83r17h
Puritan Board Freshman
"Not A is false" is the same thing as saying "A is true"
This is a potentially equivocal statement. The better phrasing would be "A is not false." That reduces the possibility of assuming a fallacious identity.
Meaning 1 (this is a fallacy):
B (is not) A. B is (not A). B is false. Therefore, (Not A) is false. Therefore A is true.
Meaning 2 (this is correct):
Not (A is false). Therefore A is true.
In other words: a negative argument (e.g. "Islam is false") does not imply a positive conclusion (e.g. "Christianity is true").