DESIGN VERSUS NECESSITY. 71 



not doubt that a pump was designed to raise water by 

 the moving of the handle. Of course, the conviction 

 is the stronger, or at least the sooner arrived at, where 

 we can imitate the arrangement, and ourselves produce 

 the result at will, as we could with a pump, and also 

 with the billiard-balls. 



And here I would suggest that your billiard-table, 

 with the case of collision, answers well to a machine. 

 In both a result is produced by indirection — by apply- 

 ing a force out of line of the ultimate direction. And, 

 as I should feel as confident that a man intended to 

 raise water who was working a pump-handle, as if he 

 were bringing it up in pailfuls from below by means 

 of a ladder, so, after due examination of the billiard- 

 table and its appurtenances, I should probably think 

 it likely that the effect of the rebound was expected 

 and intended no less than that of the immediate im- 

 pulse. And a similar inspection of arrangements and 

 results in Nature would raise at least an equal pre- 

 sumption of design. 



You allow that the rebound might have been in- 

 tended, but you require proof that it was. We agree 

 that a single such instance affords no evidence either 

 way. But how would it be if you saw the men doing 

 the same thing over and over ? and if they varied it 

 by other arrangements of the balls or of the blow, and 

 these were followed by analogous results? How if 

 you at length discovered a profitable end of the opera- 

 tion, say the winning of a wager ? So in the coun- 

 terpart case of natural selection : must we not infer 

 intention from the arrangements and the results? 

 But I will take another case of the very same sort, 



