yes, if it becomes false, you don't apply it. Thus, there is no case where modus ponens can ever be misapplied, and your original challenge one which cannot be met. If A, then B ... I'm going to stick to talking about Wolfe.
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<div class="gmail_quote">On Fri, Oct 17, 2014 at 7:03 AM, Norwood, Frederick Hudson <span dir="ltr"><<a href="mailto:NORWOODR@mail.etsu.edu" target="_blank">NORWOODR@mail.etsu.edu</a>></span> wrote:<br>
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<p class="MsoNormal"><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:#1f497d;FONT-SIZE:11pt">António Pedro Marques is at least unabashedly post-modern, refusing to be chained by logic.<u></u><u></u></span></p>
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<p class="MsoNormal"><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:#1f497d;FONT-SIZE:11pt">You, Marc Aramini, keep confusing logic with science. Mathematics is built on logic. If the premise becomes false, then you no longer apply modus ponens. You don’t need to lose your head. Every even number is divisible by two. What if the original premise is “This number is odd.” Then the theorem doesn’t apply. It doesn’t disprove modus ponens.<u></u><u></u></span></p>
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<p class="MsoNormal"><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:#1f497d;FONT-SIZE:11pt">Rick Norwood<u></u><u></u></span></p>
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<p class="MsoNormal"><b><span style="FONT-FAMILY:'Tahoma','sans-serif';FONT-SIZE:10pt">From:</span></b><span style="FONT-FAMILY:'Tahoma','sans-serif';FONT-SIZE:10pt"> Urth [mailto:<a href="mailto:urth-bounces@lists.urth.net" target="_blank">urth-bounces@lists.urth.net</a>] <b>On Behalf Of </b>Marc Aramini<br><b>Sent:</b> Friday, October 17, 2014 9:40 AM
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<div class="h5"><br><b>To:</b> The Urth Mailing List<br><b>Subject:</b> Re: (urth) I, even I, would celebrate, in rhymes inept the great...<u></u><u></u></div></div></span>
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<p class="MsoNormal">These are linguistic truths built into the definitions themselves ... <u></u><u></u></p>
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<p class="MsoNormal">the statement if A then B is either true linguistically <u></u><u></u></p></div>
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<p class="MsoNormal">or it isn't, in which case the premise was wrong. It doesn't mean much else.<u></u><u></u></p></div>
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<p class="MsoNormal">ie "If I have no head I will die." technology advances, and now I can live without a head - the original premise then becomes false. Doesn't mean anything.<u></u><u></u></p></div>
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<p class="MsoNormal">On Fri, Oct 17, 2014 at 6:23 AM, Norwood, Frederick Hudson <<a href="mailto:NORWOODR@mail.etsu.edu" target="_blank">NORWOODR@mail.etsu.edu</a>> wrote:<u></u><u></u></p></div>
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<p style="MARGIN-BOTTOM:12pt" class="MsoNormal">Modus ponens is unprovable. You have to start somewhere. Is it possible that modus ponens is false? Of course it is possible. I may be a madman, and modus ponens may not say what I think it says. I may be the only creature in the universe, and modus ponens may really mean, "Thou art God." But these objections can be raised in any discussion whatsoever, and after a while most people stop raising them. If I am sane, and if modus ponens says what I think it says, then it seems to me bedrock on which to build. Further, if there are cases where A implies B, A is true, and B is false, then that ends the discussion, because every statement is both true and false, and in that case there is no point in saying anything at all.<br><br>Rick Norwood<br><br>-----Original Message-----<br>From: Urth [mailto:<a href="mailto:urth-bounces@lists.urth.net" target="_blank">urth-bounces@lists.urth.net</a>] On Behalf Of Jeffery Wilson <a href="http://clueland.com/" target="_blank">clueland.com</a><br>Sent: Friday, October 17, 2014 1:56 AM<br>To: The Urth Mailing List<br>Subject: Re: (urth) I, even I, would celebrate, in rhymes inept the great...<u></u><u></u></p>
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<p class="MsoNormal">On 10/16/2014 7:07 AM, Norwood, Frederick Hudson wrote:<br>> Jeffery Wilson: I do say A is A. That's called the reflexive property of equality. And, yes, I've read the Lewis Carroll bit. Even wrote a poem about it.<br><br>If you already know that the modus ponens is unprovable, and are familiar with reflexive equality which is axiomatic, why are you bothering to hold up modus ponens as an example of an absolute truth?<br><br>--<br>Jeff Wilson - < <a href="mailto:jwilson@clueland.com" target="_blank">jwilson@clueland.com</a> ><br>A&M Texarkana Computational Intelligence Lab < <a href="http://www.tamut.edu/cil" target="_blank">http://www.tamut.edu/cil</a> > _______________________________________________<br>Urth Mailing List<br>To post, write <a href="mailto:urth@urth.net" target="_blank">urth@urth.net</a><br>Subscription/information: <a href="http://www.urth.net/" target="_blank">http://www.urth.net</a><br>_______________________________________________<br>Urth Mailing List<br>To post, write <a href="mailto:urth@urth.net" target="_blank">urth@urth.net</a><br>Subscription/information: <a href="http://www.urth.net/" target="_blank">http://www.urth.net</a><u></u><u></u></p></div></div></blockquote>
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