NAMES AND PROPOSITIONS. 



§ 3. Although Hobbes' theory of 

 Predication has not, in the terms in 

 which he stated it, met with a very 

 favourable reception from subsequent 

 thinkers, a theory virtually identical 

 with it, and not by any means so 

 perspicuously expressed, may almost 

 be said to have taken the rank of an 

 established opinion. The most gener- 

 ally received notion of Predication 

 decidedly is that it consists in refer- 

 ring something to a class, i.e., either 

 placing an individual under a class, 

 or placing one class under another 

 class. Thus, the proposition, Man is 

 mortal, asserts, according to this 

 view of it, that the class man is in- 

 cluded in the class mortal. "Plato 

 is a philosopher," asserts that the 

 individual Plato is one of those who 

 compose the class philosophers. If 

 the proposition is negative, then, 

 instead of placing something in a 

 class, it is said to exclude something 

 from a class. Thus, if the following 

 be the proposition. The elephant is 

 not carnivorous ; what is asserted 

 (according to this theory) is, that the 

 elephant is excluded from the class 

 carnivorous, or is not numbered among 

 the things comprising that class. 

 There is no real difference, except in 

 language, between this theory of Pre- 

 dication and the theory of Hobbes. 

 For a class ia absolutely nothing but 

 an indefinite number of individuals 

 denoted by a general name. The 

 name given to them in common, is 

 what makes them a class. To refer 

 anything to a class, therefore, is to 

 look upon it as one of the things 

 which are to be called by that common 

 name. To exclude it from a class, 

 is to say that the common name is 

 not applicable to it. 



How widely these views of predi- 

 cation have prevailed, is evident from 

 this, that they are the basis of the 

 celebrated dictum de omni et nvllo. 

 When the syllogism is resolved, by 

 all who treat of it, into an inference 

 that what is true of a class is true of 

 all things whatever that belong to 

 the claes ; and when this is laid down 



by almost all professed logicians as 

 the ultimate principle to which all 

 reasoning owes its validity ; it is clear 

 that in the general estimation of 

 logicians, the propositions of which 

 reasonings are composed can be the 

 expression of nothing but the process 

 of dividing things into classes, and 

 referring everything to its proper 



This theory appears to me a signal 

 example of a logical error very often 

 committed in logic, that of Harepov 

 trp&repov, or explaining a thing by 

 something which presupposes it, 

 When I say that snow is white, I 

 may and ought to be thinking of snow 

 as a class, because I am asserting a 

 proposition as true of all snow : but 

 I am certainly not thinking of white 

 objects as a class ; I am thinking of 

 no white object whatever except 

 snow, but only of that, and of the 

 sensation of white which it gives me. 

 When, indeed. I have judged, or 

 assented to the propositions, that 

 snow is white, and that several other 

 things are also white, I gradually 

 begin to think of white objects as a 

 class, including snow and those other 

 things. But this is a conception 

 which followed, not preceded, those 

 judgments, and therefore cannot be 

 given as an explanation of them 

 Instead of explaining the effect by 

 the cause, this doctrine explains the 

 cause by the effect, and is, I conceive, 

 founded on a latent misconception of 

 the nature of classification. 



There is a sort of language very 

 generally prevalent in these discus- 

 sions, which seems to suppose that 

 classification is an arrangement and 

 grouping of definite and known indi- 

 viduals : that when names were im- 

 posed, mankind took into considera- 

 tion all the individual objects in the 

 imiverse, distributed them into parcels 

 or lists, and gave to the objects of 

 each list a common name, repeating 

 this operation toties quoties until they 

 had invented all the general names 

 of which language consists ; which 

 having been once done, if a question 



