Here is Hamilton's example of a disjunctive syllogism, which he considered a valid argument--'The hope of immortality is either a rational expectation or an illusion; but the hope of immortality is a rational expectation; therefore the hope of immortality is not an illusion.' It is a flagrant tautologism. *** 'If man be not a morally responsible being, he must want either the power of recognising moral good (as an intelligent agent), or the power of willing it (as a free agent); but man wants neither of these powers; therefore man is a morally responsible being.' Adopted by Hamilton from Krug and given as valid. It is first a fallacy of contrast, and if amended in this respect it would still be a fallacy of tautology. I. If m. lacked certain pp. | he would be irresp. -----------------------------+-------------------- He does _not_ lack these pp. | _N. C._ *** 'If Aeschines joined in the public rejoicings, he is inconsistent; if he did not, he is unpatriotic; but he either joined, or not, therefore he is either inconsistent or unpatriotic.'--An excellent specimen of logicians' logic: on a par with this--If it is fine weather, I go; if it rains, I stay; it must either rain or be fine, therefore I must either go or stay. *** 'If the world were eternal, the most useful arts, such as painting, &c. would be of unknown antiquity: and on the same supposition there would be records long prior to the Mosaic; and likewise the sea and land in all parts of the globe might be expected to maintain the same relative situations now as formerly: but none of these is the fact: therefore the world is not eternal.' If some things were different | the w. would be eternal from what they are | ------------------------------+------------------------ They are _not_ different | _N. C._ *** 'If the world existed from eternity, there would be records prior to the Mosaic; and if it were produced by chance, it would not bear marks of design: there are no records prior to the Mosaic, and the world does bear marks of design: therefore it neither existed from eternity, nor is it the work of chance.' Two theorems are here mixed together, both fallacies of contrast-- Existence of records | would prove the w. etern. ---------------------+-------------------------- Records do not exist | the w. is non-eternal Non-existence of marks | wd. pr. w. made by chance ---------------------+---------------------------- The marks exist | w. was not made by chance *** 'If this man were wise, he would not speak irreverently of Scripture in jest; and if he were good he would not do so in earnest; but he does it, either in jest or earnest; therefore he is either not wise or not good.' As it stands this is quite circular, but it might be rendered valid by generalisation:--