To meet the objection that atoms are invisible, and therefore cannot
exist, Lucretius enumerates many things we cannot see although we know
they exist. No one doubts the existence of winds, heat, cold and
smells; yet no one has seen the wind, or heat, or cold, or a smell.
Clothes become moist when hung near the sea, and dry when spread in
the sunshine; but no one has seen the moisture entering or leaving the
clothes. A pavement trodden by many feet is worn away; but the minute
particles are removed without our eyes being able to see them.

Another objector urges--"You say the atoms are always moving, yet the
things we look at, which you assert to be vast numbers of moving
atoms, are often motionless." Him Lucretius answers by an analogy.
"And herein you need not wonder at this, that though the
first-beginnings of things are all in motion, yet the sum is seen to
rest in supreme repose, unless when a thing exhibits motions with its
individual body. For all the nature of first things lies far away from
our senses, beneath their ken; and, therefore, since they are
themselves beyond what you can see, they must withdraw from sight
their motion as well; and the more so, that the things which we can
see do yet often conceal their motions when a great distance off.
Thus, often, the woolly flocks as they crop the glad pastures on a
hill, creep on whither the grass, jewelled with fresh dew, summons or
invites each, and the lambs, fed to the full, gambol and playfully
butt; all which objects appear to us from a distance to be blended
together, and to rest like a white spot on a green hill. Again, when
mighty legions fill with their movements all parts of the plains,
waging the mimicry of war, the glitter lifts itself up to the sky, and
the whole earth round gleams with brass, and beneath a noise is raised
by the mighty tramplings of men, and the mountains, stricken by the