90 PREFACE TO 



reasons improbable. The Opus Majus was not printed until 

 the eighteenth century, and it is unlikely that Francis Bacon 

 would have taken the trouble of reading it, or any part of it, 

 in manuscript. 1 In the first place there is no evidence in any 

 part of his works of this kind of research, and in the second 

 he had no high opinion of his namesake, of whom he has spoken 

 with far less respect than he deserves. The only work of 

 Roger Bacon's which there is any good reason for believing 

 that he was acquainted with is a tract on the art of prolonging 

 life, which was published at Paris in 1542, and of which an 

 English translation appeared in 1617. The general resemblance 

 between the spirit in which the two Bacons speak of science 

 and of its improvement is, notwithstanding what has sometimes 

 been said, but slight. Both no doubt complain that sufficient 

 attention has not been paid to observation and experiment, but 

 that is all ; and these complaints may be found in the writings 

 of many other men, especially in the time of Francis Bacon. 

 Nothing is more clear than that the essential doctrines of his 

 philosophy among which that of idols is to be reckoned 

 are, so far as he was aware, altogether his own. There is more- 

 over but little analogy between his idols and his namesake's 

 hindrances to knowledge. The principle of classification is alto- 

 gether different, and the notion of a real connexion between 

 the two was probably suggested simply by there being the 

 same number of idols as of hindrances. 2 It is therefore well 

 to remark that in the early form of the doctrine of idols there 

 were only three. In the Partis secundce Delineatio the idols 

 wherewith the mind is beset are said to be of three kinds : they 

 either are inherent and innate or adscititious ; and if the latter, 

 arise either from received opinions in philosophy or from 



1 I can hardly think that he would have omitted to look into a work like the 

 Opus Majus, if he had had the opportunity. But it is very probable that no copy of 

 it was procurable ; possible that he did not even know of its existence. The manner in 

 which he speaks of Roger Bacon in the Temporis Partns Masculus, as belonging to the 

 " utile genus " of experimentalists, " qui de theoriis non admodum soliciti mechanicd 

 quddam subtilitate rerum inventarum extensiones prdiendunt" seems rather to imply 

 that he knew of him at that time chiefly by his reputation for mechanical inventions. 

 J. S. 



2 That the two may be the more conveniently compared, I have quoted Ro- 

 ger Bacon's exposition of his " offendicula," in a note upon the 39th aphorism, in 

 which the names of the four " Idols " first occur. How slight the resemblance is 

 between the two may be ascertained by a very simple test. If you are already 

 acquainted with Francis Bacon's classification, try to assign each of the "offendi- 

 cula " to its proper class. If not, try by the help of Roger's classification to find out 

 Francis's. /. S. 



