H THE PROGRESS OF SCIENCE 97 



abundant analogies suggestive of the conception 

 of a corresponding method of cosmic evolution 

 from a formless " chaos " . to an ordered world 

 which might either continue for ever or undergo 

 dissolution into its elements before starting on 

 a new course of evolution. It is therefore no 

 wonder that, from the days of the Ionian 

 school onwards, the view that the universe was 

 the result of such a process should have maintained 

 itself as a leading dogma of philosophy. The 

 emanistic theories which played so great a part in 

 Neoplatonic philosophy and in Gnostic theology 

 are forms of evolution. In the seventeenth century, 

 Descartes propounded a scheme of evolution, as an 

 hypothesis of what might have been the mode of 

 origin of the world, while professing to accept the 

 ecclesiastical scheme of creation, as an account of 

 that which actually was its manner of coming 

 into existence. In the eighteenth century, Kant 

 put forth a remarkable speculation as to the 

 origin of the solar system, closely similar to that 

 subsequently adopted by Laplace and destined to 

 become famous under the title of the "nebular 

 hypothesis." 



The careful observations and the acute reason- 

 ings of the Italian geologists of the seventeenth 

 and eighteenth centuries; the speculations of 

 Leibnitz in the " Protogsea " and of Buffon in his 

 "Theorie de la Terre;" the sober and profound 

 reasonings of Hutton, in the latter part of the 



VOL. I. H 



