GENERATION OF ANIMALS, II. vi. 



with the parts of the body : one is, by nature, prior 

 to another." But the term " prior " at once com- 

 prises a variety of meanings. E.g., take the differ- 

 ence between {a) that for the sake of rvhich a thing 

 is, and (b) that thing which is for its sake : of these, 

 one (6) is prior in point of formation,'' while the 

 other (a) is prior in point of being or reaUty. 

 Further, " that which is for the sake of the End " 

 comprises two divisions : (i) that whence the move- 

 ment is derived and (ii) that which is employed by 

 the End ; or, in other words, (i) something which 

 generates, and (ii) something which serves as an 

 instrument for what is generated. Of the two, 

 the productive factor must exist prior to the other : 

 e.g., a teacher must exist prior to a learner, while 

 pipes are posterior to the person who is learning to 

 play them : it is superfluous for people who cannot 

 play pipes to possess them. So we have these three 

 things : (1) the End, which we describe as being that 

 for the sake of rvhich (other things are) ; (2) the things 

 which are for the sake of the End, .\\z., the activat- 

 ing and generative principle (second, because the 

 existence of that which is productive and generative, 

 qua such, is relative to what it produces and gener- 

 ates) ; (3) the things which are serviceable, which 

 can be and are employed by the End. Thus, first of 

 all there must of necessity exist some part in which 

 the principle of movement resides (for of course 

 this is a part of the End, and the supreme con- 

 trolling part of it) ; after that comes the animal as a 

 whole, i.e., the End '^ ; third and last of all come the 

 parts which serve these ^ as instruments for various 

 employments. If it is true, then, that there is a part 



** Or perhaps " this," referring only to the " End." 



213 



