42 DERIVATION OF THE LAWS. [CHAP. III. 



PROPOSITION I. 



4. To deduce the laws of the symbols of Logic from a conside- 

 ration of those operations of the mind which are implied in the strict 

 use of language as an instrument of reasoning. 



In every discourse, whether of the mind conversing with its 

 own thoughts, or of the individual in his intercourse with others, 

 there is an assumed or expressed limit within which the subjects of 

 its operation are confined. The most unfettered discourse is that 

 in which the words we use are understood in the widest possible 

 application, and for them the limits of discourse are co-extensive 

 with those of the universe itself. But more usually we confine our- 

 selves to a less spacious field. Sometimes, in discoursing of men 

 we imply (without expressing the limitation) that it is of men 

 only under certain circumstances and conditions that we speak, 

 as of civilized men, or of men in the vigour of life, or of men 

 under some other condition or relation. Now, whatever may be 

 the extent of the field within which all the objects of our dis- 

 course are found, that field may properly be termed the universe 

 of discourse. 



5. Furthermore, this universe of discourse is in the strictest 

 sense the ultimate subject of the discourse. The office of any name 

 or descriptive term employed under the limitations supposed is not 

 to raise in the mind the conception of all the beings or objects to 

 which that name or description is applicable, but only of those 

 which exist within the supposed universe of discourse. If that 

 universe of discourse is the actual universe of things, which it 

 always is when our words are taken in their real and literal sense, 

 then by men we mean all men that exist ; but if the universe of 

 discourse is limited by any antecedent implied understanding, 

 then it is of men under the limitation thus introduced that we 

 speak. It is in both cases the business of the word men to direct 

 a certain operation of the mind t by which, from the proper uni- 

 verse of discourse, we select or fix upon the individuals signified. 



6. Exactly of the same kind is the mental operation implied 

 by the use of an adjective. Let, for instance, the universe of dis- 

 course be the actual Universe. Then, as the word men directs 



