If I ask you to leave these vain questions, I will not expect you to try and find out the earth’s point of support.  The mind would reel on beholding its reasonings losing themselves without end.  Do you say that the earth reposes on a bed of air? cf. Arist., De Cœlo. ii. 13, 16.  ᾽Αναξιμένης δὲ καὶ ᾽Αναξάγο ρας καὶ Δημόκριτος τὸ πλάτος αἴτιον εἶναί φασι τοῦ μένειν αὐτήν· οὐ γὰρ τέμνειν ἀλλ᾽ ἐπιπωματίζειν (covers like a lid) τὸν ἀ& 153·ρα τὸν κάτωθεν, ὅπερ φαίνεται τὰ πλάτος ἔχοντα τῶν σωματων ποιεῖν  How, then, can this soft substance, without consistency, resist the enormous weight which presses upon it?  How is it that it does not slip away in all directions, to avoid the sinking weight, and to spread itself over the mass which overwhelms it?  Do you suppose that water is the foundation of the earth? The theory of Thales.  cf. note on Letter viii. 2 and Arist., De Cœlo. ii. 13, 13 where he speaks of Thales describing the earth floating like wood on water.  You will then always have to ask yourself how it is that so heavy and opaque a body does not pass through the water; how a mass of such a weight is held up by a nature weaker than itself.  Then you must seek a base for the waters, and you will be in much difficulty to say upon what the water itself rests.