DESIGN VERSUS NECESSITY. 63 



balls at the same instant, with like forces, in the direc- 

 tions before given. In this case the balls would not 

 pass as before, namely, the red ball to the south, and 

 the white ball to the west, but they must both meet 

 and strike each other in the centre of the table, and, 

 being perfectly elastic, the red ball must pass to the 

 west pocket, and the white ball to the south pocket. 

 We may suppose that the players acted wholly with- 

 out concert with each other, indeed, they may be 

 ignorant of each other's design, or even of each 

 other's existence ; still we know that the events must 

 happen as herein described. ]STow, the first half of 

 the course of these two balls is from an impulse, or 

 proceeds from a power, acting from design. Each 

 player has the design of driving his ball across the 

 table in a diagonal line to accomplish its lodgment at 

 the opposite corner of the table. Neither designed 

 that his ball should be deflected from that course and 

 pass to another corner of the table. The direction of 

 this second part of the motion must be referred en- 

 tirely to necessity, which directly interferes with the 

 purpose of him who designed the rectilinear direction. 

 We are not, in this case, to go back to find design in 

 the creation of the powers or laws of inertia and 

 elasticity, after the order of which the deflection, at 

 the instant of collision, necessarily takes place. We 

 know that these powers were inherent in the balls, 

 and were not created to answer this special deflection. 

 We are required, by the hypothesis, to confine atten- 

 tion in point of time, from the instant preceding the 

 impact of the balls, to the time of their arrival at the 

 opposite corners of the table. The cues are moved 



