(September 20, 2012 at 8:52 pm)Rhythm Wrote: Do you often draw a positive conclusion from a negative premise that is so conveniently nestled within your premises to begin with Mystic?
I'm confused as to what you mean.
A -> B = Not B -> Not A.
They mean the same thing. If this is what you are asking about.
A->B
Not B
Therefore Not A.
Is logically valid.