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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). In Logic, an argument is a Set of one or more Declarative sentences (or "propositions") known as the Premises along Logic is the study of the principles of valid demonstration and Inference. The term validity (also called logical truth, analytic truth, or necessary truth) as it occurs in Logic refers generally to a property of

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Types of fallacies

In logical arguments, fallacies are either formal or informal. In Logic, an argument is a Set of one or more Declarative sentences (or "propositions") known as the Premises along 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 philosophy, a formal fallacy or a logical fallacy is a pattern of reasoning which is always wrong An Informal fallacy is an argument whose stated premises fail to support their proposed conclusion

Beginning with Aristotle, informal fallacies have generally been placed in one of several categories, depending on the source of the fallacy. Aristotle (Greek Aristotélēs) (384 BC – 322 BC was a Greek philosopher a student of Plato and teacher of Alexander the Great. There are fallacies of relevance, fallacies involving causal reasoning, and fallacies resulting from ambiguities (or equivocations). Equivocation is classified as both a formal and Informal fallacy. Most common forms of fallacies are evident in political speeches.

Recognizing fallacies in actual arguments may be difficult since arguments are often structured using rhetorical patterns that obscure the logical connections between assertions. Rhetoric has had many definitions no simple definition can do it justice Fallacies may also exploit the emotional or intellectual weaknesses of the interlocutor. An emotion is a mental and physiological state associated with a wide variety of feelings thoughts and behaviours Having the capability of recognizing logical fallacies in arguments reduces the likelihood of such an occurrence.

A different approach to understanding and classifying fallacies is provided by argumentation theory; see for instance the van Eemeren, Grootendorst reference below. Argumentation theory, or argumentation, embraces the arts and sciences of civil debate Dialogue, conversation and persuasion studying rules of Inference In this approach, an argument is regarded as an interactive protocol between individuals which attempts to resolve a disagreement. In International politics, protocol is the Etiquette of Diplomacy and affairs of state 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.

Fallacious arguments involve not only formal logic but also causality. Mathematical logic is a subfield of Logic and Mathematics with close connections to Computer science and Philosophical logic. Causality (but not causation) denotes a necessary relationship between one event (called cause and another event (called effect) which is the direct consequence 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. Implicature is a technical term in the linguistic branch of Pragmatics coined by Paul Grice.

Note that providing a critique of an argument has no relation to the truth of the conclusion. The meaning of the word truth extends from Honesty, Good faith, and Sincerity in general to agreement with Fact or Reality A conclusion is a Proposition, which is arrived at after the consideration of Evidence, Arguments or Premises Logic The conclusion could very well be true, while the argument as to why the conclusion is true is not valid. See argument from fallacy. The argument from fallacy, also known as argumentum ad logicam or fallacy fallacy, is a Logical fallacy which assumes that if an Argument is

Material fallacies

The classification of material fallacies widely adopted by modern logicians and based on that of Aristotle, Organon (Sophistici elenchi), is as follows:

Example

James argues:

  1. Cheese is food.
  2. Food is delicious.
  3. Therefore, cheese is delicious.

This argument claims to prove that cheese is delicious. This particular argument has the form of a categorical syllogism. A syllogism, or logical appeal, (συλλογισμός &mdash "conclusion" "inference" (usually the categorical syllogism) is a kind of 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. Cheese is a Food made from Milk, usually the milk of cows, Buffalo, Goats or sheep, by coagulation. 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:

In all but the first interpretation, the above syllogism would then fail to have validated its second premise. In Logic an interpretation gives meaning to an artificial or Formal language or to a sentence of such a language by assigning a denotation (extension 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; 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 has traditionally described a type of Logical fallacy (also called petitio principii) in which the proposition

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.

Example 1

Barbara argues:

  1. Andre is a good tennis player.
  2. 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. Ambiguity (Am-big-u-i-ty is the property of being ambiguous, where a Word, term notation sign Symbol, Phrase, sentence, or any 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. Equivocation is classified as both a formal and Informal fallacy.

Example 2

Jason argues:

  1. Nothing is better than eternal happiness.
  2. Eating a hamburger is better than nothing.
  3. Therefore, eating a hamburger is better than eternal happiness.

This argument has the appearance of an inference that applies transitivity of the two-placed relation is better than, which in this critique we grant is a valid property. In Mathematics, a Binary relation R over a set X is transitive if whenever an element a is related to an element b 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

A potato is better than eternal happiness.

In fact it is semantically equivalent to the following universal quantification:

Everything fails to be better than eternal happiness. In Predicate logic, universal quantification is an attempt to formalize the notion that something (a Logical predicate) is true for everything, or every

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

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:

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 has traditionally described a type of Logical fallacy (also called petitio principii) in which the proposition Philosophy is the study of general problems concerning matters such as existence knowledge truth beauty justice validity mind and language Deductive reasoning is Reasoning which uses deductive Arguments to move from given statements ( Premises to Conclusions which must be true if the In Logic, an argument is a Set of one or more Declarative sentences (or "propositions") known as the Premises along The term validity (also called logical truth, analytic truth, or necessary truth) as it occurs in Logic refers generally to a property of

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 – . In Mathematical logic, a Logical system has the soundness property If and only if its Inference rules prove only formulas that are

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). The argument from fallacy, also known as argumentum ad logicam or fallacy fallacy, is a Logical fallacy which assumes that if an Argument is 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. An appeal to authority or argument by authority is a type of argument in Logic called a fallacy 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. Probability is the likelihood or chance that something is the case or will happen Causality (but not causation) denotes a necessary relationship between one event (called cause and another event (called effect) which is the direct consequence

Example

An image depicting a common logical fallacy.
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:

  1. Most Rimnars are Jornars.
  2. Most Jornars are Dimnars.
  3. Therefore, most Rimnars are Dimnars.

This is fallacious. And so is this:

  1. The average family has 2. 5 children.
  2. The Smiths are a very average family.
  3. Therefore, the Smiths must have 2 or 3 children.

Indeed, there is no logical principle that states:

  1. For some x, P(x).
  2. For some x, Q(x).
  3. Therefore for some x, P(x) and Q(x).

An easy way to show the above inference is invalid is by using Venn diagrams. Venn diagrams or set diagrams are Diagrams that show all hypothetically possible Logical relations between a finite collection of sets (groups In logical parlance, the inference is invalid, since under at least one interpretation of the predicates it is not validity preserving.

Other systems of classification

Of other classifications of fallacies in general the most famous are those of Francis Bacon and J. S. Mill. Francis Bacon 1st Viscount St Alban KC QC (22 January 1561 – 9 April 1626 was an English Philosopher, Statesman, and author John Stuart Mill (20 May 1806 &ndash 8 May 1873 British Philosopher, political economist, civil servant and Member of Parliament, was an influential Bacon (Novum Organum, Aph. The Novum Organum is a philosophical work by Francis Bacon published in 1620. 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.

Fallacies in the media and politics

"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. A pundit is someone who offers to mass-media his/her opinion or commentary on a particular subject area (most typically political analysis, the Social sciences "Popular press" redirects here note that the University of Wisconsin Press publishes under the imprint "The Popular Press" Politics Politics is the process by which groups of people make decisions 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. An ad hominem argument, also known as argumentum ad hominem ( Latin: "argument to the man" "argument against the man" 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:

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. An appeal to authority or argument by authority is a type of argument in Logic called a fallacy A classic example is the ipse dixit—"He himself said it" argument—used throughout the Middle Ages in reference to Aristotle. Aristotle (Greek Aristotélēs) (384 BC – 322 BC was a Greek philosopher a student of Plato and teacher of Alexander the Great. 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 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 . Rationality as a term is related to the idea of Reason, a word which following Webster's may be derived as much from older terms referring to An expert witness is a Witness, who by virtue of Education, Training, Skill, or Experience, is believed to have Knowledge 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.

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 term validity (also called logical truth, analytic truth, or necessary truth) as it occurs in Logic refers generally to a property of 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 The challenge to the interlocutor is, of course, to discover the false premise, i. A false Premise is an incorrect Proposition that forms the basis of a logical Syllogism. e. the premise that makes the argument unsound. In Mathematical logic, a Logical system has the soundness property If and only if its Inference rules prove only formulas that are

See also

References

External links

Dictionary

fallacy

-noun

  1. Deceptive or false appearance; deceitfulness; that which misleads the eye or the mind; deception.
  2. (logic) An argument, or apparent argument, which professes to be decisive of the matter at issue, while in reality it is not.
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