VERBAL AND REAL PROPOSITIONS. 93 



predication and that of the syllogism, consist of essential propositions. 

 They were usually taken either from the branches or from the main trunk 

 of the Predicaraental Tree, which included nothing but what was oi the es- 

 sence of the species : Omne corpus est substantia, Omne animal est corpus, 

 ' Omnis homo est corpus, Omnis homo est animal, Omnis homo est rationalis, 

 and so forth. It is far from wonderful that the syllogistic art should have 

 been thought to be of no use in assisting correct reasoning, when almost 

 the only propositions which, in the hands of its professed teachers, it was 

 employed to prove, were such as every one assented to without proof the 

 moment he comprehended the meaning of the words ; and stood exactly 

 on a level, in point of evidence, with the premises from which they were 

 drawn, I have, therefore, throughout this work, avoided the employment 

 of essential propositions as examples, except where the nature of the prin- 

 ciple to be illustrated specifically required them. 



§ 5. With respect to propositions which do convey information — which 

 assert something of a Thing, under a name that does not already presup- 

 pose what is about to be asserted ; there are two different aspects in which 

 these, or rather such of them as are general propositions, may be consid- 

 ered : we may either look at them as portions of speculative truth, or as 

 memoranda for practical use. According as we consider propositions in 

 one or the other of these lights, their import may be conveniently expressed 

 in one or in the other of two formulas. 



According to the formula which we have hitherto employed, and which 

 is best adapted to express the import of the proposition as a portion of 

 our. theoretical knowledge. All men are mortal, means that the attributes 

 of man are always accompanied by the attribute mortality : No men are 

 gods, means that the attributes of man are never accompanied by the at- 

 tributes, or at least never by all the attributes, signified by the word god. 

 But when the proposition is considered as a memorandum for practical use, 

 we shall find a different mode of expressing the same meaning better adapt- 

 ed to indicate the office which the proposition performs. The practical use 

 of a proposition is, to apprise or remind us what we have to expect, in any 

 individual case which comes within the assertion contained in the proposi- 

 tion. In reference to this purpose, the proposition, All men are mortal, 

 means that the attributes of man are evidence of, are a mark of, mortality ; 

 an indication by which the presence of that attribute is made manifest. 

 No men are gods, means that the attributes of man are a mark or evidence 

 that some or all of the attributes understood to belong to a god are not 

 there ; that where the foi'mer are, we need not expect to find the latter. 



These two forms of expression are at bottom equivalent; but the one 

 points the attention more directly to what a proposition means, the latter 

 to the manner in which it is to be used. 



Now it is to be observed that Reasoning (the subject to which we are 

 next to proceed) is a process into which propositions enter not as ultimate 

 results, but as means to the establishment of other propositions. We may 

 expect, therefore, that the mode of exhibiting the import of a general prop- 

 osition which shows it in its application to practical use, will best express 

 the function which propositions perform in Reasoning. And accordingly, 

 in the theory of Reasoning, the mode of viewing the subject which consid- 

 ers a Proposition as asserting that one fact or phenomenon is a mark or ev- 

 idence of another fact or phenomenon, will be found almost indispensable. 

 For the purposes of that Theory, the best mode of defining the import of 



