A fallacy is a component of an argument which, being demonstrably flawed in its logic or form, renders the argument invalid in whole (except for begging the question fallacy, in which case the argument is valid). Wiktionary (a portmanteau of wiki and dictionary) is a multilingual, Webbased project to create a free content dictionary, available in over 151 languages. ...
Look up argument in Wiktionary, the free dictionary. ...
Logic (from Classical Greek Î»ÏŒÎ³Î¿Ï‚ logos; meaning word, thought, idea, argument, account, reason, or principle) is the study of the principles and criteria of valid inference and demonstration. ...
In logic, the form of an argument is valid precisely if it cannot lead from true premises to a false conclusion. ...
Types of fallacies
In logical arguments, fallacies are either formal or informal. Because the validity of a deductive argument depends on its form, a formal fallacy is a deductive argument that has an invalid form, whereas an informal fallacy is any other invalid mode of reasoning whose flaw is not in the form of the argument. In logic, an argument is a set of statements, consisting of a number of premises, a number of inferences, and a conclusion, which is said to have the following property: if the premises are true, then the conclusion must be true or highly likely to be true. ...
In philosophy, a formal fallacy or a logical fallacy is a pattern of reasoning which is always wrong. ...
In Philosophical logic, an informal fallacy is a pattern of reasoning which is false due to the falsity of one or more of its premises. ...
Beginning with Aristotle, informal fallacies have generally been placed in one of several categories, depending on the source of the fallacy. There are fallacies of relevance, fallacies involving causal reasoning, and fallacies resulting from ambiguities (or equivocations). Most common forms of fallacies are evident in political speeches. For other uses, see Aristotle (disambiguation). ...
Equivocation, also known as amphibology, is classified as both a formal and informal fallacy. ...
Recognizing fallacies in actual arguments may be difficult since arguments are often structured using rhetorical patterns that obscure the logical connections between assertions. Fallacies may also exploit the emotional or intellectual weaknesses of the interlocutor. Having the capability of recognizing logical fallacies in arguments reduces the likelihood of such an occurrence. Rhetoric (from Greek , rhÃªtÃ´r, orator, teacher) is generally understood to be the art or technique of persuasion through the use of oral, visual, or written language; however, this definition of rhetoric has expanded greatly since rhetoric emerged as a field of study in universities. ...
For other uses, see Emotion (disambiguation). ...
An interlocutor (pronounced interlockyouter) describes someone who informally explains the views of a government and also can relay messages back to a government. ...
A different approach to understanding and classifying fallacies is provided by argumentation theory; see for instance the van Eemeren, Grootendorst reference below. In this approach, an argument is regarded as an interactive protocol between individuals which attempts to resolve a disagreement. The protocol is regulated by certain rules of interaction, and violations of these rules are fallacies. Many of the fallacies in the list below are best understood as being fallacies in this sense. Argumentation theory, or argumentation, embraces the arts and sciences of civil debate, dialogue, conversation, and persuasion. ...
In international politics, protocol is the etiquette of diplomacy and affairs of state. ...
Fallacious arguments involve not only formal logic but also causality. Others involve psychological ploys such as use of power relationships between proposer and interlocutor, appeals to patriotism and morality, appeals to ego etc., to establish necessary intermediate (explicit or implicit) premises for an argument. Indeed, fallacies very often lie in unstated assumptions or implied premises in arguments that are not always obvious at first glance. Logic (from ancient Greek λόγος (logos), meaning reason) is the study of arguments. ...
Causality or causation denotes the relationship between one event (called cause) and another event (called effect) which is the consequence (result) of the first. ...
In pragmatics (linguistics), implication is the relationship between two statements where the truth of one suggests the truth of the other, butdistinguishing implication from entailmentdoes not require it. ...
Note that providing a critique of an argument has no relation to the truth of the conclusion. The conclusion could very well be true, while the argument as to why the conclusion is true is not valid. See argument from fallacy. Time Saving Truth from Falsehood and Envy, FranÃ§ois Lemoyne, 1737 For other uses, see Truth (disambiguation). ...
A conclusion is a final proposition, which is arrived at after the consideration of evidence, arguments or premises. ...
The argument from fallacy, also known as argumentum ad logicam or fallacy fallacy, is a logical fallacy which assumes that if an argument is fallacious, its conclusion must be false. ...
Material fallacies The classification of material fallacies widely adopted by modern logicians and based on that of Aristotle, Organon (Sophistici elenchi), is as follows: For other uses, see Aristotle (disambiguation). ...
This article is about Aristotles logical works. ...
On Sophistical Refutations (or De Sophisticis Elenchis) is a text by Aristotle. ...
 Fallacy of Accident (also called destroying the exception or a dicto simpliciter ad dictum secundum quid)makes a generalization that disregards exceptions (e.g., Cutting people is a crime. Surgeons cut people. Therefore, surgeons are criminals.)
 Converse Fallacy of Accident (also called reverse accident, destroying the exception, or a dicto secundum quid ad dictum simpliciter)argues from a special case to a general rule (e.g., If we allow people with glaucoma to use medicinal marijuana then everyone should be allowed to use marijuana.)
 Irrelevant Conclusion (also called Ignoratio Elenchi)diverts attention away from a fact in dispute rather than address it directly. This is sometimes referred to as a "red herring". Subsets include:
 Affirming the Consequentdraws a conclusion from premises that do not support that conclusion by assuming Q implies P on the basis that P implies Q (e.g., If I have the flu, then I have a sore throat. I have a sore throat. Therefore, I have the flu. Other illnesses may cause sore throat.)
 Denying the antecedentdraws a conclusion from premises that do not support that conclusion by assuming Not P implies Not Q on the basis that P implies Q (e.g., If I vote in an American election, I am an American citizen. I do not vote in an American election. Therefore, I am not an American citizen. It is possible for American citizens to choose not to vote.)
 Begging the question (also called Petitio Principii, Circulus in Probandoarguing in a circle, or assuming the answer)demonstrates a conclusion by means of premises that assume that conclusion (e.g., We must institute the death penalty to discourage violent crime. This statement assumes the violent crime rate will fall when the death penalty is imposed.)
 Call to Perfection is committed when one argues to postpone some action or policy until some unlikely event or impossible change is achieved. (example: I'll do it the day that pigs can fly. Since pigs do not fly and will probably never be able to, the action or policy will probably never take place.)
 Fallacy of False Cause or Non Sequitur (Latin for "it does not follow")incorrectly assumes one thing is the cause of another (e.g., Our nation will prevail because God is great.)
 A special case of this fallacy also goes by the Latin term post hoc ergo propter hocthe fallacy of believing that temporal succession implies a causal relation.
 Another special case is given by the Latin term cum hoc ergo propter hoc  the fallacy of believing that happenstance implies causal relation (aka as fallacy of causation versus correlation: assumes that correlation implies causation).
 Fallacy of Many Questions (Plurium Interrogationum)groups more than one question in the form of a single question (e.g., Is it true that you no longer beat your wife? A yes or no answer will still be an admission of guilt to wifebeating.)
The logical fallacy of accident, also called destroying the exception or a dicto simpliciter ad dictum secundum quid, is a deductive fallacy occurring in statistical syllogisms (an argument based on a generalization) when an exception to the generalization is ignored. ...
The logical fallacy of converse accident (also called reverse accident, destroying the exception or a dicto secundum quid ad dictum simpliciter) is a deductive fallacy that can occur in a statistical syllogism when an exception to a generalization is wrongly called for. ...
Ignoratio elenchi (also known as irrelevant conclusion or irrelevant thesis) is the formal fallacy of presenting an argument that may in itself be valid, but doesnt address the issue in question. ...
Ignoratio elenchi (also known as irrelevant conclusion or irrelevant thesis) is the formal fallacy of presenting an argument that may in itself be valid, but doesnt address the issue in question. ...
Look up ad hominem in Wiktionary, the free dictionary. ...
An appeal to the majority (also called argumentum ad populum) is the Americans support the death penalty as an argument for the death penalty is an appeal to the majority and does not logically support the argument. ...
Argumentum ad baculum (Latin: argument to the cudgel or appeal to the stick), also known as appeal to force, is an argument where force, coercion, or the threat of force, is given as a justification for a conclusion. ...
An appeal to authority or argument by authority is a type of argument in logic consisting on basing the truth value of an assertion on the authority, knowledge, expertise, or position of the person asserting it. ...
Affirming the consequent is a logical fallacy in the form of a hypothetical proposition. ...
Denying the antecedent (also known as vacuous implication) is a type of logical fallacy. ...
In logic, begging the question describes a type of logical fallacy, petitio principii, in which the conclusion of an argument is implicitly or explicitly assumed in one of the premises. ...
Non sequitur is Latin for it does not follow. ...
Non sequitur is Latin for it does not follow. ...
For the episode of the television program The West Wing, see Post Hoc, Ergo Propter Hoc (The West Wing). ...
Correlation implies causation, also known as cum hoc ergo propter hoc (Latin for with this, therefore because of this) and false cause, is a logical fallacy by which two events that occur together are claimed to be cause and effect. ...
This article or section does not adequately cite its references or sources. ...
Example James argues:  Cheese is food.
 Food is delicious.
 Therefore, cheese is delicious.
This argument claims to prove that cheese is delicious. This particular argument has the form of a categorical syllogism. Any argument must have premises as well as a conclusion. In this case we need to ask what the premises are—that is, the set of assumptions the proposer of the argument can expect the interlocutor to grant. The first assumption is almost true by definition: cheese is a foodstuff edible by humans. The second assumption is less clear as to its meaning. Since the assertion has no quantifiers of any kind, it could mean any one of the following: Wikipedia does not yet have an article with this exact name. ...
Cheese is a solid food made from the milk of cows, goats, sheep, and other mammals. ...
In language and logic, quantification is a construct that specifies the extent of validity of a predicate, that is the extent to which a predicate holds over a range of things. ...
 All food is delicious.
 Most food is delicious.
 To me, all food is delicious.
 Some food is delicious.
In all but the first interpretation, the above syllogism would then fail to have validated its second premise. James may try to assume that his interlocutor believes that all food is delicious; if the interlocutor grants this then the argument is valid. In this case, the interlocutor is essentially conceding the point to James. However, the interlocutor is more likely to believe that some food is disgusting, such as a frog's liver white chocolate torte with mustard; and in this case James is not much better off than he was before he formulated the argument, since he now has to prove the assertion that cheese is a unique type of universally delicious food, which is a disguised form of the original thesis. From the point of view of the interlocutor, James commits the logical fallacy of begging the question. In logic, begging the question describes a type of logical fallacy, petitio principii, in which the conclusion of an argument is implicitly or explicitly assumed in one of the premises. ...
Verbal fallacies Verbal fallacies are those in which a conclusion is obtained by improper or ambiguous use of words. They are generally classified as follows.  Equivocation consists in employing the same word in two or more senses, e.g. in a syllogism, the middle term being used in one sense in the major and another in the minor premise, so that in fact there are four not three terms ("All heavy things have a great mass; This is heavy fog; therefore this fog has a great mass").
 Connotation fallacies occur when a dysphemistic word is substituted for the speaker's actual quote and used to discredit the argument. It is a form of attribution fallacy.
 Amphibology is the result of ambiguity of grammatical structure, e.g. of the position of the adverb "only" in careless writers ("He only said that," in which sentence, the adverb has been intended to qualify any one of the other three words).
 Fallacy of Composition "From Each to All". Arguing from some property of constituent parts, to the conclusion that the composite item has that property e.g. "all the band members (constituent parts) are highly skilled, therefore the band (composite item) is highly skilled". This can be acceptable with certain arguments such as spatio arguments e.g. "all the parts of the car are in the garage, therefore the car is in the garage"
 Division, the converse of the preceding, arguing from a property of the whole, to each constituent part e.g. "the university (the whole) is 700 years old, therefore, all the staff (each part) are 700 years old".
 Proof by verbosity, sometimes colloquially referred to as argumentum verbosium  a rhetorical technique that tries to persuade by overwhelming those considering an argument with such a volume of material that the argument sounds plausible, superficially appears to be wellresearched, and it is so laborious to untangle and check supporting facts that the argument might be allowed to slide by unchallenged.
 Accent, which occurs only in speaking and consists of emphasizing the wrong word in a sentence. e.g., "He is a fairly good pianist," according to the emphasis on the words, may imply praise of a beginner's progress, or an expert's deprecation of a popular hero, or it may imply that the person in question is a deplorable pianist.^{[citation needed]}
 Figure of Speech, the confusion between the metaphorical and ordinary uses of a word or phrase.
 Fallacy of Misplaced Concretion, identified by Whitehead in his discussion of metaphysics, this refers to the reification of concepts which exist only in discourse.
Equivocation, also known as amphibology, is classified as both a formal and informal fallacy. ...
A syllogism (Greek: â€” conclusion, inference), usually the categorical syllogism, is a kind of logical argument in which one proposition (the conclusion) is inferred from two others (the premises) of a certain form. ...
Amphibology or amphiboly (from the Greek amphibolia) is, in logic, a verbal fallacy arising from ambiguity in the grammatical structure of a sentence. ...
A fallacy of composition arises when one infers that something is true of the whole from the fact that it is true of some part of the whole (or even of every proper part). ...
A fallacy of division occurs when someone reasons logically that something that is true of a thing must also be true of its constituents. ...
Proof by verbosity is a term used to describe an excessively verbose mathematical proof that may or may not actually prove the result. ...
Example 1 Barbara argues:  Andre is a good tennis player.
 Therefore, Andre is 'good', that is to say a morally good person.
Here the problem is that the word good has different meanings, which is to say that it is an ambiguous word. In the premise, Barbara says that Andre is good at some particular activity, in this case tennis. In the conclusion, she says that Andre is a morally good person. These are clearly two different senses of the word "good". The premise might be true but the conclusion can still be false: Andre might be the best tennis player in the world but a rotten person morally. However, it is not legitimate to infer he is a bad person on the ground there has been a fallacious argument on the part of Barbara. Nothing concerning Andre's moral qualities is to be inferred from the premise. Appropriately, since it plays on an ambiguity, this sort of fallacy is called the fallacy of equivocation, that is, equating two incompatible terms or claims. Good. ...
Look up ambiguity in Wiktionary, the free dictionary. ...
Equivocation, also known as amphibology, is classified as both a formal and informal fallacy. ...
Example 2 Jason argues:  Nothing is better than eternal happiness.
 Eating a hamburger is better than nothing.
 Therefore, eating a hamburger is better than eternal happiness.
This argument has the appearance of an inference that applies transitivity of the twoplaced relation is better than, which in this critique we grant is a valid property. The argument is an example of syntactic ambiguity. In fact, the first premise semantically does not predicate an attribute of the subject, as would for instance the assertion In mathematics, a binary relation R over a set X is transitive if it holds for all a, b, and c in X, that if a is related to b and b is related to c, then a is related to c. ...
 A potato is better than eternal happiness.
In fact it is semantically equivalent to the following universal quantification: In predicate logic, universal quantification is an attempt to formalize the notion that something (a logical predicate) is true for everything, or every relevant thing. ...
 Everything fails to be better than eternal happiness.
So instantiating this fact with eating a hamburger, it logically follows that  Eating a hamburger fails to be better than eternal happiness.
Note that the premise A hamburger is better than nothing does not provide anything to this argument. This fact really means something such as  Eating a hamburger is better than eating nothing at all.
Thus this is a fallacy of composition. A fallacy of composition arises when one infers that something is true of the whole from the fact that it is true of some part of the whole (or even of every proper part). ...
These sort of fallacies are firmly tied to English language and how the words are used in ambiguous ways in several expressions. The phrase "nothing is better than X" actually means "Such a thing that would be better than X does not exist". If the arguments mentioned in this article were to be translated to other languages, they would suddenly make no sense at all since the word "nothing" would be translated differently in different sentences.
Logical fallacy The standard Aristotelian logical fallacies are: Other logical fallacies include: The fallacy of four terms (Latin: quaternio terminorum) is a logical fallacy that occurs when a threepart syllogism has four terms. ...
The fallacy of the undistributed middle is a logical fallacy that is committed when the middle term in a categorical syllogism isnt distributed. ...
This article may be too technical for most readers to understand. ...
Illicit minor is a logical fallacy committed in a categorical syllogism that is invalid because its minor term is undistributed in the minor premise but distributed in the conclusion. ...
Affirmative conclusion from a negative premise is a logical fallacy that is committed when a categorical syllogism has a positive conclusion, but one or two negative premises. ...
In philosophy, the term logical fallacy properly refers to a formal fallacy : a flaw in the structure of a deductive argument which renders the argument invalid. In logic, begging the question describes a type of logical fallacy, petitio principii, in which the conclusion of an argument is implicitly or explicitly assumed in one of the premises. ...
For other uses, see Philosophy (disambiguation). ...
Deductive reasoning is reasoning whose conclusions are intended to necessarily follow from its premises. ...
In logic, an argument is a set of statements, consisting of a number of premises, a number of inferences, and a conclusion, which is said to have the following property: if the premises are true, then the conclusion must be true or highly likely to be true. ...
In logic, the form of an argument is valid precisely if it cannot lead from true premises to a false conclusion. ...
However, it is often used more generally in informal discourse to mean an argument which is problematic for any reason, and thus encompasses informal fallacies as well as formal fallacies. – valid but unsound claims or bad nondeductive argumentation – . // Info Unsound is the second album by industrial metal band Shardhead. ...
The presence of a formal fallacy in a deductive argument does not imply anything about the argument's premises or its conclusion (see fallacy fallacy). Both may actually be true, or even more probable as a result of the argument (e.g. appeal to authority), but the deductive argument is still invalid because the conclusion does not follow from the premises in the manner described. By extension, an argument can contain a formal fallacy even if the argument is not a deductive one; for instance an inductive argument that incorrectly applies principles of probability or causality can be said to commit a formal fallacy. The argument from fallacy, also known as argumentum ad logicam or fallacy fallacy, is a logical fallacy which assumes that because an argument is fallacious then its conclusion must be false. ...
An appeal to authority or argument by authority is a type of argument in logic consisting on basing the truth value of an assertion on the authority, knowledge, expertise, or position of the person asserting it. ...
Probability is the likelihood or chance that something is the case or will happen. ...
Causality or causation denotes the relationship between one event (called cause) and another event (called effect) which is the consequence (result) of the first. ...
Example
An image depicting a common logical fallacy. In the strictest sense, a logical fallacy is the incorrect application of a valid logical principle or an application of a nonexistent principle: Image File history File links No higher resolution available. ...
Image File history File links No higher resolution available. ...
 Most Rimnars are Jornars.
 Most Jornars are Dimnars.
 Therefore, most Rimnars are Dimnars.
This is fallacious. And so is this:  The average family has 2.5 children.
 The Smiths are a very average family.
 Therefore, the Smiths must have 2 or 3 children.
Indeed, there is no logical principle that states:  For some x, P(x).
 For some x, Q(x).
 Therefore for some x, P(x) and Q(x).
An easy way to show the above inference is invalid is by using Venn diagrams. In logical parlance, the inference is invalid, since under at least one interpretation of the predicates it is not validity preserving. A Venn diagram of sets A, B, and C Venn diagrams (or set diagrams) are illustrations used in the branch of mathematics known as set theory. ...
Other systems of classification Of other classifications of fallacies in general the most famous are those of Francis Bacon and J. S. Mill. Bacon (Novum Organum, Aph. 33, 38 sqq.) divided fallacies into four Idola (Idols, i.e. False Appearances), which summarize the various kinds of mistakes to which the human intellect is prone. With these should be compared the Offendicula of Roger Bacon, contained in the Opus maius, pt. i. J. S. Mill discussed the subject in book v. of his Logic, and Jeremy Bentham's Book of Fallacies (1824) contains valuable remarks. See Rd. Whateley's Logic, bk. v.; A. de Morgan, Formal Logic (1847) ; A. Sidgwick, Fallacies (1883) and other textbooks. Sir Francis Bacon Francis Bacon, 1st Viscount St Albans, KC (22 January 1561 â€“ 9 April 1626) was an English astrologer, philosopher, statesman, spy, freemason and essayist. ...
John Stuart Mill (20 May 1806 â€“ 8 May 1873), British philosopher, political economist, civil servant and Member of Parliament, was an influential liberal thinker of the 19th century. ...
The Novum Organum is a philosophical work by Francis Bacon published in 1620. ...
Fallacies in the media and politics  This section does not cite any references or sources. (June 2008) Please help improve this section by adding citations to reliable sources. Unverifiable material may be challenged and removed.  "Either you're for me, or against me" unknown but common fallacy (False dilemma). Fallacies are used frequently by pundits in the media and politics. When one politician says to another, "You don't have the moral authority to say X", this could be an example of the argumentum ad hominem or personal attack fallacy; that is, attempting to disprove X, not by addressing validity of X but by attacking the person who asserted X. Arguably, the politician is not even attempting to make an argument against X, but is instead offering a moral rebuke against the interlocutor. For instance, if X is the assertion: This article or section does not cite its references or sources. ...
For other uses, see Politics (disambiguation). ...
Look up ad hominem in Wiktionary, the free dictionary. ...
// Dont do it Shortcut: WP:NPA Do not make personal attacks anywhere in Wikipedia. ...
 The military uniform is a symbol of national strength and honor.
Then ostensibly, the politician is not trying to prove the contrary assertion. If this is the case, then there is no logically fallacious argument, but merely a personal opinion about moral worth. Thus identifying logical fallacies may be difficult and dependent upon context. In the opposite direction is the fallacy of argument from authority. A classic example is the ipse dixit—"He himself said it" argument—used throughout the Middle Ages in reference to Aristotle. A modern instance is "celebrity spokespersons" in advertisements: a product is good and you should buy/use/support it because your favorite celebrity endorses it. An appeal to authority or argument by authority is a type of argument in logic consisting on basing the truth value of an assertion on the authority, knowledge, expertise, or position of the person asserting it. ...
Ipsedixitism is the pejorative term for an unsupported rhetorical assertion; the term in Logic for a missing argument. ...
The Middle Ages formed the middle period in a traditional schematic division of European history into three ages: the classical civilization of Antiquity, the Middle Ages, and modern times, beginning with the Renaissance. ...
For other uses, see Aristotle (disambiguation). ...
An appeal to authority is always a logical fallacy, though it can be an appropriate form of rational argument if, for example, it is an appeal to expert testimony^{[citation needed]} . In this case, the expert witness must be recognized as such and all parties must agree that the testimony is appropriate to the circumstances. This form of argument is common in legal situations. Rationality as a term is related to the idea of reason, a word which following Websters may be derived as much from older terms referring to thinking itself as from giving an account or an explanation. ...
An expert witness is a witness, who by virtue of education, or profession, or experience, is believed to have special knowledge of his subject beyond that of the average person, sufficient that others may officially (and legally) rely his opinion. ...
By definition, arguments with logical fallacies are invalid, but they can often be (re)written in such a way that they fit a valid argument form. The challenge to the interlocutor is, of course, to discover the false premise, i.e. the premise that makes the argument unsound. In logic, the form of an argument is valid precisely if it cannot lead from true premises to a false conclusion. ...
In logic, the argument form or test form of an argument results from replacing the different words, or sentences, that make up the argument with letters, along the lines of algebra; the letters represent logical variables. ...
A false premise is an incorrect proposition that forms the basis of a logical syllogism. ...
(This article discusses the soundess notion of informal logic. ...
See also This is a list of fallacies. ...
Attacking Faulty Reasoning is a textbook on logical fallacies by T. Edward Damer that has been used for many years in a number of college courses on logic, critical thinking, argumentation, and philosophy. ...
Time Saving Truth from Falsehood and Envy, FranÃ§ois Lemoyne, 1737 For other uses, see Truth (disambiguation). ...
This article does not cite any references or sources. ...
References  Aristotle, On Sophistical Refutations, De Sophistici Elenchi.
 William of Ockham, Summa of Logic (ca. 1323) Part III.4.
 John Buridan, Summulae de dialectica Book VII.
 Francis Bacon, the doctrine of the idols in Novum Organum Scientiarum, Aphorisms concerning The Interpretation of Nature and the Kingdom of Man, XXIIIff.
 The Art of Controversy  Die Kunst, Recht zu behalten  The Art Of Controversy (bilingual), by Arthur Schopenhauer (also known as "Schopenhauers 38 stratagems")
 John Stuart Mill, A System of Logic  Raciocinative and Inductive. Book 5, Chapter 7, Fallacies of Confusion.
 C. L. Hamblin, Fallacies. Methuen London, 1970.
 Fearnside, W. Ward and William B. Holther, Fallacy: The Counterfeit of Argument, 1959.
 Vincent F. Hendricks, Thought 2 Talk: A Crash Course in Reflection and Expression, New York: Automatic Press / VIP, 2005, ISBN 8799101378
 D. H. Fischer, Historians' Fallacies: Toward a Logic of Historical Thought, Harper Torchbooks, 1970.
 Douglas N. Walton, Informal logic: A handbook for critical argumentation. Cambridge University Press, 1989.
 F. H. van Eemeren and R. Grootendorst, Argumentation, Communication and Fallacies: A PragmaDialectical Perspective, Lawrence Erlbaum and Associates, 1992.
 Warburton Nigel, Thinking from A to Z, Routledge 1998.
 T. Edward Damer. Attacking Faulty Reasoning, 5th Edition, Wadsworth, 2005. ISBN 0534605168
 Sagan, Carl, "The DemonHaunted World: Science As a Candle in the Dark". Ballantine Books, March 1997 ISBN 0345409469, 480 pgs. 1996 hardback edition: Random House, ISBN 039453512X, xv+457 pages plus addenda insert (some printings). Ch.12.
For other uses, see Aristotle (disambiguation). ...
William of Ockham (also Occam or any of several other spellings, IPA: ) (c. ...
Arthur Schopenhauer (February 22, 1788 â€“ September 21, 1860) was a German philosopher best known for his work The World as Will and Representation. ...
Year 1970 (MCMLXX) was a common year starting on Thursday (link shows full calendar) of the Gregorian calendar. ...
Vincent F. Hendricks is a philosopher and logician. ...
Year 1989 (MCMLXXXIX) was a common year starting on Sunday (link displays 1989 Gregorian calendar). ...
Year 1992 (MCMXCII) was a leap year starting on Wednesday (link will display full 1992 Gregorian calendar). ...
Year 1998 (MCMXCVIII) was a common year starting on Thursday (link will display full 1998 Gregorian calendar). ...
Attacking Faulty Reasoning is a textbook on logical fallacies by T. Edward Damer that has been used for many years in a number of college courses on logic, critical thinking, argumentation, and philosophy. ...
Carl Edward Sagan (November 9, 1934 â€“ December 20, 1996) was an American astronomer and astrochemist and a highly successful popularizer of astronomy, astrophysics, and other natural sciences. ...
The DemonHaunted World: Science as a Candle in the Dark is a 1997 book by Carl Sagan. ...
Ballantine Books, founded in 1952 by Ian Ballantine, is a major book publisher and is currently owned by Random House. ...
// Random House is a publishing house based in New York City. ...
External links
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Logic (from Classical Greek Î»ÏŒÎ³Î¿Ï‚ logos; meaning word, thought, idea, argument, account, reason, or principle) is the study of the principles and criteria of valid inference and demonstration. ...
The history of logic documents the development of logic as it occurs in various rival cultures and traditions in history. ...
In Islamic philosophy, logic played an important role. ...
For other uses, see Reason (disambiguation). ...
Philosophical logic is the application of formal logical techniques to problems that concern philosophers. ...
Philosophy of logic is the branch of philosophy that is concerned with the nature and justification of systems of logic. ...
Mathematical logic is a major area of mathematics, which grew out of symbolic logic. ...
The metalogic of a system of logic is the formal proof supporting its soundness. ...
To meet Wikipedias quality standards, this article or section may require cleanup. ...
Reasoning is the mental (cognitive) process of looking for reasons to support beliefs, conclusions, actions or feelings. ...
Deductive reasoning is reasoning whose conclusions are intended to necessarily follow from its premises. ...
Aristotle appears first to establish the mental behaviour of induction as a category of reasoning. ...
Abduction, or inference to the best explanation, is a method of reasoning in which one chooses the hypothesis that would, if true, best explain the relevant evidence. ...
Informal logic is the study of arguments as presented in ordinary language, as contrasted with the presentations of arguments in an artificial (technical) or formal language (see formal logic). ...
This article is about the word proposition as it is used in logic, philosophy, and linguistics. ...
Inference is the act or process of deriving a conclusion based solely on what one already knows. ...
Look up argument in Wiktionary, the free dictionary. ...
In logic, the form of an argument is valid precisely if it cannot lead from true premises to a false conclusion. ...
An argument is cogent if and only if the truth of the arguments premises would render the truth of the conclusion probable (i. ...
Traditional logic, also known as term logic, is a loose term for the logical tradition that originated with Aristotle and survived broadly unchanged until the advent of modern predicate logic in the late nineteenth century. ...
are you kiddin ? i was lookin for it for hours ...
A syllogism (Greek: â€” conclusion, inference), usually the categorical syllogism, is a kind of logical argument in which one proposition (the conclusion) is inferred from two others (the premises) of a certain form. ...
Argumentation theory, or argumentation, embraces the arts and sciences of civil debate, dialogue, conversation, and persuasion. ...
Philosophy of logic is the branch of philosophy that is concerned with the nature and justification of systems of logic. ...
Platonic realism is a philosophical term usually used to refer to the idea of realism regarding the existence of universals after the Greek philosopher Plato who lived between c. ...
Logical atomism is a philosophical belief that originated in the early 20th century with the development of analytic philosophy. ...
Logicism is one of the schools of thought in the philosophy of mathematics, putting forth the theory that mathematics is an extension of logic and therefore some or all mathematics is reducible to logic. ...
In philosophy, nominalism is the theory that abstract terms, general terms, or universals do not represent objective real existents, but are merely names, words, or vocal utterances (flatus vocis). ...
Fictionalism is a doctrine in philosophy that suggests that statements of a certain sort should not be taken to be literally true, but merely a useful fiction. ...
Contemporary philosophical realism, also referred to as metaphysical realism, is the belief in a reality that is completely ontologically independent of our conceptual schemes, linguistic practices, beliefs, etc. ...
In the philosophy of mathematics, intuitionism, or neointuitionism (opposed to preintuitionism), is an approach to mathematics as the constructive mental activity of humans. ...
In the philosophy of mathematics, constructivism asserts that it is necessary to find (or construct) a mathematical object to prove that it exists. ...
In the philosophy of mathematics, finitism is an extreme form of constructivism, according to which a mathematical object does not exist unless it can be constructed from natural numbers in a finite number of steps. ...
Mathematical logic is a major area of mathematics, which grew out of symbolic logic. ...
In mathematics, logic, and computer science, a formal language is a language that is defined by precise mathematical or machine processable formulas. ...
In computer science and linguistics, a formal grammar, or sometimes simply grammar, is a precise description of a formal language â€” that is, of a set of strings. ...
In logic and mathematics, a formal system consists of two components, a formal language plus a set of inference rules or transformation rules. ...
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In theoretical computer science formal semantics is the field concerned with the rigorous mathematical study of the meaning of programming languages and models of computation. ...
In mathematical logic, a formula is a formal syntactic object that expresses a proposition. ...
In logic, WFF is an abbreviation for wellformed formula. ...
In mathematics, a set can be thought of as any collection of distinct objects considered as a whole. ...
In mathematics, an element (also called a member) is an object contained in a set (or more generally a class). ...
In set theory and its applications throughout mathematics, a class is a collection of sets (or sometimes other mathematical objects) that can be unambiguously defined by a property that all its members share. ...
This article is about a logical statement. ...
In logic, especially in mathematical logic, a rule of inference is a scheme for constructing valid inferences. ...
In mathematics, the concept of a relation is a generalization of 2place relations, such as the relation of equality, denoted by the sign = in a statement like 5 + 7 = 12, or the relation of order, denoted by the sign < in a statement like 5 < 12. Relations that involve two...
A mathematical picture paints a thousand words: the Pythagorean theorem. ...
Logical consequence is the relation that holds between a set of sentences and a sentence when the latter follows from the former. ...
Look up Consistency in Wiktionary, the free dictionary. ...
(This article discusses the soundess notion of informal logic. ...
Look up completeness in Wiktionary, the free dictionary. ...
A logical system or theory is decidable if the set of all wellformed formulas valid in the system is decidable. ...
3SAT redirects here. ...
Set theory is the mathematical theory of sets, which represent collections of abstract objects. ...
In mathematics, an axiomatic system is any set of axioms from which some or all axioms can be used in conjunction to logically derive theorems. ...
Proof theory is a branch of mathematical logic that represents proofs as formal mathematical objects, facilitating their analysis by mathematical techniques. ...
In mathematics, model theory is the study of the representation of mathematical concepts in terms of set theory, or the study of the structures that underlie mathematical systems. ...
Recursion theory, or computability theory, is a branch of mathematical logic dealing with generalizations of the notion of computable function, and with related notions such as Turing degrees and effective descriptive set theory. ...
At the broadest level, type theory is the branch of mathematics and logic that first creates a hierarchy of types, then assigns each mathematical (and possibly other) entity to a type. ...
Syntax in logic is a systematic statement of the rules governing the properly formed formulas (WFFs) of a logical system. ...
Propositional logic or sentential logic is the logic of propositions, sentences, or clauses. ...
A Boolean function describes how to determine a Boolean value output based on some logical calculation from Boolean inputs. ...
In logic, the monadic predicate calculus is the fragment of predicate calculus in which all predicate letters are monadic (that is, they take only one argument), and there are no function letters. ...
In logic and mathematics, a propositional calculus (or a sentential calculus) is a formal system in which formulas representing propositions can be formed by combining atomic propositions using logical connectives, and a system of formal proof rules allows to establish that certain formulas are theorems of the formal system. ...
In logic, a logical connective is a syntactic operation on sentences, or the symbol for such an operation, that corresponds to a logical operation on the logical values of those sentences. ...
Truth tables are a type of mathematical table used in logic to determine whether an expression is true or whether an argument is valid. ...
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Firstorder logic (FOL) is a formal deductive system used by mathematicians, philosophers, linguists, and computer scientists. ...
In language and logic, quantification is a construct that specifies the extent of validity of a predicate, that is the extent to which a predicate holds over a range of things. ...
In mathematical logic, secondorder logic is an extension of firstorder logic, which itself is an extension of propositional logic. ...
System T redirects here. ...
Deontic logic is the field of logic that is concerned with obligation, permission, and related concepts. ...
Michaels the greatest boyfriend in the whole wide world, and Id love to call him in a phonebooth sometime. ...
In logic, the term temporal logic is used to describe any system of rules and symbolism for representing, and reasoning about, propositions qualified in terms of time. ...
doxastic logic is a modal logic that is concerned with reasoning about beliefs. ...
Classical logic identifies a class of formal logics that have been most intensively studied and most widely used. ...
Introduced by Giorgi Japaridze in 2003, Computability logic is a research programme and mathematical framework for redeveloping logic as a systematic formal theory of computability, as opposed to classical logic which is a formal theory of truth. ...
For the Super Furry Animals album, see Fuzzy Logic (album). ...
In mathematical logic, linear logic is a type of substructural logic that denies the structural rules of weakening and contraction. ...
Relevance logic, also called relevant logic, is any of a family of nonclassical substructural logics that impose certain restrictions on implication. ...
A nonmonotonic logic is a formal logic whose consequence relation is not monotonic. ...
A paraconsistent logic is a logical system that attempts to deal nontrivially with contradictions. ...
Dialetheism is a paraconsistent logic typified by its tolerance of at least some contradictions. ...
Intuitionistic logic, or constructivist logic, is the logic used in mathematical intuitionism and other forms of mathematical constructivism. ...
Look up paradox in Wiktionary, the free dictionary. ...
Antinomy (Greek anti, against, plus nomos, law) is a term used in logic and epistemology, which, loosely, means a paradox or unresolvable contradiction. ...
Is logic empirical? is the title of two articles that discuss the idea that the algebraic properties of logic may, or should, be empirically determined; in particular, they deal with the question of whether empirical facts about quantum phenomena may provide grounds for revising classical logic as a consistent logical...
Al Farabi (870950) was born of a Turkish family and educated by a Christian physician in Baghdad, and was himself later considered a teacher on par with Aristotle. ...
Abu HÄmed Mohammad ibn Mohammad alGhazzÄlÄ« (10581111) (Persian: ), known as Algazel to the western medieval world, born and died in Tus, in the Khorasan province of Persia (modern day Iran). ...
For the Christian theologian, see Abd alMasih ibn Ishaq alKindi. ...
Fakhr alDin alRazi (1149â€“1209) was a wellknown Persian theologian and philosopher from Ray. ...
For other uses, see Aristotle (disambiguation). ...
Ibn Rushd, known as Averroes (1126 â€“ December 10, 1198), was an AndalusianArab philosopher and physician, a master of philosophy and Islamic law, mathematics, and medicine. ...
For the lunar crater, see Avicenna (crater). ...
Not to be confused with George Boolos. ...
Georg Ferdinand Ludwig Philipp Cantor (March 3, 1845[1] â€“ January 6, 1918) was a German mathematician. ...
Rudolf Carnap (May 18, 1891, Ronsdorf, Germany â€“ September 14, 1970, Santa Monica, California) was an influential philosopher who was active in central Europe before 1935 and in the United States thereafter. ...
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Dharmakirti (circa 7th century), was an Indian scholar and one of the Buddhist founders of Indian philosophical logic. ...
DignÄga (5th century AD), was an Indian scholar and one of the Buddhist founders of Indian philosophical logic. ...
Friedrich Ludwig Gottlob Frege (8 November 1848, Wismar â€“ 26 July 1925, IPA: ) was a German mathematician who became a logician and philosopher. ...
Gerhard Karl Erich Gentzen (November 24, 1909 â€“ August 4, 1945) was a German mathematician and logician. ...
Kanada (also transliterated as Kanad and in other ways; Sanskrit à¤•à¤£à¤¾à¤¦) was a Hindu sage who founded the philosophical school of Vaisheshika. ...
Kurt GÃ¶del (IPA: ) (April 28, 1906 BrÃ¼nn, AustriaHungary (now Brno, Czech Republic) â€“ January 14, 1978 Princeton, New Jersey) was an Austrian American mathematician and philosopher. ...
The NyÄya SÅ«tras is an ancient Indian text on of philosophy composed by (also Gotama; c. ...
 name = David Hilbert  image = Hilbert1912. ...
Alaaldin abu AlHassan Ali ibn AbiHazm alQarshi alDimashqi (Arabic: Ø¹Ù„Ø§Ø¡ Ø§Ù„Ø¯ÙŠÙ† Ø£Ø¨Ùˆ Ø§Ù„ØØ³Ù† Ø¹Ù„ÙŠÙ‘ Ø¨Ù† Ø£Ø¨ÙŠ ØØ²Ù… Ø§Ù„Ù‚Ø±Ø´ÙŠ Ø§Ù„Ø¯Ù…Ø´Ù‚ÙŠ ) known as ibn AlNafis (Arabic: Ø§Ø¨Ù† Ø§Ù„Ù†ÙÙŠØ³ ), was an Arab physician who is mostly famous for being the first to describe the pulmonary circulation of the blood. ...
Abu Muhammad Ali ibn Ahmad ibn Sa`id ibn Hazm (Ø£Ø¨Ùˆ Ù…ØÙ…Ø¯ Ø¹Ù„ÙŠ Ø¨Ù† Ø§ØÙ…Ø¯ Ø¨Ù† Ø³Ø¹ÙŠØ¯ Ø¨Ù† ØØ²Ù…) (November 7, 994 â€“ August 15, 1069) was an Andalusian Muslim philosopher and theologian of Persian descent [1] born in CÃ³rdoba, present day Spain. ...
Taqi alDin Ahmad Ibn Taymiyyah (Arabic: )(January 22, 1263  1328), was a Sunni Islamic scholar born in Harran, located in what is now Turkey, close to the Syrian border. ...
Saul Aaron Kripke (born in November 13, 1940 in Bay Shore, New York) is an American philosopher and logician now emeritus from Princeton and teaches as distinguished professor of philosophy at CUNY Graduate Center. ...
Mozi (Chinese: ; pinyin: ; WadeGiles: Mo Tzu, Lat. ...
For other uses, see Nagarjuna (disambiguation). ...
Indian postage stamp depicting (2004), with the implication that he used (à¤ªà¤¾à¤£à¤¿à¤¨à¤¿; IPA ) was an ancient Indian grammarian from Gandhara (traditionally 520â€“460 BC, but estimates range from the 7th to 4th centuries BC). ...
Giuseppe Peano Giuseppe Peano (August 27, 1858 â€“ April 20, 1932) was an Italian mathematician and philosopher best known for his contributions to set theory. ...
Charles Sanders Peirce (IPA: /pÉs/), (September 10, 1839 â€“ April 19, 1914) was an American polymath, physicist, and philosopher, born in Cambridge, Massachusetts. ...
Hilary Whitehall Putnam (born July 31, 1926) is an American philosopher who has been a central figure in Western philosophy since the 1960s, especially in philosophy of mind, philosophy of language, and philosophy of science. ...
For people named Quine, see Quine (surname). ...
Bertrand Arthur William Russell, 3rd Earl Russell, OM, FRS, (18 May 1872 â€“ 2 February 1970), was a British philosopher, logician, mathematician, advocate for social reform, and pacifist. ...
Albert Thoralf Skolem (May 23, 1887  March 23, 1963) was a Norwegian mathematician. ...
Shahab alDin Yahya asSuhrawardi (from the ArabicØ´Ù‡Ø§Ø¨ Ø§Ù„Ø¯ÙŠÙ† ÙŠØÙŠÙ‰ Ø³Ù‡Ø±ÙˆØ±Ø¯Ù‰, also known as Sohrevardi) (born 1153 in NorthWestIran; died 1191 in Aleppo) was a persian philosopher and Sufi, founder of School of Illumination, one of the most important islamic doctrine in Philosophy. ...
// Alfred Tarski (January 14, 1902, Warsaw, Russianruled Poland â€“ October 26, 1983, Berkeley, California) was a logician and mathematician who spent four decades as a professor of mathematics at the University of California, Berkeley. ...
Alan Mathison Turing, OBE, FRS (pronounced ) (23 June 1912 â€“ 7 June 1954) was an English mathematician, logician and cryptographer. ...
Alfred North Whitehead, OM (February 15, 1861, Ramsgate, Kent, England â€“ December 30, 1947, Cambridge, Massachusetts, U.S.) was an Englishborn mathematician who became a philosopher. ...
Lotfali Askar Zadeh (born February 4, 1921) is a mathematician and computer scientist, and a professor of computer science at the University of California, Berkeley. ...
This is a list of topics in logic. ...
For a more comprehensive list, see the List of logic topics. ...
This is a list of mathematical logic topics, by Wikipedia page. ...
Algebra of sets George Boole Boolean algebra Boolean function Boolean logic Boolean homomorphism Boolean Implicant Boolean prime ideal theorem Booleanvalued model Boolean satisfiability problem Booles syllogistic canonical form (Boolean algebra) compactness theorem Complete Boolean algebra connective  see logical operator de Morgans laws Augustus De Morgan duality (order...
Set theory Axiomatic set theory Naive set theory Zermelo set theory ZermeloFraenkel set theory KripkePlatek set theory with urelements Simple theorems in the algebra of sets Axiom of choice Zorns lemma Empty set Cardinality Cardinal number Aleph number Aleph null Aleph one Beth number Ordinal number Well...
A logician is a person, such as a philosopher or mathematician, whose topic of scholarly study is logic. ...
This is a list of rules of inference. ...
This is a list of paradoxes, grouped thematically. ...
This is a list of fallacies. ...
In logic, a set of symbols is frequently used to express logical constructs. ...
