I o 2 The Advancement of Learning 



thing is extant which cometh the nearest in degree to that 

 impossibiUty ; to the end that by these optatives and 

 potentials man's inquiry may be more awake in deducing 

 direction of works from the speculation of causes: and 

 secondly, that those experiments be not only esteemed 

 which have an immediate and present use, but those princi- 

 pally which are of most universal consequence for inven- 

 tion of other experiments, and those which give most hght 

 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 invention of the sails which give the 

 motion. 



4. Thus have I passed through Natural Philosophy, and the 

 deficiencies 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 canimus surdis, respondent omnia sylvae.* 



The voice of nature will consent, whether the voice of man 

 do or no. And as Alexander Borgia was wont to say of the 

 expedition of the French for Naples, that they came with 

 chalk in their hands to mark up their lodgings, and not with 

 weapons to fight ; so I like better that entry of truth which 

 cometh peaceably, with chalk to mark up those minds 

 which are capable to lodge and harbour it, than that which 

 cometh with pugnacity and contention. ^ 



5. But there remaineth a division of natural philosophy 

 according to the report of the inquiry, and nothing concern- 

 ing the matter or subject ; and that is positive and considera- 

 tive; when the inquiry reporteth either an assertion or a 

 doubt. These doubts or non liquets are of two sorts, parti- 

 cular and total. For the first, we see a good example there- 

 of in Aristotle's Problems, which deserved to have had a 

 better continuance; but so nevertheless as there is one 

 point whereof warning is to be given and taken. The 

 registering of doubts hath two excellent uses : the one, that 

 it saveth philosophy from errors and falsehoods; when 



» Virg. Eel. X. 8. 



' Nov. Org. i. 35. This saying of Alexander VI. was called forth 

 by the expedition of Charles VIII. which overran Italy in about 

 £.ve months, a.d. 1494. 



