_Exceptive Propositions._


270. An Exceptive Proposition is so called as affirming the
predicate of the whole of the subject, with the exception of a certain
part, e.g. 'All the jury, except two, condemned the prisoner.'

271. This form of proposition again involves two distinct
statements, one negative and one affirmative, being equivalent to 'Two
of the jury did not condemn the prisoner; and all the rest did.'

272. The exceptive proposition is merely an affirmative way of
stating the exclusive--

No not-A is B = All not-A is not-B.

No one but the sage is sane = All except the sage are mad.



_Tautologous or Identical Propositions_


273. A Tautologous or Identical proposition affirms the subject of
itself, e.g. 'A man's a man,' 'What I have written, I have written,'
'Whatever is, is.' The second of these instances amounts formally to
saying 'The thing that I have written is the thing that I have
written,' though of course the implication is that the writing will
not be altered.