Though the definitions I have given of this pair of fallacies are conformable to the usage of most modern logicians, and are stated in a form which is most likely to be of practical service to the student, they do not exactly correspond with the original meaning of the expressions. The 'Fallacia Accidentis ' and the 'Fallacia a dicto secundum quid ad dictum simpliciter,' according to their original usage, applied to those cases in which a term, when not implying accidents, was confounded with the same term, when implying accidents. Thus, to take the common instance (which is sufficiently absurd): 'What you buy in the market you eat; raw meat is what you buy in the market; ... raw meat is what you eat.' Here it may be replied that what we buy in the market we do indeed eat, but not necessarily in the same state in which we buy it at market. This particular instance is an • As, for instance, Mill (Logic, Bk. V. ch. vi. § 4), Port Royal Logic (Part III. ch. xix. § 5, 7). The latter virtually treats both fallacies as if they were a dicto secundum quid ad dictum simpliciter. Mr. de Morgan adduces one of Boccaccio's stories as affording an amusing instance of the fallacia accidentis. It is the old example of the 'raw meat' in another form: 'A servant who was roasting a stork for his master was prevailed upon by his sweetheart to cut off a leg for her to eat. When the bird came upon table, the master desired to know what was become of the other leg. The man answered that storks had never more than one leg. The master, very angry, but determined to strike his servant dumb before he punished him, took him next day into the fields where they saw storks, standing each on one leg, as storks do. The servant turned triumphantly to his master, on which the latter shouted, and the birds put down their other legs and flew away. “Ah, sir," said the servant, "you did not shout to the stork at dinner example of the Fallacia Accidentis. From their technical meaning, these fallacies would easily pass into their present signification, which is both more intelligible and of greater practical service. I may notice one more example of the errors due to ambiguous language, viz. the fallacy of what may be called Paronymous Terms. The same word may often assume different forms, as substantive, adjective, adverb, or verb, but it does not follow, when it has assumed these different forms, that they all retain corresponding meanings. It has been already noticed that the words probably, probable, probability, though the two last are themselves ambiguous, vary in meaning according as we use the adverb, the adjective, or the substantive. Thus, if I hear some one ask the question 'What is the probability of my throwing an ace with a die at a single throw?' I cannot infer that in any single throw I shall probably throw an ace. Again, because a man has done something unjust (i. e. has committed an act which in its results is unjust), I cannot infer that he has acted unjustly (i. e. with intentional injustice), nor, even if he has acted unjustly (i. e. in one or more instances), can I infer that he is an unjust man (i. e. a man of unjust habits or character). To take an old instance, because projectors are unfit to be trusted, and this man has formed a project, it does not follow that he is unfit to be trusted. Nor from the meaning attached to the expressions, kingly, yesterday: if you had done so, he would have shewn his other leg too." nobly, gentlemanly, can we argue to the usual qualities of a king, a nobleman, or a gentleman; nor, on the meanings of the words 'to trow,' 'to represent,' can we base any sound argument as to the nature of truth, or the duties of a representative. All instances of this fallacy, when stated syllogistically, involve four terms, and so offend against the rules for the construction of a syllogism, but, as we do not ordinarily state our arguments in a syllogistic shape, and these fallacies undoubtedly impose on us through the ambiguity of language, it is better to consider them here rather than under the second head. Many other forms of fallacy may be regarded as due to ambiguities of language, but it has perhaps been the tendency of modern logicians, and especially of Whately, to overload this division of fallacies, and to treat as merely differences of language what are in reality radical differences of opinion. At the same time it cannot be denied that terms expressive of fundamental conceptions in their several sciences, such as faith, church, election, law, loyalty, federation, justice, value, capital, force, nature, natural, &c., are frequently used, in the same discussion, in the most widely divergent senses, and are consequently the source of endless confusion in our reasonings. Thus the term 'faith' may mean either a belief in certain propositions, or confidence, trust, and repose in a certain person; the word 'church' may mean the whole body of Christians (and, of course, in this sense its signification will vary according to the meaning attached to the term Christian), a particular section of Christians, a congregation meeting in a certain place, the place of meeting, and, lastly, by a strange perversion of the term, the clergy as distinguished from the laity; the term 'loyalty' may mean either attachment to the laws of a country in general, special attachment to some particular portion of the laws, or, in its most restricted sense, personal attachment to the supreme ruler; 'capital' may mean either the amount of money possessed by a trader, or his whole stock of commodities available for future production; 'natural' may express either the original condition of a thing, or the state into which it is ultimately developed, besides having countless other meanings. On account of the various significations which may be attached to the same term, it is necessary, in entering on any investigation, carefully to define the terms to be employed, and never, without express notice, to deviate from the sense thus imposed upon them. 8 The so-called 'Fallacia plurium interrogationum ' has not been noticed in the text, because it is a rhetorical artifice, rather than a logical fallacy. It consists in covertly putting as a single question what is in reality two, as, for instance, 'Are gall and honey sweet?? 'Have you cast your horns?' (known as 'cornutus'). 'What did you take, when you broke into my house last night?' given up beating your father?' The object is to entrap the respondent into an admission which he would otherwise not be likely to make. 'Have you CHAPTER IX. On Method as applied to the arrangement of Syllogisms in a Train of Reasoning. I DO not propose to treat of Method in general (for this would involve a discussion of induction and the various relations in which it stands to deductive inference), but it may be useful to the student if I offer a few remarks on Method under the limitation stated in the heading of this chapter. When syllogisms are combined in a train of reasoning, we may either commence with the conclusion, and ask what reasons we have for believing it, and then go on to ask the reason for believing the premisses, and so on, till at last we arrive at some propositions of which there is no doubt, or in which we at least can acquiesce; or else we may follow the reverse process, and commencing with propositions which are the result of some previous investigation, or which we at all events accept as true, may go on combining them with each other, till at last we arrive at some conclusion which we regard as sufficiently important to terminate our enquiries. The former method will be familiar to my readers as that by which we solve what are called 'geometrical deductions,' and in fact as the method which we generally though not |