Talk:List of valid argument forms

Article needs rewriting from scratch
I thought at first to simply fix this article's problems but eventually realized this was going to be a bigger undertaking than I'd first thought. This article has no clear goal (is it intended as a complete list, an arbitrarily selected partial list, or an expository article?), the exposition is incompetent, and it so many problems it really needs to be rewritten completely from scratch. Here are some of the more egregious problems.


 * 1) The article is inconsistent about depth of explanation. Whereas no explanations are offered for any of the valid syllogistic forms, every valid propositional form is explained.
 * 2) The article is inconsistent about completeness. Whereas the list of 24 valid syllogistic forms is complete, the list of 5 valid propositional forms represents only about a quarter of the widely recognized such.  Perhaps completeness and explanatory depth together turned out to be too ambitious.
 * 3) The article considers no other logics besides syllogistic and propositional logic. Absent some unifying reason for this particular combination the article should be named something like "list of valid argument forms in syllogistic logic and propositional logic" or "list of valid argument forms treated by Copi" to properly reflect its scope.
 * 4) Instead of summarizing the body as required by WP:LEDE the lead gives a definition of validity and says nothing else about what to expect in the body.
 * 5) The definition of validity in the lead is both incoherent and incorrect. It states that an argument is "valid because if the premises are true, then the conclusion has to be true."  Besides being incoherent as a definition, it confuses truth with validity by making no mention of "for all interpretations."  The next sentence mentions truth tables and could be turned into a correct definition of validity for propositional logic by explaining that a truth table enumerates all 2^n interpretations of the n propositional variables.  However validity for syllogistic logic cannot be defined using truth tables.
 * 6) The article uses terms such as "unconditionally valid" and "conditionally valid" with no explanation of what they mean or links to articles that might define them.
 * 7) Variables such as "S" and "M" appear with no explanation of what they refer to.
 * 8) The definition given for Modus Ponens is that of material implication. It should say that if each of A→B and A are valid, namely always true (in all interpretations, or all worlds), then so is B.
 * 9) The article inappropriately conflates the notions of hypothetical syllogism and slippery slope.

And so on. Major rewrite needed. It's embarrassingly bad as it stands. Vaughan Pratt (talk) 21:03, 26 December 2013 (UTC)


 * Many years later... I agree the article is pretty bad. In fact, I would say this article is so bad I doubt it really needs to exist. The information on Aristotelian syllogisms is all present in the Wiki article on that subject. The information about propositional logic is of little use. It is not true at all that there are very few valid forms. There are infinitely many. Dezaxa (talk) 13:58, 8 March 2024 (UTC)