THE PREDICABLES. 83 



function of a nervous system. The &quot; time and place of his birth &quot; 

 might be regarded as individual properties of any particular per 

 son. But the most important are the specif c properties, which are 

 necessarily connected with the specific nature of the class and 

 with the connotation of the class name. Thus &quot; capable of using 

 language/ &quot; tool-using,&quot; &quot; food-cooking,&quot; &quot; capable of learning,&quot; 

 and other such attributes, necessarily following from the posses 

 sion of reason, are all specific propria of man. 1 They are found 

 always in all men, and in men alone. &quot; Proprium dicitur quod 

 convenit omm, solo et semper&quot; i.e. that which is found always in 

 every member of the species, and in them alone. Since, as we have 

 already seen (32), there is a certain conventional element in fixing 

 the connotation of the name of any species in drawing the line 

 between what is &quot; directly implied &quot; or &quot; meant &quot; by a name, and 

 what is only &quot; indirectly &quot; if necessarily involved therein so, also, 

 it may be sometimes a matter of little moment which of two or 

 more attributes we regard as the differentia, and which as pro 

 pria^ of a given class : whether, for instance, we regard &quot;equality 

 of sides&quot; or &quot; equality of angles&quot; as the differentia of an equi 

 lateral triangle. As a rule, the attribute which serves best to 

 identify members of the class is selected as differentia ; all others 

 flowing necessarily from it being regarded as propria. 



Connexion of Proprium with Essence. A more important question is 

 this : By what kind of necessity must an attribute be connected with the 

 specific nature of a thing in order to be and be called a proprium? It 

 must flow from the essence &quot; as effect from cause,&quot; s &quot; by some law of causa 

 tion &quot;. 4 &quot; The connexion of a proprium with the connotation is a necessary 

 one ; that is, its not following would be inconsistent with some law which we 

 regard as part of the constitution either of the universe or of our minds or 

 of both &quot; ; 5 for &quot; propria are attributes which flow from the whole, or part, of 

 the connotation either as effect from cause or as a conclusion from premises &quot;. 

 These answers are apparently meant to convey that the necessity of the con 

 nexion in question must be an absolutely inviolable necessity. That is to say, 

 the proprium &quot; must be not only inseparable in fact but also inseparable in 

 thought &quot; 7 from the specific nature of the thing, and hence from the connota- 



1 &quot;l8io 5 tffrlv & fji^) 5ri\oT /j.fv rb ri -t\v flvai, fj.6vta S v-jrdpxfi KO! 

 yopftrai rov irpdy paras. Olov iSiov avQpcairov rb ypa/x/iOTi/cTjs e?vai Se/fTi/c^v. Ei yap 

 avBpcov6s 4&amp;lt;rn, 7payii/LtaTiK7js $(KTUt6s eVri, Kal et y pap/tar ucrjs 1)KTiic6s tvnv, av6punc6s 

 Itrrtv. Top.) lib., i., c. 4, n. 5. 



a This is mainly true in the mathematical sciences where our concepts are clearly 

 defined and the relations between them clearly seen to be necessary and universal. 

 Since the strict proprium is coextensive with the differentia it will serve equally well 

 to mark off the species. 



8 CLARKE, Logic, p. 173. 4 ibid., p. 174. 5 WELTON, Logic, i., p. 85. 



6 ibid. 7 CLARKE, Logic, p. 183 referring to the differentia. 



6 * 



