PLYMOUTH INSTITUTION. 131 



GISM, and explained the parts of which it should properly consist, 

 he proceeded to develope the system of mode and figure, of which 

 there are said to be no less than 64 varieties ; though happily for 

 Tyros in this delectable art, only 19 are preserved, in the present 

 day, to exercise their patience and skill : and the lecturer drew 

 the attention of the society to certain mnemonic lines, composed of 

 words embodying the essential distinctions between each mode, by 

 means of which, it is asserted, all arguments may be reduced to the 

 simplest possible form required by Aristotle's fundamental axiom, 

 "Dictum de omni et nullo/' Many an amusing " exempli gratia" 

 was brought forward to elucidate this interesting process; and the 

 lecturer then advanced another stage in this critical survey of the 

 subject, to consider the treatment of that important branch of logic 

 entitled the doctrine of fallacies. Notice was taken of the sophism 

 homonymia or quibble, in which a term is used equivocally ; the 

 sophism of amphibolia or ambiguity; the fallacia accidentis; the 

 ignoratio elenchi ; the petitio principii; the fallacia consequentis ; 

 the non causa, pro causa ; and especial allusion was made to the 

 argumentum ad hominem, very frequently had recourse to by so- 

 phists when foiled in their attack on the argumentum ad rem. 



Having drawn this brief summary of the logical art, the lecturer 

 contended that the whole fabric was cumbrous, and utterly unsuited 

 to practical purposes; while its use affords equal advantages to 

 truth and error, since falsehood may lie, and often is, couched under 

 the syllogistic form ; and unless every one is supposed to be able to 

 discriminate the true syllogism from the counterfeit, what, he would 

 ask, is gained by investing argument in such meretricious trappings ? 

 He complained moreover that past experience had demonstrated the 

 injurious tendency of this study, by producing a series of sceptics, 

 dogmatics, and cavillers, whose powers were devoted to the propa- 

 gation of sentiments extremely mischievous in a moral point of 

 view; and as he believed its influence was calculated to vitiate a 

 candid disposition, to imbue the character with a carping and unsa- 

 tisfied temper, and to excite a love of victory more powerful than 

 that of truth, he should be glad to see its expulsion from every seat 

 of learning, and to know it was consigned to the guardianship of 

 those diplomatic aspirants whose spirit needed to be set on edge 

 for designing subtile purposes. If a substitute were demanded that 

 should yield all that the art of logic could really boast of utility, 

 unalloyed with the evils in question, and at the same time furnish 

 the most perfect praxis of logic as a science, he was at no loss to 

 produce one, and the regulations of some of our most erudite colle- 



