This redirect does not require a rating on Wikipedia's
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|
Original Proposition |
Obversion |
Contrapositive |
Obverted Contrapositive |
(A) All S is P |
(E) No S is non-P |
(E) No non-P is S |
(A) All non-P is non-S |
(E) No S is P |
(A) All S is non-P |
(I) Some non-P is S |
(O) Some non-P is not non-S |
(I) Some S is P |
(O) Some S is not non-P |
None |
None |
(O) Some S is not P |
(I) Some S is non-P |
(I) Some non-P is S |
(O) Some non-P is not non-S |
Hoping for feedback. Amerindianarts 09:27, 7 September 2005 (UTC)
I disagree with merging the articles.
I think the reason for the recent edit "Added clarification on exactly what contraposition is" is erroneous. Irving Copi as well as other logicians drop the usage of the term "contraposition" when referring to inferences using other than categorical propositions, preferring to cite the rule of transposition for material implication and preserving "contraposition" for the process of inference in traditional logic. I Also cite the Encyclopedia of Philosophy, Susan Stebbing, and just about every other Logic book I have seen.
Read the rest of the article if you haven't already. The rule of transposition is referred to. I will wait (shortly) for a response and source before considering a revert. Amerindianarts 22:08, 31 March 2006 (UTC)
If "contraposition" is a term of mathematics, then perhaps the current article should either be renamed "contraposition (logic)" or sections on "traditional logic" and "mathematical" added, or perhaps even a new article "contraposition (mathematics)" authored. The problem is that the statement "Starting with a proposition α→β we use the classical logic proof rule contraposition to deduce the contrapositive" is not proper to the current context (philosophical logic) of the article, and in fact an error. The reasons are:
As written, this article is incredibly inaccessible. In fact, after scouring the page I found it very difficult to find contraposition as I know it: (P Q) (not-Q not-P). Everything is so buried in quantifiers and philosophical discourse that almost no college student will be able to digest it.-- Rschwieb 21:52, 17 July 2006 (UTC)
No offense meant to anyone--I'm well aware that things can very easily get carried away. This encyclopedia is NOT aimed at college students. Contrapositives are a very, very basic concept in logic and absolutely crucial to understanding logic and mathematics (how could one understand, say, an indirect geometric proof without knowing how contrapositives work?)... and it's a sad thing that Wikipedia doesn't have a decent explanation of it. This page is SO high-level as to be worthless to anyone who's not (at least) knee-deep into college-level math and logic classes.
So, I'll wait a few days, then if no one objects, I'll kill the redirect from contrapositive and write a little stub in its place. I'm no expert on logic, but I know what a contrapositive is well enough to make other people's quests for contrapositive-related knowledge a bit easier. Matt Yeager ♫ ( Talk?) 23:14, 30 November 2006 (UTC)
I'm an expert in the use of contraposition in traditional logic and it is not the same concept as used in mathematics. The term in an indirect proof in logic is the "rule of transposition". So, no you're not an expert and I'll revert any redirect. Contrapositive is already redirected here. I suggest you research the concept in mathematics and do something. In philosophical logic the term "contraposition" is rarely used in symbolism, and is commonly used as the process described in Aristotelian argumentation by means of natural language. This article is based upon a freshman level text book, so any deficiencies are on your part. Your assumption that Wiki is not directed toward towards college student is entirely off the wall and a misconception. Most of the better contributors have gone beyond that level and Wiki DOES in their guidelines try to actively recruit experts in different fields. Amerindianarts 04:39, 1 December 2006 (UTC)
Yes, you moved it to a page on contraposition in mathematics and if you view the talk page there everybody is confused by it. Amerindianarts ( talk) 09:33, 2 May 2009 (UTC)
At least the lede should be accessible to a general audience, even if the body is not. The table seems to contain irrelevant E and I statements. And the distinction between contraposition and the contrapositive in mathematics is not clearly addressed. I know a little math, very little logic, came here to clarify something, and was disappointed. Jd2718 ( talk) 20:44, 8 May 2011 (UTC)
This redirect does not require a rating on Wikipedia's
content assessment scale. It is of interest to the following WikiProjects: | |||||||||||||||||||||||
|
Original Proposition |
Obversion |
Contrapositive |
Obverted Contrapositive |
(A) All S is P |
(E) No S is non-P |
(E) No non-P is S |
(A) All non-P is non-S |
(E) No S is P |
(A) All S is non-P |
(I) Some non-P is S |
(O) Some non-P is not non-S |
(I) Some S is P |
(O) Some S is not non-P |
None |
None |
(O) Some S is not P |
(I) Some S is non-P |
(I) Some non-P is S |
(O) Some non-P is not non-S |
Hoping for feedback. Amerindianarts 09:27, 7 September 2005 (UTC)
I disagree with merging the articles.
I think the reason for the recent edit "Added clarification on exactly what contraposition is" is erroneous. Irving Copi as well as other logicians drop the usage of the term "contraposition" when referring to inferences using other than categorical propositions, preferring to cite the rule of transposition for material implication and preserving "contraposition" for the process of inference in traditional logic. I Also cite the Encyclopedia of Philosophy, Susan Stebbing, and just about every other Logic book I have seen.
Read the rest of the article if you haven't already. The rule of transposition is referred to. I will wait (shortly) for a response and source before considering a revert. Amerindianarts 22:08, 31 March 2006 (UTC)
If "contraposition" is a term of mathematics, then perhaps the current article should either be renamed "contraposition (logic)" or sections on "traditional logic" and "mathematical" added, or perhaps even a new article "contraposition (mathematics)" authored. The problem is that the statement "Starting with a proposition α→β we use the classical logic proof rule contraposition to deduce the contrapositive" is not proper to the current context (philosophical logic) of the article, and in fact an error. The reasons are:
As written, this article is incredibly inaccessible. In fact, after scouring the page I found it very difficult to find contraposition as I know it: (P Q) (not-Q not-P). Everything is so buried in quantifiers and philosophical discourse that almost no college student will be able to digest it.-- Rschwieb 21:52, 17 July 2006 (UTC)
No offense meant to anyone--I'm well aware that things can very easily get carried away. This encyclopedia is NOT aimed at college students. Contrapositives are a very, very basic concept in logic and absolutely crucial to understanding logic and mathematics (how could one understand, say, an indirect geometric proof without knowing how contrapositives work?)... and it's a sad thing that Wikipedia doesn't have a decent explanation of it. This page is SO high-level as to be worthless to anyone who's not (at least) knee-deep into college-level math and logic classes.
So, I'll wait a few days, then if no one objects, I'll kill the redirect from contrapositive and write a little stub in its place. I'm no expert on logic, but I know what a contrapositive is well enough to make other people's quests for contrapositive-related knowledge a bit easier. Matt Yeager ♫ ( Talk?) 23:14, 30 November 2006 (UTC)
I'm an expert in the use of contraposition in traditional logic and it is not the same concept as used in mathematics. The term in an indirect proof in logic is the "rule of transposition". So, no you're not an expert and I'll revert any redirect. Contrapositive is already redirected here. I suggest you research the concept in mathematics and do something. In philosophical logic the term "contraposition" is rarely used in symbolism, and is commonly used as the process described in Aristotelian argumentation by means of natural language. This article is based upon a freshman level text book, so any deficiencies are on your part. Your assumption that Wiki is not directed toward towards college student is entirely off the wall and a misconception. Most of the better contributors have gone beyond that level and Wiki DOES in their guidelines try to actively recruit experts in different fields. Amerindianarts 04:39, 1 December 2006 (UTC)
Yes, you moved it to a page on contraposition in mathematics and if you view the talk page there everybody is confused by it. Amerindianarts ( talk) 09:33, 2 May 2009 (UTC)
At least the lede should be accessible to a general audience, even if the body is not. The table seems to contain irrelevant E and I statements. And the distinction between contraposition and the contrapositive in mathematics is not clearly addressed. I know a little math, very little logic, came here to clarify something, and was disappointed. Jd2718 ( talk) 20:44, 8 May 2011 (UTC)