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possible for anything otherwise to be a cause, and 

 also inferring, that, from this opinion, they might 

 be led to disbelieve in the existence of Providence ; 

 wishing likewise to inculcate this dogma, that the 

 world is governed by Providence, he tacitly mani- 

 fests it to those who are abundantly able to under- 

 stand that the world is unbegotten according to 

 time ; but to those who are not able to understand 

 this, he indicates that it is generated. He is also 

 anxious that they may believe this, in order that 

 at the same time they may be persuaded in the 

 existence of Providence. But the second cause 

 which induced Plato thus to write, is this, that 

 assertions are then more clear, when we meet with 

 them as with things which actually take place. 

 Thus geometricians compose diagrams as if they 

 were generated, though they are not composites. 

 And Euclid defines a circle, as being more simple, 

 to be a plane figure, comprehended under one 

 line, to which all lines falling from one point 

 within the figure are equal to each other. But 

 wishing to explain a sphere, he defines it, as if it 

 was among the number of things generated, to be 

 formed by the revolution of a semi-circle about the 

 diameter, until it returns to the same point from 

 which it began to be moved. If, however, he had 

 intended to explain the sphere which already ex- 

 isted, he would have defined it to be a solid figure, 



