Reductio ad absurdum and proof by contradiction are logically distinct methods of argument.
the verdict
REFUTED
the evidence says no
refutedsupported
the weight of evidence
0 sources for · 5 against
Standard logical and mathematical references state that reductio ad absurdum and proof by contradiction are equivalent methods rather than logically distinct ones.
Argument is live of law, explaining the correct way of legal reasoning is of great importance in deducting legal judgment. Sometimes, it is practically useful to prove a proposition indirectly rather than directly. Ad Absurdum Argument is a special mode of indirect proof by contradiction that seeks to establish a contention by deriving an absurdity from its denial.In legal theory, the ad absurdum argumentation is normally analyzed as a kind of logical reasoning. Reductio ad Absurdum is one of the main functions of reason in deducting various legal issues. According to historians, the origin of ad absurdum argumentation and its application in scientific controversies can be traced back to antiquity, i.e., the era of the Megarians and the Elias[1]. In fact, the use of argumentation ad absurdum as a valid form of reasoning comes from the ancient Greek mathematics and the expression "hê eis to adunaton apagôgê", meaning reduction to the impossible[2] or absurdity, and can be found in Aristotle. In the new logic, this argument is considered as a special form of reduction to the impossible. This is an indirect method of proof that requires the assumption of the contradiction of what one wants to prove (self-contradiction) and then deducing logical implications from this assumption that are inconsistent with each other.In contemporary literature regarding legal reasoning, two different types of ad absurdum argument have been recognized: the strictly logical form which rise to the in
Argument is live of law, explaining the correct way of legal reasoning is of great importance in deducting legal judgment. Sometimes, it is practically useful to prove a proposition indirectly rather than directly. Ad Absurdum Argument is a special mode of indirect proof by contradiction that seeks to establish a contention by deriving an absurdity from its denial.In legal theory, the ad absurdum argumentation is normally analyzed as a kind of logical reasoning. Reductio ad Absurdum is one of the main functions of reason in deducting various legal issues. According to historians, the origin of ad absurdum argumentation and its application in scientific controversies can be traced back to antiquity, i.e., the era of the Megarians and the Elias[1]. In fact, the use of argumentation ad absurdum as a valid form of reasoning comes from the ancient Greek mathematics and the expression "hê eis to adunaton apagôgê", meaning reduction to the impossible[2] or absurdity, and can be found in Aristotle. In the new logic, this argument is considered as a special form of reduction to the impossible. This is an indirect method of proof that requires the assumption of the contradiction of what one wants to prove (self-contradiction) and then deducing logical implications from this assumption that are inconsistent with each other.In contemporary literature regarding legal reasoning, two different types of ad absurdum argument have been recognized: the strictly logical form which rise to the in
That is, 2 = n0(n0+1). Then for n=n0+1, 2 can be rewritten 2(n0+1) + 2. Since 2 = n0(n0+1), 2n0+1 + 2 = 2(n0+1) + 2n0(n0+1). So 2(n0+1) + 2n0(n0+1)= 2(n0+1)(n0 + 2), which completes the proof. Proof by contradiction
Proof by contradiction is a way of proving a mathematical theorem by showing that if the statement were false, then there would be a logical contradiction involved. That is, if one of the results of the theorem is assumed to be false, then there would be some inconsistency with the logic. When proving a theorem by way of contradiction, it is important to note that in the beginning of the proof. This is usually abbreviated BWOC. When the contradiction appears in the proof, there is usually a ⨳ symbol involved.[2]
Related pages
- Constructive proof
- Direct proof
- Mathematical logic
- Q.E.D. - Quadratic equation, which can be solved using a kind of proof called "completing the square"
- Reductio ad absurdum
References
- ↑ Bill Casselman. "One of the Oldest Extant Diagrams from Euclid". University of British Columbia. Retrieved September 26, 2008. - 1 2 "The Definitive Glossary of Higher Mathematical Jargon". Math Vault. 2019-08-01. Retrieved 2020-09-23.
A mathematical proof is a deductive argument for a mathematical statement, showing that the stated assumptions logically guarantee the conclusion. The argument may use other previously established statements, such as theorems; but every proof can, in principle, be constructed using only certain basic or original assumptions known as axioms, along with the accepted rules of inference. Proofs are examples of exhaustive deductive reasoning that establish logical certainty, to be distinguished from empirical arguments or non-exhaustive inductive reasoning that establish "reasonable expectation". Presenting many cases in which the statement holds is not enough for a proof, which must demonstrate that the statement is true in all possible cases. A proposition that has not been proved but is believed to be true is known as a conjecture, or a hypothesis if frequently used as an assumption for further mathematical work.
Proofs employ logic expressed in mathematical symbols, along with natural language that usually admits some ambiguity. In most mathematical literature, proofs are written in terms of rigorous informal logic. Purely formal proofs, written fully in symbolic language without the involvement of natural language, are considered in proof theory. The distinction between formal and informal proofs has led to much examination of current and historical mathematical practice, quasi-empiricism in mathematics, and so-called folk mathematics, oral traditions in the mainstream mathematical community or in other cultures. The philosophy of mathematics is concerned with the role of language and logic in proofs, and mathematics as a language.
The word proof derives from the Latin probare 'to test'; related words include English probe, probation, and probability, as well as Spanish probar 'to taste' (sometimes 'to touch' or 'to test'), Italian provare 'to try', and German probieren 'to try'. The legal term probity means authority or credibility, the power of testimony to prove facts when given by persons of reputation or status.
Plausibility arguments using heuristic devices such as pictures and analogies preceded strict mathematical proof. It is likely that the idea of demonstrating a conclusion first arose in connection with geometry, which originated in practical problems of land measurement. The development of
In proof by contradiction, also known by the Latin phrase reductio ad absurdum (by reduction to the absurd), it is shown that if some statement is assumed true, a logical contradiction occurs, hence the statement must be false. A famous example involves the proof that
2
{\displaystyle {\sqrt {2}}}
is an irrational number:
A probabilistic proof is one in which an example is shown to exist, with certainty, by using methods of probability theory. Probabilistic proof, like proof by construction, is one of many ways to prove existence theorems.
In the probabilistic method, one seeks an object having a given property, starting with a large set of candidates. One assigns a certain probability for each candidate to be chosen, and then proves that there is a non-zero probability that a chosen candidate will have the desired property. This does not specify which candidates have the property, but the probability could not be positive without at least one.
A probabilistic proof is not to be confused with an argument that a theorem is 'probably' true, a 'plausibility argument'. The work toward the Collatz conjecture shows how far plausibility is from genuine proof, as does the disproof of the Mertens conjecture. While most mathematicians do not think that probabilistic evidence for the properties of a given object counts as a genuine mathematical proof, a few mathematicians and philosophers have argued that at least some types of probabilistic evidence (such as Rabin's probabilistic algorithm for testing primality) are as good as genuine mathematical proofs.
A nonconstructive proof establishes that a mathematical object with a certain property exists—without explaining how such an object can be found. Often, this takes the form of a proof by contradiction in which the nonexistence of the object is proved to be impossible. In contrast, a constructive proof establishes that a particular object exists by providing a method of finding it. The following famous example of a nonconstructive proof shows that there exist two irrational numbers a and b such that
a
b
{\displaystyle a^{b}}
is a rational number. This proof uses that
2
{\displaystyle {\sqrt {2}}}
is irrational (an easy proof is known since Euclid), but not that
2
2
{\displaystyle {\sqrt {2}}^{\sqrt {2}}}
is irrational (this is true, but the proof is not elementary).
simpler proof We nearly have a very useful and important method of proof know as proof by contradiction , or for those who like Latin, Reductio ad absurdum which
Absurd
The Simple English Wiktionary has a definition for:
absurd.
Absurd can refer to several different things:
- Absurdity, very poor reasoning; ridiculous, or nonsense
- Absurdism, a philosophy about how the human search some meaning in the universe and the impossibility of finding that meaning
- Absurd or surreal humour
- Absurd (band), a German heavy-metal band
- Absurd, a term used in logic to describe a contradiction
- Reductio ad absurdum, a type of logical argument
Absurd or The Absurd may refer to: == Entertainment == Absurd (band), German metal band from the 1990s "Absurd", a 1997 song by Fluke, from the album Risotto "Absurd" (song), a 2021 song by Guns N' Roses Theatre of the Absurd, art form utilizing the philosophy of Absurdism Absurd (film), 1981 Italian film Absurd or surreal humour Absurdist fiction == Philosophy and logic == Absurdity, general and technical usage—associated with extremely poor reasoning, the ridiculous, or nonsense The Absurd, the conflict between the human tendency to seek a certain meaning of life and the failure to find any Absurdism, a philosophy based on the belief that the universe is irrational and meaningless Reductio ad absurdum, a type of logical argument
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