144 
EASTMAN. 
With the material universe this method was completely 
changed. The ancient Philosopher found himself confronted 
with the earth, the sun, the moon, the planets and the almost 
countless number of the stellar systems; he recognized the 
unspoken challenge to solve their mysteries, and took refuge 
in feeble speculation. He had penetrated the depths of the 
human passions, but the distance to the earth’s nearest 
neighbor was unknown; he had probed the follies and set 
the bounds to the ambitions of his fellow-men, but he had 
no conception of the form and motion of the earth or of the 
order of the universe. 
Undaunted by the lack of knowledge, and confident that 
intellectual acumen, though unsupported by observed facts, 
was equal to the demands of any problem, he explained the 
system of the universe on the basis of his crude hypotheses, 
and felt no need of any criterion by which his speculations 
could be tested. In all these schools of Philosophy assum¬ 
ing to deal with the problems of the physical world, there was 
one common element, one peculiar arrangement, that evi¬ 
dently was deemed essential to the stability of every system. 
In every scheme some member of the system was placed in 
the center, and represented the immovable nucleus of the 
universe. It was of little importance what body was given 
the place of honor; whether it be sun, earth, or fire, immov¬ 
able stability was the distinguishing attribute of the central 
figure in all the systems, from the earliest known, down 
through the Ptolemaic to the Copernican. It was the one 
fixed idea in the order of the solar system that survived the 
clashing of rival hypotheses for more than twenty-five cen¬ 
turies, and had apparently passed with success the test which 
observation mercilessly claims the right to apply to theory. 
The idea of an immovable center of the solar system had 
its origin in vague hypotheses, untrammeled by perplexing 
facts, and it triumphantly passed all tests of theory and ob¬ 
servation down to the beginning of the eighteenth century. 
In 1718 Edmund Halley, 1 afterwards Astronomer Royal 
1 Halley, Edmund. Philosophical Transactions, 1718; 736. 
