(July 20, 2015 at 9:08 am)Rhythm Wrote:(July 20, 2015 at 4:06 am)Pizza Wrote: It should be noted that arguments can be valid, but premises are false. Validity comes cheap. For example:
If apes exist, cats speak English. If P, Q.
Apes exist. P
Therefore, cats speak English. Q
(July 20, 2015 at 4:08 am)robvalue Wrote: Oh yes, for sure. Good point. Unsupported assertions will be pointed out, they are on my listBut it's very true, the argument can still be valid. The result is then only as true as its premises.
WLC likes that a lot. He talks for so long that you've lost track of the subject, then just assumes his conclusion and hopes you didn't notice.
-That- one's not actually an issue of an -unsupported assertion-. It's a mechanical issue of -material implication- whereby the "if" modifier is being leveraged improperly. Because an argument (of the type invoked) is only said to be valid when it takes a form wherein it is impossible for the assertions to be true while the conclusion is simultaneously false, and because an argument (of the type invoked) requires a specific condition which is not present...........that argument is actually -invalid-.
Validity doesn't come cheap, people have simplistic and incomplete concepts of validity, is all. "If p, then q" works as a simple description of a logical operation divorced from conditionals in natural language.......but that's the end of it's utility. The trouble is the inference of conditionals in natural language, and their translation to a logical form. If this doesn't -already- make it sound hopeless...I have some bad news......english might be one of the worst languages in the world on that count. There is no such trouble with the "if" modifier in other languages. That means that some of us are suffering from a handicap not uniform to all of us, and ironically that;s the problem with the word "if" in english. It does not describe a uniform condition, and theres no way of ensuring that the condition it descibes is the appropriate condition for the operation used, as in the statement regarding apes, cats.....and whether or not they speak english....
(for more, google downing, wilson, or goldstein et al - or, for some heavier reading not limited to this subject but containing one of the best explanations -of it- try "Causality and Determinism" by Von Wright)

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We are the United States of Amnesia, we learn nothing because we remember nothing. - Gore Vidal