It is, perhaps, difficult for us now to appreciate precisely their position. These doctrines of antiquity, which had come down hoary with age, and the discovery of which had reawakened learning and quickened intellectual life, were accepted less as a science or a philosophy than as a religion. Had they regarded Aristotle as a verbally inspired writer, they could not have received his statements with more unhesitating conviction. In any dispute as to a question of fact, such as the one before us concerning the laws of falling bodies, their method was not to make an experiment, but to turn over the pages of Aristotle; and he who could quote chapter and verse of this great writer was held to settle the question and raise it above the reach of controversy.
It is very necessary for us to realize this state of things clearly, because otherwise the attitude of the learned of those days toward every new discovery seems stupid and almost insane. They had a crystallized system of truth, perfect, symmetrical; it wanted no novelty, no additions; every addition or 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, they went back muttering and discontented to their musty old volumes and their garrets, there to invent occult reasons for denying the validity of the observation, and for referring it to some unknown disturbing cause.
They saw that if they gave way on this one point they would be letting go their anchorage, and henceforward would be liable to drift along with the tide, not knowing whither. They dared not do this. No; they must cling to the old traditions; they could not cast away their rotting ropes and sail out on to the free ocean of God's truth in a spirit of fearless faith.
Yet they had received a shock: as by a breath of fresh salt breeze and a dash of spray in their faces, they had been awakened out of their comfortable lethargy. They felt the approach of a new era. Yes, it was a shock, and they hated the young Galileo for giving it them—hated him with the sullen hatred of men who fight for a lost and dying cause.
We need scarcely blame these men; at least we need not blame them overmuch. To say that they acted as they did is to say that they were human, were narrow-minded, and were the apostles of a lost cause. But they could not know this; they had no experience of the past to guide them; the conditions under which they found themselves were novel, and had to be met for the first time. Conduct which was excusable then would be unpardonable now, in the light of all this experience to guide us. Are there any now who practically repeat their error, and resist new truth? who cling to any old anchorage of dogma, and refuse to rise with the tide of advancing knowledge? There may be some even now.
Well, the unpopularity of Galileo smouldered for a time, until, by another noble imprudence, he managed to offend a semiroyal personage, Giovanni de' Medici, by giving his real opinion, when consulted, about a machine which De' Medici had invented for cleaning out the harbor of Leghorn. He said it was as useless as it in fact turned out to be. Through the influence of the mortified inventor he lost favor at court; and his enemies took advantage of the fact to render his chair untenable. He resigned before his three years were up, and retired to Florence.