growth was an imperfection, an excrescence,
a deformity. Progress was unnecessary and undesired. The Church had a
rigid system of dogma which must be accepted in its entirety on pain of
being treated as a heretic. Philosophers had a cast-iron system of truth
to match--a system founded upon Aristotle--and so interwoven with the
great theological dogmas that to question one was almost equivalent to
casting doubt upon the other.

In such an atmosphere true science was impossible. The life-blood of
science is growth, expansion, freedom, development. Before it could
appear it must throw off these old shackles of centuries. It must burst
its old skin, and emerge, worn with the struggle, weakly and
unprotected, but free and able to grow and to expand. The conflict was
inevitable, and it was severe. Is it over yet? I fear not quite, though
so nearly as to disturb science hardly at all. Then it was different: it
was terrible. Honor to the men who bore the first shock of the battle!

Now, Aristotle had said that bodies fell at rates depending on their
weight. A five-pound weight would fall five times as quick as a
one-pound weight; a fifty-pound weight fifty times as quick, and so on.
Why he said so nobody knows. He cannot have tried. He was not above
trying experiments, like his smaller disciples; but probably it never
occurred to him to doubt the fact. It seems so natural that a heavy body
should fall quicker than a light one; and perhaps he thought of a stone
and a feather, and was satisfied.

Galileo, however, asserted that the weight did not matter a bit; that
everything fell at the same rate--even a stone and a feather, but for
the resistance of the air--and would reach the ground in the same time.
And he was not content to be pooh-poohed and snubbed. He knew he was
right, and he was determined to make everyone see the facts as he saw
them. So one morning, before the assembled university, he ascended the
famous leaning tower, taking with him a one-hundred-pound shot and a
one-pound shot. He balanced them on the edge of the tower, and let them
drop together. Together they fell, and together they struck the ground.
The simultaneous clang of those two weights sounded the death-knell of
the old system of philosophy, and heralded the birth of the new.

But was the change sudden? Were his opponents convinced? Not a jot.
Though they had seen with their eyes and heard with their ears, the full
light of heaven shining upon them,