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Index Paradox

A paradox is a statement that, despite apparently sound reasoning from true premises, leads to an apparently self-contradictory or logically unacceptable conclusion. [1]

96 relations: Abstraction, Adderall, All horses are the same color, Animalia Paradoxa, Antinomy, Aporia, Aristotle, Arrow's impossibility theorem, Attention deficit hyperactivity disorder, Axiom, Barber, Barber paradox, Benzodiazepine, Bhartṛhari, Butterfly effect, Circular definition, Cognitive bias, Contradiction, Critical thinking, Curry's paradox, Dialetheism, Dilemma, Division by zero, Drug, Ethical dilemma, Eubulides, False statement, Faulty generalization, February 29, Formal fallacy, Four-valued logic, Friedrich Nietzsche, G. K. Chesterton, Georg Wilhelm Friedrich Hegel, Gongsun Long, Grandfather paradox, Grelling–Nelson paradox, Half-truth, Heraclitus, Hilbert's paradox of the Grand Hotel, Howler (error), Impossible object, Infinite regress, Irony, Language, Laozi, Liar paradox, List of paradoxes, Logic, M. C. Escher, ..., Mathematical fallacy, Meister Eckhart, Methylphenidate, Mohism, Monty Hall problem, Mu (negative), Oxford University Press, Oxymoron, Paraconsistent logic, Paradox of value, Paradoxes of material implication, Paradoxical reaction, Patrick Hughes (artist), Perspective (graphical), Philosopher, Philosophical Fragments, Plato's beard, Predicate (mathematical logic), Property (philosophy), Revision theory, Russell's paradox, Søren Kierkegaard, School of Names, Schrödinger's cat, Sedative, Self-reference, Self-refuting idea, Set (mathematics), Set theory, Ship of Theseus, Stanford Encyclopedia of Philosophy, Stimulant, Surgery, Syntactic ambiguity, Temporal paradox, The Pirates of Penzance, Thought experiment, Time travel, Twin paradox, Validity, Virtuous circle and vicious circle, Warring States period, Willard Van Orman Quine, Zen, Zeno's paradoxes, Zhuang Zhou. Expand index (46 more) »


Abstraction in its main sense is a conceptual process where general rules and concepts are derived from the usage and classification of specific examples, literal ("real" or "concrete") signifiers, first principles, or other methods.

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Adderall, Adderall XR, and Mydayis are combination drugs containing four salts of the two enantiomers of amphetamine, a central nervous system (CNS) stimulant of the phenethylamine class.

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All horses are the same color

The horse paradox is a falsidical paradox that arises from flawed demonstrations, which purport to use mathematical induction, of the statement All horses are the same color.

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Animalia Paradoxa

Animalia Paradoxa (Latin for "contradictory animals"; cf. paradox) are the mythical, magical or otherwise suspect animals mentioned in editions 1, 2, 3, 4, 5 of Carl Linnaeus's seminal work under the header "Paradoxa".

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Antinomy (Greek ἀντί, antí, "against, in opposition to", and νόμος, nómos, "law") refers to a real or apparent mutual incompatibility of two laws.

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Aporia (impasse, difficulty in passage, lack of resources, puzzlement) denotes in philosophy a philosophical puzzle or state of puzzlement and in rhetoric a rhetorically useful expression of doubt.

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Aristotle (Ἀριστοτέλης Aristotélēs,; 384–322 BC) was an ancient Greek philosopher and scientist born in the city of Stagira, Chalkidiki, in the north of Classical Greece.

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Arrow's impossibility theorem

In social choice theory, Arrow's impossibility theorem, the general possibility theorem or Arrow's paradox is an impossibility theorem stating that when voters have three or more distinct alternatives (options), no ranked voting electoral system can convert the ranked preferences of individuals into a community-wide (complete and transitive) ranking while also meeting a specified set of criteria: unrestricted domain, non-dictatorship, Pareto efficiency and independence of irrelevant alternatives.

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Attention deficit hyperactivity disorder

Attention-deficit hyperactivity disorder (ADHD) is a mental disorder of the neurodevelopmental type.

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An axiom or postulate is a statement that is taken to be true, to serve as a premise or starting point for further reasoning and arguments.

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A barber (from the Latin barba, "beard") is a person whose occupation is mainly to cut, dress, groom, style and shave men’s and boys' hair.

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Barber paradox

The barber paradox is a puzzle derived from Russell's paradox.

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Benzodiazepines (BZD, BZs), sometimes called "benzos", are a class of psychoactive drugs whose core chemical structure is the fusion of a benzene ring and a diazepine ring.

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Bhartṛhari (Devanagari: भर्तृहरि; also romanised as Bhartrihari; fl. c. 5th century CE) is a Sanskrit writer to whom are normally ascribed two influential Sanskrit texts.

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Butterfly effect

In chaos theory, the butterfly effect is the sensitive dependence on initial conditions in which a small change in one state of a deterministic nonlinear system can result in large differences in a later state.

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Circular definition

A circular definition is one that uses the term(s) being defined as a part of the definition or assumes a prior understanding of the term being defined.

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Cognitive bias

A cognitive bias is a systematic pattern of deviation from norm or rationality in judgment.

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In classical logic, a contradiction consists of a logical incompatibility between two or more propositions.

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Critical thinking

Critical thinking is the objective analysis of facts to form a judgment.

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Curry's paradox

Curry's paradox is a paradox in which an arbitrary claim F is proved from the mere existence of a sentence C that says of itself "If C, then F", requiring only a few apparently innocuous logical deduction rules.

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Dialetheism is the view that there are statements which are both true and false.

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A dilemma (δίλημμα "double proposition") is a problem offering two unrelated possibilities, neither of which is unambiguously acceptable or preferable.

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Division by zero

In mathematics, division by zero is division where the divisor (denominator) is zero.

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A drug is any substance (other than food that provides nutritional support) that, when inhaled, injected, smoked, consumed, absorbed via a patch on the skin, or dissolved under the tongue causes a temporary physiological (and often psychological) change in the body.

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Ethical dilemma

An ethical dilemma or ethical paradox is a decision-making problem between two possible moral imperatives, neither of which is unambiguously acceptable or preferable.

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Eubulides (Εὑβουλίδης; fl. 4th century BCE) of Miletus was a philosopher of the Megarian school, and a pupil of Euclid of Megara.

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False statement

A false statement is a statement that is not true.

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Faulty generalization

A faulty generalization is a conclusion about all or many instances of a phenomenon that has been reached on the basis of just one or just a few instances of that phenomenon.

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February 29

February 29, also known as leap day or leap year day, is a date added to most years that are divisible by 4, such as 2008, 2012, 2016, 2020, and 2024.

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Formal fallacy

In philosophy, a formal fallacy, deductive fallacy, logical fallacy or non sequitur (Latin for "it does not follow") is a pattern of reasoning rendered invalid by a flaw in its logical structure that can neatly be expressed in a standard logic system, for example propositional logic.

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Four-valued logic

In logic, a four-valued logic is any logic with four truth values.

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Friedrich Nietzsche

Friedrich Wilhelm Nietzsche (15 October 1844 – 25 August 1900) was a German philosopher, cultural critic, composer, poet, philologist and a Latin and Greek scholar whose work has exerted a profound influence on Western philosophy and modern intellectual history.

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G. K. Chesterton

Gilbert Keith Chesterton, KC*SG (29 May 1874 – 14 June 1936), was an English writer, poet, philosopher, dramatist, journalist, orator, lay theologian, biographer, and literary and art critic.

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Georg Wilhelm Friedrich Hegel

Georg Wilhelm Friedrich Hegel (August 27, 1770 – November 14, 1831) was a German philosopher and the most important figure of German idealism.

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Gongsun Long

Gongsun Long (BC) was a member of the School of Names (Logicians) of ancient Chinese philosophy.

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Grandfather paradox

The grandfather paradox is a paradox of time travel in which inconsistencies emerge through changing the past.

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Grelling–Nelson paradox

The Grelling–Nelson paradox is an antinomy, or a semantic self-referential paradox, concerning the applicability to itself of the word "heterological", meaning "inapplicable to itself." It was formulated in 1908 by Kurt Grelling and Leonard Nelson, and is sometimes mistakenly attributed to the German philosopher and mathematician Hermann Weyl.

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A half-truth is a deceptive statement that includes some element of truth.

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Heraclitus of Ephesus (Hērákleitos ho Ephésios) was a pre-Socratic Greek philosopher, and a native of the city of Ephesus, then part of the Persian Empire.

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Hilbert's paradox of the Grand Hotel

Hilbert's paradox of the Grand Hotel (colloquial: Infinite Hotel Paradox or Hilbert's Hotel) is a thought experiment which illustrates a counterintuitive property of infinite sets.

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Howler (error)

A howler is a glaring blunder, typically an amusing one.

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Impossible object

An impossible object (also known as an impossible figure or an undecidable figure) is a type of optical illusion.

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Infinite regress

An infinite regress in a series of propositions arises if the truth of proposition P1 requires the support of proposition P2, the truth of proposition P2 requires the support of proposition P3,...

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Irony, in its broadest sense, is a rhetorical device, literary technique, or event in which what appears, on the surface, to be the case, differs radically from what is actually the case.

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Language is a system that consists of the development, acquisition, maintenance and use of complex systems of communication, particularly the human ability to do so; and a language is any specific example of such a system.

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Laozi (. Collins English Dictionary.; also Lao-Tzu,. Random House Webster's Unabridged Dictionary.. American Heritage Dictionary of the English Language, Fifth Edition. Houghton Mifflin Company, 2016. or Lao-Tze;, literally "Old Master") was an ancient Chinese philosopher and writer.

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Liar paradox

In philosophy and logic, the classical liar paradox or liar's paradox is the statement of a liar who states that he or she is lying: for instance, declaring that "I am lying" or "everything I say is false".

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List of paradoxes

This is a list of paradoxes, grouped thematically.

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Logic (from the logikḗ), originally meaning "the word" or "what is spoken", but coming to mean "thought" or "reason", is a subject concerned with the most general laws of truth, and is now generally held to consist of the systematic study of the form of valid inference.

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M. C. Escher

Maurits Cornelis Escher (17 June 1898 – 27 March 1972) was a Dutch graphic artist who made mathematically-inspired woodcuts, lithographs, and mezzotints.

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Mathematical fallacy

In mathematics, certain kinds of mistaken proof are often exhibited, and sometimes collected, as illustrations of a concept of mathematical fallacy.

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Meister Eckhart

Eckhart von Hochheim (–), commonly known as Meister Eckhart or Eckehart, was a German theologian, philosopher and mystic, born near Gotha, in the Landgraviate of Thuringia (now central Germany) in the Holy Roman Empire.

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Methylphenidate, sold under various trade names, Ritalin being one of the most commonly known, is a central nervous system (CNS) stimulant of the phenethylamine and piperidine classes that is used in the treatment of attention deficit hyperactivity disorder (ADHD) and narcolepsy.

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Mohism or Moism was an ancient Chinese philosophy of logic, rational thought and science developed by the academic scholars who studied under the ancient Chinese philosopher Mozi (c. 470 BC – c. 391 BC) and embodied in an eponymous book: the Mozi.

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Monty Hall problem

The Monty Hall problem is a brain teaser, in the form of a probability puzzle, loosely based on the American television game show Let's Make a Deal and named after its original host, Monty Hall.

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Mu (negative)

The Japanese and Korean term mu or Chinese wú, meaning "not have; without", is a key word in Buddhism, especially Zen traditions.

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Oxford University Press

Oxford University Press (OUP) is the largest university press in the world, and the second oldest after Cambridge University Press.

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An oxymoron (usual plural oxymorons, more rarely oxymora) is a rhetorical device that uses an ostensible self-contradiction to illustrate a rhetorical point or to reveal a paradox.

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Paraconsistent logic

A paraconsistent logic is a logical system that attempts to deal with contradictions in a discriminating way.

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Paradox of value

The paradox of value (also known as the diamond–water paradox) is the apparent contradiction that, although water is on the whole more useful, in terms of survival, than diamonds, diamonds command a higher price in the market.

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Paradoxes of material implication

The paradoxes of material implication are a group of formulae that are truths of classical logic but are intuitively problematic.

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Paradoxical reaction

A paradoxical reaction or paradoxical effect is an effect of medical treatment, usually a drug, opposite to the effect which would normally be expected.

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Patrick Hughes (artist)

Patrick Hughes (born 20 October 1939) is a British artist working in London.

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Perspective (graphical)

Perspective (from perspicere "to see through") in the graphic arts is an approximate representation, generally on a flat surface (such as paper), of an image as it is seen by the eye.

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A philosopher is someone who practices philosophy, which involves rational inquiry into areas that are outside either theology or science.

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Philosophical Fragments

Philosophical Fragments (Danish title: Philosophiske Smuler eller En Smule Philosophi) is a Christian philosophical work written by Danish philosopher Søren Kierkegaard in 1844.

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Plato's beard

Plato's beard refers to a paradoxical argument dubbed by Willard Van Orman Quine in his 1948 paper On What There Is in which he stated that: This is the old Platonic riddle of nonbeing.

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Predicate (mathematical logic)

In mathematical logic, a predicate is commonly understood to be a Boolean-valued function P: X→, called the predicate on X. However, predicates have many different uses and interpretations in mathematics and logic, and their precise definition, meaning and use will vary from theory to theory.

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Property (philosophy)

In philosophy, mathematics, and logic, a property is a characteristic of an object; a red object is said to have the property of redness.

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Revision theory

Revision theory is a subfield of philosophical logic.

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Russell's paradox

In the foundations of mathematics, Russell's paradox (also known as Russell's antinomy), discovered by Bertrand Russell in 1901, showed that some attempted formalizations of the naïve set theory created by Georg Cantor led to a contradiction.

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Søren Kierkegaard

Søren Aabye Kierkegaard (5 May 1813 – 11 November 1855) was a Danish philosopher, theologian, poet, social critic and religious author who is widely considered to be the first existentialist philosopher.

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School of Names

The Logicians or School of Names was a school of Chinese philosophy that grew out of Mohism during the Warring States period in 479–221 BCE.

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Schrödinger's cat

Schrödinger's cat is a thought experiment, sometimes described as a paradox, devised by Austrian physicist Erwin Schrödinger in 1935.

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A sedative or tranquilliser is a substance that induces sedation by reducing irritability or excitement.

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Self-reference occurs in natural or formal languages when a sentence, idea or formula refers to itself.

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Self-refuting idea

Self-refuting ideas or self-defeating ideas are ideas or statements whose falsehood is a logical consequence of the act or situation of holding them to be true.

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Set (mathematics)

In mathematics, a set is a collection of distinct objects, considered as an object in its own right.

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Set theory

Set theory is a branch of mathematical logic that studies sets, which informally are collections of objects.

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Ship of Theseus

In the metaphysics of Identity, the ship of Theseus (or Theseus's paradox) is a thought experiment that raises the question of whether a ship—standing for an object in general—that has had all of its components replaced remains fundamentally the same object.

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Stanford Encyclopedia of Philosophy

The Stanford Encyclopedia of Philosophy (SEP) combines an online encyclopedia of philosophy with peer-reviewed publication of original papers in philosophy, freely accessible to Internet users.

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Stimulants (also often referred to as psychostimulants or colloquially as uppers) is an overarching term that covers many drugs including those that increase activity of the central nervous system and the body, drugs that are pleasurable and invigorating, or drugs that have sympathomimetic effects.

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Surgery (from the χειρουργική cheirourgikē (composed of χείρ, "hand", and ἔργον, "work"), via chirurgiae, meaning "hand work") is a medical specialty that uses operative manual and instrumental techniques on a patient to investigate or treat a pathological condition such as a disease or injury, to help improve bodily function or appearance or to repair unwanted ruptured areas.

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Syntactic ambiguity

Syntactic ambiguity, also called amphiboly or amphibology, is a situation where a sentence may be interpreted in more than one way due to ambiguous sentence structure.

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Temporal paradox

A temporal paradox, time paradox, or time travel paradox is a paradox, an apparent contradiction, or a logical contradiction that is associated with the idea of time and time travel.

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The Pirates of Penzance

The Pirates of Penzance; or, The Slave of Duty is a comic opera in two acts, with music by Arthur Sullivan and libretto by W. S. Gilbert.

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Thought experiment

A thought experiment (Gedankenexperiment, Gedanken-Experiment or Gedankenerfahrung) considers some hypothesis, theory, or principle for the purpose of thinking through its consequences.

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Time travel

Time travel is the concept of movement between certain points in time, analogous to movement between different points in space by an object or a person, typically using a hypothetical device known as a time machine.

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Twin paradox

In physics, the twin paradox is a thought experiment in special relativity involving identical twins, one of whom makes a journey into space in a high-speed rocket and returns home to find that the twin who remained on Earth has aged more.

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In logic, an argument is valid if and only if it takes a form that makes it impossible for the premises to be true and the conclusion nevertheless to be false.

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Virtuous circle and vicious circle

The terms virtuous circle and vicious circle (also referred to as virtuous cycle and vicious cycle) refer to complex chains of events that reinforce themselves through a feedback loop.

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Warring States period

The Warring States period was an era in ancient Chinese history of warfare, as well as bureaucratic and military reforms and consolidation, following the Spring and Autumn period and concluding with the Qin wars of conquest that saw the annexation of all other contender states, which ultimately led to the Qin state's victory in 221 BC as the first unified Chinese empire known as the Qin dynasty.

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Willard Van Orman Quine

Willard Van Orman Quine (known to intimates as "Van"; June 25, 1908 – December 25, 2000) was an American philosopher and logician in the analytic tradition, recognized as "one of the most influential philosophers of the twentieth century." From 1930 until his death 70 years later, Quine was continually affiliated with Harvard University in one way or another, first as a student, then as a professor of philosophy and a teacher of logic and set theory, and finally as a professor emeritus who published or revised several books in retirement.

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Zen (p; translit) is a school of Mahayana Buddhism that originated in China during the Tang dynasty as Chan Buddhism.

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Zeno's paradoxes

Zeno's paradoxes are a set of philosophical problems generally thought to have been devised by Greek philosopher Zeno of Elea (c. 490–430 BC) to support Parmenides' doctrine that contrary to the evidence of one's senses, the belief in plurality and change is mistaken, and in particular that motion is nothing but an illusion.

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Zhuang Zhou

Zhuang Zhou, often known as Zhuangzi ("Master Zhuang"), was an influential Chinese philosopher who lived around the 4th century BC during the Warring States period, a period corresponding to the summit of Chinese philosophy, the Hundred Schools of Thought.

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Falsidical, Falsidical paradox, Logical paradox, Logical paradoxes, Moral paradox, PARADOX, Paradoces, Paradoxes, Paradoxical, Paradoxically, Paradoxicalness, Paradoxology, Quine's classification of paradoxes, Self-proving, Semantic paradox, Time machine paradox, Veridical paradox.


[1] https://en.wikipedia.org/wiki/Paradox

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