The character of Galileo's artistic presentation may best be
judged from an example, illustrating the vigorous assault of
Salviati, the champion of the new theory, and the feeble retorts
of his conservative antagonist:

"Salviati. Let us then begin our discussion with the
consideration that, whatever motion may be attributed to the
earth, yet we, as dwellers upon it, and hence as participators in
its motion, cannot possibly perceive anything of it, presupposing
that we are to consider only earthly things. On the other hand,
it is just as necessary that this same motion belong apparently
to all other bodies and visible objects, which, being separated
from the earth, do not take part in its motion. The correct
method to discover whether one can ascribe motion to the earth,
and what kind of motion, is, therefore, to investigate and
observe whether in bodies outside the earth a perceptible motion
may be discovered which belongs to all alike. Because a movement
which is perceptible only in the moon, for instance, and has
nothing to do with Venus or Jupiter or other stars, cannot
possibly be peculiar to the earth, nor can its seat be anywhere
else than in the moon. Now there is one such universal movement
which controls all others--namely, that which the sun, moon, the
other planets, the fixed stars--in short, the whole universe,
with the single exception of the earth--appears to execute from
east to west in the space of twenty-four hours. This now, as it
appears at the first glance anyway, might just as well be a
motion of the earth alone as of all the rest of the universe with
the exception of the earth, for the same phenomena would result
from either hypothesis. Beginning with the most general, I will
enumerate the reasons which seem to speak in favor of the earth's