36 DISCOURSE ON THE STUDY 



is chiefly, perhaps entirely, from the other or con- 

 tingent class of events that we gain our notions of 

 cause and effect. From them alone we gather that 

 there are such things as laws of nature. The very 

 idea of a law includes that of contingency. " Si 

 quis mala carmina condidisset, fuste ferito;" if such 

 a case arise, such a course shall be followed, if the 

 match be applied to the gunpowder, it will explode. 

 Every law is a provision for cases which may occur, 

 and has relation to an infinite number of cases that 

 never have occurred, and never will. Now, it is 

 this provision, a priori, for contingencies, this con- 

 templation of possible occurrences, and predis- 

 posal of what shall happen, that impresses us with 

 the notion of a law and a cause. Among all the 

 possible combinations of the fifty or sixty elements 

 which chemistry shows to exist on the earth, it is 

 likely, nay almost certain, that some have never been 

 formed ; that some elements, in some proportions, 

 and under some circumstances, have never yet been 

 placed in relation with one another. Yet no chemist 

 can doubt that it is already fixed what they will do 

 when the case does occur. They will obey certain 

 laws, of which we know nothing at present, but 

 which must be already fixed, or they could not be 

 laws. It is not by habit, or by trial and failure, 

 that they will learn what to do. When the contin- 

 gency occurs, there will be no hesitation, no consult- 

 ation ; their course will at once be decided, and 

 will always be the same if it occur ever so often in 

 succession, or in ever so many places at one and the 

 same instant. This is the perfection of a law, that 

 it includes all possible contingencies, and ensures 



