KANT AND EVOLUTION 547 



author's death, the " Protogsea " of Leibniz was published. In this 

 Leibniz contended, on grounds now familiar enough, that the earth 

 must have originally been in a fluid and intensely heated state; that 

 through the cooling of the surface a solid crust was formed and the 

 viscous fiery substance of the globe concentrated in the interior; that 

 the present earth-structure is due to the successive action in the past 

 of fire (fusion) and water (sedimentation) ; and that the existence of 

 fossils testifies to the extinction of once flourishing species of animals, 

 in consequence of modifications of the earth's surface due to one or the 

 other of these agencies. 



For comparison with the hypotheses of his precursors and succes- 

 sors, Kant's own scheme of cosmogony must now be indicated in its 

 more essential features. He assumes for a starting point a " state of 

 nature which is the very simplest that could follow upon nonentity," 

 namely, a chaos in which all the matter in the universe was scattered 

 throughout infinite space. It somehow " filled " the whole of that 

 space, and yet its component particles were infinitely more diffused than 

 now ; Kant expressly declares that space was once " full," and is now 

 <e empty," except for the actual celestial bodies. The original particles 

 were not all alike ; they differed in " specific density and force of 

 attraction." Consequently, when the universe is once permitted to be- 

 gin active business, " the scattered elements of the denser sort, by virtue 

 of their attraction, gather together out of the space surrounding them 

 all the matter of less specific gravity; these elements in turn, with the 

 material which has united with them, collect in points where the par- 

 ticles of a yet denser kind are found " ; and so on. 



If we follow in imagination this process by which nature fashions itself 

 into form throughout the whole extent of chaos, we easily perceive that the 

 sole result of this process would consist finally in the agglomeration of divers 

 masses which, when their formation was complete, would be forever at rest 

 and unmoved. 



Fortunately, nature has other forces at her command ; besides gravi- 

 tation, there is also operative a force of repulsion, which shows itself 

 <e especially when matter is decomposed into fine particles." By this 

 force the elements, " as they fall towards the attracting body are de- 

 flected by one another and have their perpendicular fall converted into 

 a movement of revolution." Having indicated the two general working 

 principles of his cosmical mechanics, Kant now judiciously leaves the 

 problem of the genesis of a universe, and turns somewhat abruptly to 

 the simpler problem of the formation of our solar system, from the 

 solution of which " we shall be able by analogy to infer a similar mode 

 of origination in the case of the larger world-systems." 



The lesser process, as Kant conceives it, may be said to fall into 

 four stages: (1) The formation of the nucleus of a sun. There is 

 formed at the point of maximum attraction of a given region of space, 

 " a body which, so to say, grows from an infinitely small germ, at first 



