in the depths of which so many stars are fixed so enduringly that
they are kept revolving evenly in spite of such difference of
motion without changing their respective positions. Or if,
according to the much more probable theory, the heavens are
fluid, and every star describes an orbit of its own, according to
what law then, or for what reason, are their orbits so arranged
that, when looked at from the earth, they appear to be contained
in one single sphere? To attain this it seems to me much easier
and more convenient to make them motionless instead of moving,
just as the paving-stones on the market-place, for instance,
remain in order more easily than the swarms of children running
about on them.

"Finally, the seventh difficulty: If we attribute the daily
rotation to the higher region of the heavens, we should have to
endow it with force and power sufficient to carry with it the
innumerable host of the fixed stars --every one a body of very
great compass and much larger than the earth--and all the
planets, although the latter, like the earth, move naturally in
an opposite direction. In the midst of all this the little earth,
single and alone, would obstinately and wilfully withstand such
force--a supposition which, it appears to me, has much against
it. I could also not explain why the earth, a freely poised body,
balancing itself about its centre, and surrounded on all sides by
a fluid medium, should not be affected by the universal rotation.
Such difficulties, however, do not confront us if we attribute
motion to the earth--such a small, insignificant body in
comparison with the whole universe, and which for that very
reason cannot exercise any power over the latter.