464 FALLACIES. 



ployed to prove those properties. As well might it 

 be argued that a government is good because we 

 ought to support it, or that there is a God because it 

 is our duty to pray to him. 



It is assumed by all the disputants in the De 

 Finibus as the foundation of the inquiry into the 

 summum bonum, that " sapiens semper beatus est." 

 The idea that wisdom could be consistent with unhap- 

 piness, was always rejected as inadmissible : the 

 reason assigned by one of the interlocutors, near the 

 beginning of the third book, being, that if the wise 

 could be unhappy, there was not much use in pursuing 

 wisdom. But by unhappiness they did not mean 

 pain or suffering ; to that, it was granted that the 

 wisest person was liable in common with others : he 

 was happy, because in possessing wisdom he had the 

 most valuable of possessions, the most to be sought 

 and prized of all things, and to possess the most valu- 

 able thing was to be the most happy. By laying it 

 down, therefore, at the commencement of the inquiry, 

 that the sage must be happy, the disputed question 

 respecting the summum bonum was in fact begged ; 

 with the further assumption, that pain and suffering, 

 so far as they can coexist with wisdom, are not unhap- 

 piness, and are no evil. 



The following are additional instances of Petitio 

 Principii, under more or less of disguise. 



Plato, in the Sophist es, attempts to prove that 

 things may exist which are incorporeal, by the argu- 

 ment that justice and wisdom are incorporeal, and 

 justice and wisdom must be something. Here, if by 

 something be meant, as Plato did in fact mean, a thing 

 capable of existing in and by itself, and not as a 

 quality of some other thing, he begs the question in 

 asserting that justice and wisdom must be something : 



