De Defectu Oraculorum
Plutarch
Plutarch. Moralia, Vol. V. Babbitt, Frank Cole, translator. Cambridge, MA: Harvard University Press; London: William Heinemann Ltd., 1936 (printing).
Having spoken at this length, I stopped. Philip, after no long interval, said, That the truth about these matters is thus or otherwise is not for me to assert. But if we eliminate the god from one world, there is the question why we make him the creator of only five worlds and no more, and what is the relation of this number to the great mass of numbers; and I feel that I would rather gain a knowledge of this than of the meaning of the E[*](The meaning is discussed in the second essay of this volume.) dedicated here. For the number five represents neither a triangle nor a square, nor is it a perfect number nor a cube, nor does it seem to present any
other subtlety for those who love and admire such speculations. Its derivation from the number of elements, at which the Master[*](Presumably Pythagoras, but possibly Plato.) hinted darkly, is in every way hard to grasp and gives no clear intimation of the plausibility which must have drawn him on to assert that it is likely that when five bodies with equal angles and equal sides and enclosed by equal areas are engendered in matter the same number of worlds should at once be perfected from them.