Ed Barkmeyer wrote:
> First rule: when discoursing with logicians remember that "all"
> and "always" are reserved words. ;-) In logic, "not 100%" is
> the *opposite* of "all". A single counterexample is a disproof.
Second rule: 'opposite' is a bit vague, avoid using it unless you're its
meaning is clear.
'opposite to all' might mean:
- not all (a contradiction)
- none (a contrary) (01)
All X are Y is contradiction to Some X are not Y
All X are Y is contrary to No X are Y (02)
see 'square of opposition' in a dictionary of philosophy, or the like. (03)
(interestingly, contraries can both be false, but of two contradicting
statements, one must be false and the other true.) (04)
Message Archives: http://ontolog.cim3.net/forum/ontolog-forum/
Shared Files: http://ontolog.cim3.net/file/
Community Wiki: http://ontolog.cim3.net/wiki/
To Post: mailto:ontolog-forum@xxxxxxxxxxxxxxxx (06)