REN£ DESCARTES S3 



Archbishop Antonius de Dominis^ before 1611 as the result of 

 observations of glass balls and spherical bottles filled with 

 water; but the agreement of the angle calculated by Descartes 

 with the actual bow was nevertheless an important proof of 

 the correctness of this explanation, and hence of all knowledge 

 connected with it. The colours of the bow were, however, 

 left unexplained by Descartes, and this success remained for 

 Newton, 



Descartes made extensive attempts at the solution of many 

 other further problems, including a new foundation for the 

 mechanics of the heavens. But how little his manner of 

 thought was suited to scientific investigation in a larger way is 

 seen from his condemnation of Galileo, for reasons given in 

 his letters; for example: 'Everything that Galileo says about 

 the philosophy of bodies falling in empty spaces, is built up 

 without any foundation; for he ought first to have determined 

 the nature of weight . . .' To think like this is to put the bridle 

 on the horse of scientific investigation at the wrong end, 

 which all experience has shown to be an unfruitful proceed- 

 ing. In actual fact, the Galilean horse had still to march on 

 with its head in front for a considerable time, to the discovery, 

 observation and interpretation of new facts, in order to 

 approach the question of the nature of weight. The extent 

 to which Descartes' mind was directed towards grasping the 

 non-material side of the world is seen by his filling space with 

 eddies of an unknown substance, whereby the planets were 

 driven around the sun, and also by his widely known con- 

 clusion: Cogito ergo sum (I think, therefore I am), whereby 

 in determining his own existence he is not concerned with 

 the existence of his body, nor with impressions on his senses, 

 but simply with the existence of his mind. 



^ Who perished in 1624 in the prison of the Inquisition. His contribu- 

 tions to the theory of the rainbow were also noted by Newton in his 

 Opticks. 



