(December 3, 2009 at 7:11 am)Tiberius Wrote: I agree with that. My only problem with your argument was your assertion that because P => Q, Q => P, which is a logically invalid statement (as per my proof).
But I never said that. What I meant by Q is necessary for P was P => Q.
Ok, let's wrap it up:
By my knowledge:
- Q is necessary for P means P => Q
- Q is sufficient for P means Q => P
I always saw it being read/translated that way, but I know that definitely my knowledge is not TEH definite right way of expressing it. I mean, there is plenty of controversy about how these things should be phrased in english (even on text books).
So, can we call it a misunderstanding/diversion about the translation from english to logic (and vice-versa) of the expression "P => Q"?
That said, since we even agreed on the point that really matters to begin with, I reckon there is no more need for discussion, right? (which is a shame, it was fun)
I will keep in mind that logic + english = confusion.
"A fool says in his heart, 'There is no god.'
A wise man shouts it from the rooftops."
Mark Palmer (@ The Center for Inquiry Blasphemy Contest)
A wise man shouts it from the rooftops."
Mark Palmer (@ The Center for Inquiry Blasphemy Contest)
