MOVEMENT OF ANIMAES, i.-ii. 



upon which it will move both as an integral whole 

 and in its several parts. 



II. Any quality of rest, however, in an animal is of 

 no effect unless there is something outside it which is 

 absolutely at rest and immovable. And it is worth 

 while to stop and consider this dictum ; for the re- 

 flection which it involves applies not merely to animals, 

 but also to the motion and progression of the universe. 

 For just as in the animal there must be something 

 which is immovable if it is to have any motion, so 

 a fortiori there must be something which is immov- 

 able outside the animal, supported upon which that 

 which is moved moves. For if that which supports 

 the animal is to be always giving way (as it does when 

 mice walk upon loose soil " and when persons walk on 

 sand), there will be no progress, that is, no walking, 

 unless the ground were to remain still, and no flying 

 or swimming unless the air or sea were to offer resist- 

 ance. And that which offers resistance must be other 

 than that which is moved, the whole other than the 

 whole, and that which is thus immovable must form 

 no part of that which is moved ; otherwise the latter 

 will not move. This contention is supported by the 

 problem : Why can a man easily move a boat from 

 outside if he thrusts it along with a pole by pushing 

 against the mast or some other part of the boat, 

 but if he tries to do this when he is in the boat 

 itself, Tityus could not move it nor Boreas by blow- 

 ing from inside it, if he really blew as the artists 



than likely that the comparison is with a mouse trying to 

 walk upon a heap of corn. Farquharson emends iv ttj yy to 

 eV Trj ^€1$, which would bear this meaning:. (The form ^erj, 

 cp. Petrie Pap. ii. p. 69 (3rd cent, b.c), would be nearer to the 

 MS. reading.) Diels' suggestion of fiu'>aiv for fivatu is in- 

 genious, but does not give the required sense. 



41.5 



