good; for this is false. In the same way, moreover, the judgement
concerning that which is good, that it is not good, is the contrary of
the judgement that it is good.
It is evident that it will make no difference if we universalize the
positive judgement, for the universal negative judgement will form the
contrary. For instance, the contrary of the judgement that
everything that is good is good is that nothing that is good is
good. For the judgement that that which is good is good, if the
subject be understood in a universal sense, is equivalent to the
judgement that whatever is good is good, and this is identical with
the judgement that everything that is good is good. We may deal
similarly with judgements concerning that which is not good.
If therefore this is the rule with judgements, and if spoken
affirmations and denials are judgements expressed in words, it is
plain that the universal denial is the contrary of the affirmation
about the same subject. Thus the propositions 'everything good is
good', 'every man is good', have for their contraries the propositions
'nothing good is good', 'no man is good'. The contradictory
propositions, on the other hand, are 'not everything good is good',
'not every man is good'.
It is evident, also, that neither true judgements nor true
propositions can be contrary the one to the other. For whereas, when
two propositions are true, a man may state both at the same time
without inconsistency, contrary propositions are those which state
contrary conditions, and contrary conditions cannot subsist at one and
the same time in the same subject.