194 NOVUM ORGANUM 



ural history, since we are forced to have recourse to sup 

 positions for examples, instead of ascertained instances. 



Again, let the required nature be the discursive power 

 of the mind. The classification of human reason and ani 

 mal instinct appears to be perfectly correct. Yet there are 

 some instances of the actions of brutes which seem to show 

 that they, too, can syllogize. Thus it is related, that a 

 crow, which had nearly perished from thirst in a great 

 drought, saw some water in the hollow trunk of a tree, but 

 as it was too narrow for him to get into it, he continued to 

 throw in pebbles, which made the water rise till he could 

 drink; and it afterward became a proverb. 



Again, let the required nature be vision. The classifi 

 cation appears real and certain, which considers light as that 

 which is originally visible, and confers the power of seeing; 

 and color, as being secondarily visible, and not capable of 

 being seen without light, so as to appear a mere image or 

 modification of light. Yet there are instances of alliance in 

 each respect; as in snow when in great quantities, and in 

 the flame of sulphur; the one being a color originally and 

 in itself light, the other a light verging toward color. 68 



XXXVI. In the fourteenth rank of prerogative in 

 stances, we will place the instances of the cross, borrowing 

 our metaphor from the crosses erected where two roads 

 meet, to point out the different directions. We are wont 

 also to call them decisive and judicial instances, and in 

 some cases instances of the oracle and of command. Their 

 nature is as follows: When in investigating any nature the 

 understanding is, as it were, balanced, and uncertain to 

 which of two or more natures the cause of the required 



68 Snow reflects light, but is not a source of light. 



