778 PHILOSOPHICAL THOUGHT. 



exists as the felt continuity of consciousness, of what 

 Kant termed the " unity of apperception." We are thus 

 led back again to that revolution of thought which 

 Kant, more than a century ago, compared to the Coper- 

 40. nican revolution in astronomy. The comparison implied 



Illustration 



attitude g b * * n Cant's words suggests a picture by which I may hope 

 a picture. to ma k e the position more comprehensible to my readers. 

 Suppose that on a clear but perfectly dark night we 

 glance at the starry firmament with that wonder which 

 Kant expressed in one of the most majestic passages of 

 his writings : suppose that we are so lost in admiration 

 that we forget entirely our own existence and presence. 

 We may assume that this was the state of mind 

 which, thousands of years ago, led the first astronomers 

 to their observations. What probably arrested their 

 attention in this firmament of the Heavens was the 

 fixed stars, their constellations and their regular move- 

 ment. Next to them the moon, the planets, and the 

 sun, in their changing positions among the unchangeable 

 and ever-recurring constellations of the fixed stars. In 

 course of time these prominent objects in the firmament 

 were found to present certain constant features which 

 were described by what are termed Kepler's Laws of 

 Planetary Motion, and brought together by Galileo and 

 Newton in the science of physical or gravitational 

 astronomy. At a much later and comparatively recent 

 stage of astronomical research other phenomena of the 

 Heavens, such as the Nebulae, the Meteorites, or the more 

 proximate meteorological phenomena in cloudland, were 

 added to physical astronomy. Still more recently the 

 invention of the spectroscope created a new science of 



