Modern Science : A Criticism 



a time when the earth was the centre of the universe, 

 and the sun a ball of fire revolving round it. In 

 those times men could predict with certainty that 

 the sun would rise next morning, and could even 

 name the hour of its appearance ; but we do not 

 therefore think that their theories were true. 

 When Adams and Leverrier foretold the appear- 

 ance of Neptune in a certain part of the sky, they 

 made a brief prediction to an unknown planet 

 from the observed relations of the movements of 

 the known planets ; that does not show, however, 

 that the grand generalisation of these movements, 

 called the " law of gravitation," is correct. It 

 merely shows that it did well enough for this very 

 brief step — brief indeed compared with the real 

 problems of Astronomy, for which latter it is 

 probably quite inadequate. 



Tycho Brahe, excellent astronomer as he was, 

 kept as we saw to the epicycle theory. He imagined 

 that the moon's path round the earth was a fixed 

 combination of cycle and epicycle. Kepler in- 

 troduced the conception of the ellipse. Later 

 on the motion of the perigee and other deviations 

 compelled the abandonment of the ellipse and the 

 supposition of an endless curve, similar to an ellipse 

 at any one point, and maintaining a fixed mean 

 distance from the earth, but never returning on 

 itself or making a definite closed figure of any 

 kind. Finally the researches of Mr. George 

 Darwin have destroyed the conception of the fixed 

 mean distance, and introduced that of a continually 

 enlarging spiral. Certainly no four theories could 



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