critch
11-24-2007, 12:21 PM
In Chapter 9 of Traditional Logic, the conversion of an O statement does not include the quantifier of the predicate. Later, in the discussion of contraposition, the quantifier is included.
Discussion of Conversion (p. 84):
Some accountants are not men.
Converse: Some men are not accountants.
Discussion of Contraposition (p. 85):
All men are mortal.
Obvert: No men are non-mortal.
Convert: Some non-mortals are men.
Obvert: Some non-mortals are non-men.
Since the method of contraposition described would not work without including the quantifier in the conversion, is the second way correct?
Discussion of Conversion (p. 84):
Some accountants are not men.
Converse: Some men are not accountants.
Discussion of Contraposition (p. 85):
All men are mortal.
Obvert: No men are non-mortal.
Convert: Some non-mortals are men.
Obvert: Some non-mortals are non-men.
Since the method of contraposition described would not work without including the quantifier in the conversion, is the second way correct?