APPENDIX A 



has the best claim to the name, is the dptdfios of the 

 circular movement (ij kvkXw <t>opd), because the apidfios of 

 this even, imiform, circular revolution is " most cogniz- 

 able " (^23 b). And as everything is measured by some 

 standard which is cognate to it {e.g., horses are measured 

 or counted by the unit " a horse," see 220 h and 223 b), 

 so time is measured by " a time," viz., by a determinate 

 length of time ; and the time taken by the sphere of the 

 universe to revolve is the " measure " par excellence : 

 all other movements are measured by that movement, 

 and time too is measured by that movement (c/. De 

 caelo II. 287 a 23 ff., Phys. VIII. 265 b 8 ff.). Hence 

 human affairs and all other things which have a natural 

 movement and yev^ais and <l>dopa are spoken of as being 

 a " cycle " : they are all discriminated by time, and 

 their beginning and their end occur as it were according 

 to some " period " (223 b). And further, since a move- 

 ment may be the same over and over again, so too may 

 time, e.ff., year, spring, autumn (220 b 12). 

 (14) O. ^ C. II. 338 a 1 ff. If a thing's " being " is " neces- reV«<ris 

 sary " {i.e., absolutely necessary ; see Introd. §§ 7-9), cyclical. 

 then it is eternal (dt'Stoj) ; and if it is eternal, then its 

 " being " is " necessary." " And also, if a thing's ycVe- 

 cris is " necessary," then its yiveais is eternal ; and if 

 its yevems is eternal, " necessary." Thus, if a thing's 

 yfveais is absolutely, not conditionally, " necessary," its 

 yev€<Tis must of necessity be cyclical and return upon 

 itself {avaKVKXeiv kox dvaKa^TTTeiv) . [Proof of this. — 

 YevfOLs must be either limited or not limited. We agree 

 it not limited. If it is not limited, it must be either 

 rectilinear or cyclical. If it is to be eternal, it cannot be 

 rectilinear ; hence it must be cyclical.] Thus it is in 

 circular movement and in circular yeveais that we find 

 absolute necessity. This fits in with the doctrine (proved 

 on other and independent grounds) that circular move- 

 ment {i.e., the movement of the Heavens) is eternal ; for 

 it is the movements which belong to this eternal move- 

 ment, and the movements which are caused by it, which 

 yCvovrai. and elaiv " of necessit}'." That which is moving 

 round in a circle is always setting other things in move- 

 ment, so that their movement too must be circular. 



" Eternal being and eternal ycW<rt« are mentioned at G.A. 742 b 27, 31. 



573 



