PHIL 120 Lecture Notes - Modus Ponens, Modus Tollens
Document Summary
*if you win, then you have a ticket. = only if you have a ticket, you win. *if you have fire, then you have oxygen. = only if you have oxygen, you have a fire. Alfred will pass only if he concentrates provided that the text is not readable [ambiguous] 2 types of interpretation (1) alfred will pass only if he concentrates, provided that the text is not readable. Not readable -> alfred will pass only if he concentrates (not readable -> (alfred passes -> alfred concentrates)) (2) alfred will pass, only if he concentrates provided that the text is not readable. Alfred will pass -> alfred concentrates provided that the text is not readable. Alfred will pass -> (text is not readable -> alfred concentrates) P -> q <= modus ponens transmits truth! *** mt (modus tollens) : p -> q. Q rules may never be applied to the internal formula.
