1 6 Ethics and the Natural Sciences. 



theirs, then nothing remains but to point out its 

 unique nature, and inquire finally whether ethics 

 be not less a science than a branch of speculation ? 

 In the meantime, however, we must not forget, 

 and may derive hope from, the current fashion 

 of identifying the science of morals with the 

 sciences of nature. Though mathematical ethics 

 be a vision, who shall say that physical ethics may 

 not become an actuality ? 



The sciences of nature have been classified as 

 deductive or experimental. Originally they were 

 all experimental ; their laws expressing only 

 those particular uniformities which observation 

 and experiment showed to exist, but giving no 

 reasons for their existence. Such an empirical 

 law we have, e.g., in the tendency of hot water 

 to break glass. Now, when the particular em 

 pirical laws of a science can be brought into re 

 lation to more general laws, seen to be special 

 applications of them, and so deducible from them, 

 that science passes from the experimental to the 

 deductive stage. The cracking of glass by hot 

 water, for example, takes its place as a phenom 

 enon of deductive science as soon as it has been 

 shown that heat tends to expand all substances, 

 that the crack is due to the expansion of the 

 heated portion in spite of the adjacent cooler por- 



