518 ADDITIONS, 



Lim to ascend towards perfection, easy to glide downwards to false- 

 hoods and vanities : let him then not boast of his wisdom, or extol his 

 knowledge. What he knows is little and worthless, in respect of that 

 which he believes without knowing ; and still less, in respect of that 

 which he is ignorant of. He is mad who thinks highly of his wisdom ; 

 he most mad, who exhibits it as something to be wondered at.' He 

 adds, as another reason for humility, that he has proved by trial, ho 

 could teach in one year, to a poor boy, the marrow of all that the most 

 diligent person could acquire in forty years' laborious and expensive 

 study. 



" To proceed somewhat more in detail with regard to Roger Bacon's 

 views of a Reform in Scientific Inquiry, we may observe that by making 

 Mathematics and Experiment the two great points of his recommenda- 

 tion, he directed his improvement to the two essential parts of all 

 knowledge, Ideas and Facts, and thus took the course which the most 

 enlightened philosophy would have suggested. He did not urge the 

 prosecution of 'experiment, to the comparative neglect of tho existing 

 mathematical sciences and conceptions ; a fault which there is some 

 ground for ascribing to his great namesake and successor, Francis 

 Bacon : still less did he content himself with a mere protest against 

 the authority of the schools, and a vague demand for change, which 

 was almost all that was done by those who put themselves foiward as 

 reformers in the intermediate time. Roger Bacon holds h ; s way 

 steadily between the two poles of human knowledge ; which, as we 

 have seen, it is far from easy to do. 'There are two modes of know- 

 ing,' says he; 15 'by argument, and by experiment. Argument con- 

 cludes a question ; but it does not make us feel certain, or acquiesce 

 in the contemplation of truth, except the truth be also found to be so 

 by experience.' It is not easy to express more decidedly the clearly 

 seen union of exact conceptions with certain facts, which, as we have 

 explained, constitutes real knowledge. 



" One large division of the Opus Majus is ' On the Usefulness of 

 Mathematics,' which is shown by a copious enumeration of existing 

 branches of knowledge, as Chronology, Geography, the Calendar, and 

 (in a separate Part) Optics. There is a chapter, 16 in which it is proved 



15 Op. Muj. p. 445 ; see also p. 443. " Scientise alise sciunt sua principia invenire 

 per experimenta, sed conclusiones per argumenta facta ex principiis inventis. Si 

 vero debeant habere experientiam conclusionum suarum particularem et coznpletam, 

 .unc oportet quod habeant.pcr adjutorium istius scientife nobilis (experimentalis)." 



Ib. p. r,i.>. 



