236 REASONING. 



true of certain objects, is true of each of those objects. 

 If all ratiocination were no more than the application 

 of this maxim to particular cases, the syllogism would 

 indeed be, what it has so often been declared to be, 

 solemn trifling. The dictum de omni is on a par with 

 another truth, which in its time was also reckoned of 

 great importance, " Whatever is, is ;" and not to be 

 compared in point of significance to the cognate 

 aphorism, "It is impossible for the same thing to be 

 and not to be ;" since this is, at the lowest, equivalent 

 to the logical axiom that contradictory propositions 

 cannot both be true. To give any real meaning to 

 the dictum de omni, we must consider it not as an 

 axiom but as a definition ; we must look upon it as 

 intended to explain, in a circuitous and paraphrastic 

 manner, the meaning of the word class. 



An error which seemed finally refuted and dis- 

 lodged from science, often needs only put on a new 

 suit of phrases, to be welcomed back to its old 

 quarters, and allowed to repose unquestioned for 

 another cycle of ages. Modern philosophers have not 

 been sparing in their contempt for the scholastic 

 dogma that genera and species are a peculiar kind of 

 substances, which general substances beiag the only 

 permanent things, while the individual substances 

 comprehended under them are in a perpetual flux, 

 knowledge, which necessarily imports stability, can 

 only have relation to those general substances or 

 universals, and not to the facts or particulars included 

 under them. Yet, though nominally rejected, this 

 very doctrine, whether disguised under the Abstract 

 Ideas of Locke (whose speculations, however, it has 

 less vitiated than those of perhaps any other writer 

 who has been infected with it), under the ultra-nomi- 

 nalism of Hobbes and Condillac, or the ontology of 



