modus ponens & modus tollens?

[Tim Gaines]

I'm putting TIPS to the test this morning.  In 30 minutes I'll
be talking to my Research Methods class about the logic of
testing theories, and one point I want to make is that neither
of the two logically valid modes of syllogistic reasoning
(modus ponens and modus tollens) permits confirmation of the
antecedent (the theory).  It would be nice to be able to
provide the etiology of the terms, but I have loaned my copy
of Wason and Johnson-Laird to a student, and I can't seem to
find the terms in other references I have.  Anyone know these
terms?

Thanks,

Tim
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  Tim Gaines                            [EMAIL PROTECTED]
  Professor of Psychology               phone:  864-833-8349
  Presbyterian College                  fax:  864-833-8481
  Clinton, SC  29325
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