ADVANCEMENT OF LEARNING 217 



digestion, which cannot be rectified by the secondary func 

 tions of nature. 



It was not, therefore, without cause, that many of the 

 ancient philosophers, and some of them eminent in their 

 way, became academics and sceptics, who denied all cer 

 tainty of human knowledge, and held that the understand 

 ing went no further than appearance and probability. It is 

 true, some are of opinion that Socrates, when he declared 

 himself certain of nothing, did it only in the way of irony, 

 and put on the dissimulation of knowledge, that, by re 

 nouncing what he certainly knew, he might be thought to 

 know what he was ignorant of. Nor in the latter academy, 

 which Cicero followed, was this opinion held with much 

 reality; but those who excelled in eloquence, commonly 

 chose this sect as the fittest for their purpose, viz., acquir 

 ing the reputation of disputing copiously on both sides of 

 the question, thus leaving the high road of truth for private 

 walks of pleasure. Yet it is certain there were some few, 

 both in the old and new academies, but more among the 

 sceptics, who held this principle of doubting in simplicity 

 and sincerity of heart. But their chief error lay in accusing 

 the perceptions of the senses, and thus plucked up the 

 sciences by their roots. For though the senses often de 

 ceive or fail us, yet, when industriously assisted, they may 

 suffice for the sciences, and this not so much by the help of 

 instruments, which also have their use, as of such experi 

 ments as may furnish more subtile objects than are per 

 ceivable by sense. But they should rather have charged 

 the defects of this kind upon the errors and obstinacy of 

 the mind, which refuses to obey the nature of things; and 

 again, upon corrupt demonstrations, and wrong ways of 

 arguing and concluding, erroneously inferred from the per 

 ceptions of sense. And this we say, not to detract from 

 the human mind, or as if the work were to be deserted, bat 

 that proper assistances may be procured and administered 

 to the understanding, whereby to conquer the difficulties of 

 things and the obscurities of nature. What we endeavor 

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