wind or something else, it is necessary in the first place to be

supported upon one of one's own members which is at rest and so to

push, and in the second place for this member, either itself, or

that of which it is a part, to remain at rest, fixing itself against

something external to itself. Now the man who is himself in the

boat, if he pushes, fixing himself against the boat, very naturally

does not move the boat, because what he pushes against should properly

remain at rest. Now what he is trying to move, and what he is fixing

himself against is in his case the same. If, however, he pushes or

pulls from outside he does move it, for the ground is no part of the

boat.

3



Here we may ask the difficult question whether if something moves

the whole heavens this mover must be immovable, and moreover be no

part of the heavens, nor in the heavens. For either it is moved itself

and moves the heavens, in which case it must touch something immovable

in order to create movement, and then this is no part of that which

creates movement; or if the mover is from the first immovable it

will equally be no part of that which is moved. In this point at least

they argue correctly who say that as the Sphere is carried round in

a circle no single part remains still, for then either the whole would

necessarily stand still or its continuity be torn asunder; but they

argue less well in supposing that the poles have a certain force,

though conceived as having no magnitude, but as merely termini or

points. For besides the fact that no such things have any

substantial existence it is impossible for a single movement to be

initiated by what is twofold; and yet they make the poles two. From

a review of these difficulties we may conclude that there is something

so related to the whole of Nature, as the earth is to animals and

things moved by them.

And the mythologists with their fable of Atlas setting his feet upon