knowledge while others limit this rejection to certain fields, for example, to knowledge about moral doctrines or about the external world. Some theorists crit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thought Experiment
A thought experiment is a hypothetical situation in which a hypothesis, theory, or principle is laid out for the purpose of thinking through its consequences. History The ancient Greek ''deiknymi'' (), or thought experiment, "was the most ancient pattern of mathematical proof", and existed before Euclidean mathematics, where the emphasis was on the conceptual, rather than on the experimental part of a thought-experiment. Johann Witt-Hansen established that Hans Christian Ørsted was the first to use the German term ' (lit. thought experiment) circa 1812. Ørsted was also the first to use the equivalent term ' in 1820. By 1883 Ernst Mach used the term ' in a different way, to denote exclusively the conduct of a experiment that would be subsequently performed as a by his students. Physical and mental experimentation could then be contrasted: Mach asked his students to provide him with explanations whenever the results from their subsequent, real, physical experiment differed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brain In A Vat
In philosophy, the brain in a vat (BIV) is a scenario used in a variety of thought experiments intended to draw out certain features of human conceptions of knowledge, reality, truth, mind, consciousness, and meaning. It is a modern incarnation of René Descartes's evil demon thought experiment, originated by Gilbert Harman. Found in many science fiction stories, it outlines a scenario in which a mad scientist, machine, or other entity might remove a person's brain from the body, suspend it in a vat of life-sustaining liquid, and connect its neurons by wires to a supercomputer that would provide it with electrical impulses identical to those a brain normally receives. According to such stories, the computer would then be simulating reality (including appropriate responses to the brain's own output) and the "disembodied" brain would continue to have perfectly normal conscious experiences, such as those of a person with an embodied brain, without these being related to obje ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proof By Contradiction
In logic and mathematics, proof by contradiction is a form of proof that establishes the truth or the validity of a proposition, by showing that assuming the proposition to be false leads to a contradiction. Proof by contradiction is also known as indirect proof, proof by assuming the opposite, and ''reductio ad impossibile''. It is an example of the weaker logical refutation '' reductio ad absurdum''. A mathematical proof employing proof by contradiction usually proceeds as follows: #The proposition to be proved is ''P''. #We assume ''P'' to be false, i.e., we assume ''¬P''. #It is then shown that ''¬P'' implies falsehood. This is typically accomplished by deriving two mutually contradictory assertions, ''Q'' and ''¬Q'', and appealing to the Law of noncontradiction. #Since assuming ''P'' to be false leads to a contradiction, it is concluded that ''P'' is in fact true. An important special case is the existence proof by contradiction: in order to demonstrate the existence o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paraconsistent Logics
A paraconsistent logic is an attempt at a logical system to deal with contradictions in a discriminating way. Alternatively, paraconsistent logic is the subfield of logic that is concerned with studying and developing "inconsistency-tolerant" systems of logic which reject the principle of explosion. Inconsistency-tolerant logics have been discussed since at least 1910 (and arguably much earlier, for example in the writings of Aristotle); however, the term ''paraconsistent'' ("beside the consistent") was first coined in 1976, by the Peruvian philosopher Francisco Miró Quesada Cantuarias. The study of paraconsistent logic has been dubbed paraconsistency, which encompasses the school of dialetheism. Definition In classical logic (as well as intuitionistic logic and most other logics), contradictions entail everything. This feature, known as the principle of explosion or ''ex contradictione sequitur quodlibet'' (Latin, "from a contradiction, anything follows") can be expressed form ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Property Is Theft!
"Property is theft!" (french: La propriété, c'est le vol!) is a slogan coined by French anarchist Pierre-Joseph Proudhon in his 1840 book ''What Is Property? or, An Inquiry into the Principle of Right and of Government''. Overview By "property", Proudhon referred to a concept regarding land property that originated in Roman law: the ''sovereign right of property'', the right of the proprietor to do with his property as he pleases, "to use and abuse," so long as in the end he submits to state-sanctioned title. Proudhon contrasts the supposed right of property with the rights (which he considered valid) of liberty, equality, and security. Proudhon was clear that his opposition to property did not extend to exclusive possession of labor-made wealth. In the ''Confessions d'un révolutionnaire'' Proudhon further explained his use of this phrase: Similar phrases Jacques Pierre Brissot had previously written, in his ''Philosophical Inquiries on the Right of Property'' (''R ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pierre-Joseph Proudhon
Pierre-Joseph Proudhon (, , ; 15 January 1809, Besançon – 19 January 1865, Paris) was a French socialist,Landauer, Carl; Landauer, Hilde Stein; Valkenier, Elizabeth Kridl (1979) 959 "The Three Anticapitalistic Movements". ''European Socialism: A History of Ideas and Movements from the Industrial Revolution to Hitler's Seizure of Power''. University of California Press. pp. 59, 63. "In France, post-Utopian socialism begins with Peter Joseph Proudhon. .. roudhonwas the most profound thinker among pre-Marxian socialists."Eatwell, Roger; Wright, Anthony (1999). ''Contemporary Political Ideologies'' (2nd ed.). London: Continuum. p. 82. .Newman, Michael (2005). ''Socialism: A Very Short Introduction''. Oxford University Press. p. 15. .Docherty, James C.; Lamb, Peter, eds. (2006). ''Historical Dictionary of Socialism''. Historical Dictionaries of Religions, Philosophies, and Movements. 73 (2nd ed.). Lanham, Maryland: The Scarecrow Press. p. 284. . See also Lamb, Peter (2015). ''H ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
