Talk:Contraposition (traditional logic)

message: *I would like to open a discussion about this page and the page on Contrapositive. My training is in philosophical logic and I am not a mathematician, so... The page on "contraposition" states what I know as an "obvert contrapositive", and not a contrapositive at all, in the strict sense.  The tautology it states, when considering it as an obvert contrapostive, is missing two steps.  Contraposition as an immediate inference is actually only one step in the method of deriving the tautology stated. The obvert contrapositive is immediated inferred from the contrapositive.  So, the contrapositive as stated is wrong in name, and the proof is lacking in steps. This page on "contraposition" seems to follow the example of the page on contrapositive. My example is in Aristotelian Logic.
      
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)

message: I disagree with merging the articles.
:In terms of philosophic logic the current article on the contrapositive is confused.  The contrapositive is the product of a method of inference termed "contraposition" and is limited to traditional logic, or categorical propositions.  In symbolic logic the contrapositive is eliminated in the process of transposition.  The current article on the contrapositive confuses these two types of inference and their respective applications within traditional logic and symbolic logic.  Meaning, the first part of the article on the contrapositive can be eliminated.  It is handled by the article on Transposition.  The second part of the article on the contrapositive can be merged with the article on contraposition.  I might add that this applies to logic in philosophy.  If the mathematicians have some notion of the contrapositive in symbolism other than transposition, I am not aware of it.Amerindianarts 18:09, 24 November 2005 (UTC)
replies: text: Many standard introductions to logic call transposition "contraposition".  To leave it entirely out here would be a mistake. KSchutte 22:04, 7 December 2005 (UTC)
replies: text:  The article on transposition covers its relation to contraposition.  Texts covering the rule of transposition usually don't refer to contraposition, which is a method for categorical propositions, and not material implication. The articles on contrapositive and contraposition have already been merged. Amerindianarts 22:56, 7 December 2005 (UTC)

text: Also, contraposition is a type of inference, and transposition is a rule of inference. Their respective articles imply this.  A categorical proposition can have more than one contrapositive with differences in the distribution of its terms.  For this reason Venn diagrams are useful for measuring their validity, and not truth tables, which are more appropriate for the rules, e.g. transposition. Amerindianarts 23:21, 7 December 2005 (UTC)
thread_title: Discussion on merging contrapositive and contraposition

message: 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)
thread_title: Contraposition vs transposition

message: 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)
replies: text: Obviously you intend for this article to be on traditional logic. (Which somewhat violates, say, WP:OWN, but we shall let that slide.) This has little or nothing to do with the contrapositive in mathematics, so I have moved this article to a space where it will not be confusing to anyone. Good day. Matt Yeager ♫ (Talk?) 02:15, 22 December 2006 (UTC)
thread_title: This page is awful

message: 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)
thread_title:  This page is almost completely inaccessible