ADVANCEMENT OF LEARNING. [Book 



use, but those principally which arc of most universal consequence for 

 invention of other experiments, and those which give most light to the 

 invention of causes : for the invention of the mariner s needle, which 

 giveth the direction, is of no less benefit for navigation, than the inven 

 tion of the sails, which give the motion. 



Thus have I passed through natural philosophy, and the deficien 

 cies thereof, wherein if I have differed from the ancient and received 

 doctrines, and thereby shall move contradiction ; for my part as I 

 affect not to dissent, so I purpose not to contend. If it be truth, 

 Non canirr.us surdis, respondent omniasylvro : 



the voice of nature will consent, whether the voice of man do or ro, 

 And as Alexander Borgia was wont to say of the expedition of the 

 French for Naples, that they came with chalk in their hande to mark 

 up their lodgings, and not with weapons to fight : so I 1 ke better that 

 entry of truth, which cometh peaceably with chalk to mark up those 

 minds which arc capable to lodge and harbour it, than that which 

 cometh with pugnacity and contention. 



But there rcmaineth a division of natural philosophy according to 

 the report of the inquiry, and nothing concerning the matter or subject ; 

 and that is positive and considerative ; when the inquiry reporleth 

 either an assertion, or a doubt. These doubts, or non liquets, aie of 

 two sorts, particular, and total. For the first, we see a good example 

 thereof in Aristotle s Problems, which deserved to have had a better con 

 tinuance ; but so nevertheless, as there is one point whereof warning is 

 to be given and taken. The registring of doubts hath two excellent 

 uses : the one, that it saveth philosophy from errors and falsehoods, 

 when that which is not fully appearing is not collected into assertion. 

 whereby error might draw error, but reserved in doubt. The other, 

 that the entry of doubts are as so many suckers or spur.gfrs to draw 

 use of knowledge ; insomuch, as that which, if doubts had nor. preceded, 

 a man should never have advised, but passed it over without note, by 

 the suggestion and solicitation of doubts is made to be attended and 

 applied. But both these commodities do scarcely countervail an in 

 convenience which will intrude itself, if not debarred ; which is, that. 

 when a doubt is once received, men labour rather how -.o keep it a 

 doubt still, than how to solve it, and accordingly bend their wits. Ol 

 this we sec the familiar example in lawyers and scholars, both which. 

 if they have once admitted a doubt, it goeth ever after authorized fi 

 a doubt. But that use of wit and knowledge is to be allowed, which 

 labourcth to make doubtful things certain, and not those which labour to 

 make certain things doubtful. Therefore these kalendars of doubts I 

 commend as excellent things, so that there be this caution used, that when 

 they be thoroughly sifted and brought to resolution, they be from thence 

 forth omitted, discarded , and not continued to cherish and encouragement 

 in doubting. To which kalendar of doubts or problems, I advise to be 

 annexed another kalendar. as much or more material, which is a kalen- 

 clar of popular errors, I mean chiefly in natural history, such as pass 

 in speech and conceit, and are nevertheless detected and convicted of 



