DISCOURSE ON METHOD. 45 



in all that exists or takes place in the world : and 

 farther, by considering the concatenation of these 

 laws, it appears to me that I have discovered many 

 truths more useful and more important than all I \s 

 \ had before learned, or even had expected to learn. 

 V But because I have essayed to expound the chief 

 of these discoveries in a Treatise which certain con- 

 siderations prevent me from publishing, I cannot 

 make the results known more conveniently than by 

 here giving a summary of the contents of this 

 Treatise. It was my design to comprise in it all 

 that, before I set myself to write it, I thought I 

 knew of the nature of material objects. But like 

 the painters who, finding themselves unable to rep- 

 resent equally well on a plain surface all the differ- 

 ent faces of a solid body, select one of the chief, on 

 which alone they make the light fall, and throwing 

 the rest into the shade, allow them to appear only in 

 so far as they can be seen while looking at the prin- 

 cipal one ; so, fearing lest I should not be able to 

 comprise in my discourse all that was in my mind, I 

 resolved to expound singly, though at considerable 

 length, my opinions regarding light; then to take 

 the opportunity of adding something on the sun and 

 the fixed stars, since light almost wholly proceeds 

 from them ; on the heavens, since they transmit it ; 

 on the planets, comets, and earth, since they reflect 

 it; and particularly on all the bodies that are upon 

 the earth, since they are either coloured, or trans- 

 parent, or luminous ; and finally on man, since he is 

 the spectator of these objects. Further, to enable 

 me to cast this variety of subjects somewhat into the 



