78 PROGRESS OF SCIENCE. 



fection of undisciplined senses ; IV. Concealment of our own 

 ignorance, become with Francis the Idols of the Theatre, the 

 Idols of the Forum, the Idols of the Tribes, the Idols of the 

 Den. (g) Both men, again, proclaimed Experience to be the 

 sole guide of the scientific pioneer that is, they advocated 

 the study of the physical sciences, subjecting it to reason. 

 " Experimental science," says Roger, " is the mistress of the 

 speculative sciences, and has three prerogatives. First, she 

 tests and verifies the conclusions of the other sciences ; 

 secondly, she discourses on the notions which other sciences 

 deal with magnificent results to which these sciences are in- 

 competent. Thirdly, she investigates the secrets of nature by 

 her own powers." " I call experimental science/'* says he 

 again, " that one which neglects (puts aside) arguing; for the 

 strongest arguments prove nothing so long as conclusions are 

 not verified by experience." " Experimental science does not 

 receive truth from the hand of the superior sciences ; for it is 

 she which is the mistress, and the other sciences are her 

 servants. She has the right to command all the sciences, since 

 alone she certifies and consecrates their results. Experimental 

 science therefore is the queen of sciences and the bound of 

 all speculation." " In all researches," he goes on, " we must 

 use the best possible method. Now this method consists in 

 studying in their necessary order the diverse parts of science, 

 placing in the first rank what should really be found at the 

 beginning : the easiest before the most difficult, the simple 

 before the composite, the general before the particular. We 

 must also choose as a study the most useful objects on account 

 of the brevity of life.f Science must be exhibited with clear- 

 ness and certainty, without mixture of doubt and obscurity. 

 Now all this is impossible without experiment, for we have, 

 indeed, various means of knowing authority, reasoning, 

 experiment; but authority has no value unless it is accounted 

 for (Non sapit nisi detur ejus ratio] ; it does not enable one 

 to understand, it only makes one believe; it imposes itself 

 upon the mind without enlightening it. As to reasoning, 

 sophistry cannot be distinguished from demonstration, except 



* Opus Tertium. 



t Francis Bacon advocated science on utilitarian grounds. 



