THE THEORY OF SYLLOGISM, ETC. 



105 



enough if within the universe of the syllogism, either X — Y or X Y must be true. Thus 



' agrees in colour,' ' agrees in size, 1 may be alternative copula? in a universe the alternative of 

 which is that any X is either of the colour or of the size of some Y. 



When contraries are introduced, the copular condition further required is that either X — Y 

 or X y should hold for any X. 



The least abstract of all copula; is the is and is not of the logicians, when employed, 

 whether subjectively or objectively, in the sense of identity. But logicians rarely confine it to 

 that sense. It takes many meanings in their modes* of speaking and in their examples: and 

 perhaps may be stated as generally signifying agreement in some understood and, pro vice, 

 unvarying particular. I have never seen it carried further, formally at least : and I feel safe 

 in affirming that is, — used as merely satisfying the transitive and convertible conditions, with a 

 consequent right, for example, to treat it as standing for ' is brother to,' — is a more abstract 

 copula than the is of the logicians. 



I should almost presume this from the silence of the writers who distinguish between reading 

 the extension and reading the intension of a proposition, as to any other change of the copula 

 being possible. ' Every man is an animal' is read either in extension, ' All man is animal,' 

 or in intension, as by saying that the notion of animal forms part of the notion of man ; every 

 attribute of an animal is an attribute of man. Without at all denying the existence of the 

 distinction, or its metaphysical value, I feel convinced that it is not another reading of the 

 proposition, but another proposition, derived infer entially, though not syllogistically, by aid of 

 the dictum de majore et minore. For a term used universally we may substitute a lesser term ; 

 and the attribute of all animals is the attribute of all men. The proposition only says that 

 man is the lesser term ; and intensive reading is thus derived from the dictum. Invent a sub- 

 stantive, A, such that eco vi termini, the 'i of an animal,' is one in which the word animal 

 must be construed universally ; and then we may affirm that 'A of an animal' is 'A of a man.' 

 And though, undoubtedly, the word attribute, used metaphysically, will be the one most often 

 employed in place of A, yet the formal process of reading by intension will be only a case of 

 that principle on which we say that ' Englishman who does not use tobacco' is included in ' Euro- 

 pean who does not take snuff,' obtained by enlargement of the particular and diminution of the 

 universal. 



Formally speaking, the change from extension to intension is as follows ; and it will be seen 

 that a new distinction is introduced, and further, that the two modes of reading are not con- 

 vertible ; the extensive mode gives the intensive, but not vice versa in all cases. 



* But not in their formal definitions and enunciations. The 

 substantive verb is the most common definition. The Port 

 Royal Logic, which I choose from those lying before me, as 

 a work which dares to differ, or to revive, at pleasure, makes 

 its definition very distinct. " Non sufBcit hos duos terminos 

 percepisse; sed debent mente vel conjungi vel separari. Et 

 hsec mentis Operatio in Propositione notatur verbo, Est..." 



To take two extremes of the part of time in which scholastic 

 logic and printing flourished together, we have Paulus Venelus 

 (1474), "Copula semper est verbum substantivum scilicet 

 sum, es, est," — and Crackanthorp (4th ed. 1677), "Et haec 

 [sc. copula] est in omni Propositione Verbum hoc Substanti- 

 vum, Sum, es, fui, aut aliqua persona illius." 



Vol. IX. Part I. 



14 



