PHYSICAL SCIENCE IN THE MIDDLE AGES. 519 



by reason, that all science requires mathematics. And the arguments 

 which are used to establish this doctrine, show a most just apprecia- 

 tion of the office of mathematics in science. They are such as fol- 

 ] ows : That other sciences use examples taken from mathematics as 

 the most evident : That mathematical knowledge is, as it were, innate 

 to us, on which point he refers to the well-known dialogue of Plato, 

 as quoted by Cicero: That this science, being the easiest, offers the 

 best introduction to the more difficult : That in mathematics, things 

 as known to us are identical with things as known to nature : That 

 we can here entirely avoid doubt and error, and obtain certainty 

 and truth: That mathematics is prior to other sciences in nature, 

 because it takes cognizance of quantity, which is apprehended by in- 

 tuition (intuitu intellectus). 'Moreover,' he adds, 17 'there have been 

 found famous men, as Robert, bishop of Lincoln, and Brother Adam 

 Marshman (de Marisco), and many others, who by the power of math- 

 ematics have been able to explain the causes of things ; as may be 

 seen in the writings of these men, for instance, concerning the Rainbow 

 and Comets, and the generation of heat, and climates, and the celestial 

 bodies.' 



" But undoubtedly the most remarkable portion of the Opus Ma jus 

 is the Sixth and last Part, which is entitled 'De Scientia experimentali.' 

 It is indeed an extraordinary circumstance to find a writer of the thir- 

 teenth century, not only recognizing experiment as one source of 

 knowledge, but urging its claims as something far more important 

 than men had yet been aware of, exemplifying its value by striking 

 and just examples, and speaking of its authority with a dignity of dic- 

 tion which sounds like a foremurmur of the Baconian sentences uttered 

 nearly four hundred years later. Yet this is the character of what we 

 here find. 13 'Experimental science, the sole mistress of speculative 

 sciences, has three great Prerogatives among other parts of knowledge : 

 First she tests by experiment the noblest conclusions of all other 

 sciences : Next she discovers respecting the notions which other 

 sciences deal with, magnificent truths to which these sciences of them- 

 selves can by no means attain : her Third dignity is, that she by her 

 own power and without respect of other sciences, investigates the secrets 

 of nature.' 



*' Op. Jfaj. p. 64. 



is " Veritates magnificas in terminis aliarum scientiarum in quas per nullan. viam 

 oossunt illae scientue, hajc sola scientiarum domina spcculativarum, potest dare." 

 Oa. Maj. p. 465. 



