160 ADVANCEMENT OF LEARNING 



tance, would have it remain a doubt forever, and engage 

 themselves in doubting as well as asserting; whereas the 

 true use of wit is to render doubtful things certain, and not 

 certain ones doubtful. And therefore I set down as want 

 ing a calendar of doubts or problems in nature, and recom 

 mend it to be undertaken, with care to blot out daily, as 

 knowledge increases, those that are clearly discussed and 

 settled. And this calendar we would have attended with 

 another of no less utility; for as in every inquiry there are 

 things plainly true, things doubtful, and things plainly false, 

 it were exceeding proper that along with a calendar of doubts 

 should go a calendar of falsehoods and vulgar errors, both in 

 natural history and opinions, that they may no longer dis 

 turb the sciences. 



As to the opinions of the ancient philosophers, for ex 

 ample those of Pythagoras, Philolaus, Xenophanes, Anax- 

 agoras, Parmenides, Leucippus, Democritus, and others, 

 which men usually pass slightly over, it is proper to cast 

 a modest eye upon them. For though Aristotle, after the 

 Ottoman manner, thought he could not reign secure with 

 out putting all his brethren to death, yet those who do not 

 affect dominion and rule, but the inquiry and illustration of 

 truth, will find their account in beholding, at one view, the 

 different opinions of different philosophers, as to the nature 

 of things. But there is no room to expect any pure truth 

 from these or the like theories: for as the celestial appear 

 ances are solved both upon the suppositions of Ptolemy and 

 Copernicus; so common experience, and the obvious face 

 of things, may be applied to many different theories: while 

 a much stricter procedure is required in the right discovery 

 of truth. For as Aristotle accurately remarks, that children, 

 when they first begin to speak, call every woman mother; 

 but afterward learn to distinguish their own: 14 so a childish 

 experience calls every philosophy its mother, but when 

 grown up, will easily distinguish its true one. In the mean- 



14 Aristotle s Physics. 



