DESIGN IN NATUEE 247 



meteorites, which are moving rapidly in all direc- 

 tions, but are unable to escape from the cloud, gradu- 

 ally changing, by mechanical laws, into a sun with 

 its attendant planets. But we cannot imagine how 

 the action of any mechanical causes could clothe one 

 of those planets with vegetation, fill that vegetation 

 with various kinds of animal life, and, at last, give 

 rise to a being with sufficient intelligence to ask how 

 and why it was all done. The idea that physical 

 forces, called into existence indiscriminately and 

 without any ulterior object, could, by their inter- 

 action, evolve the earth and all that is on it, is evi- 

 dently quite incredible. But this general statement- 

 leaves only a vague impression on the mind ; and, in 

 order to clear our ideas, I will give two examples, 

 one taken from inorganic, the other from organic 

 nature, and treat them in some detail. 



In the first place, let us consider the formation of 

 the earth itself. It is evident that no organic de- 

 velopment of importance can ever take place on 

 the sun. For when it has cooled sufficiently to make 

 the formation of protoplasm possible, the tempera- 

 ture of its surface will be rapidly reduced to a point 

 below which protoplasm could not live, so that there 

 would be no time for life to develop. From this we 

 learn that biological evolution can only proceed on a 

 cool body, the surface temperature of which is kept 

 nearly equable by radiation from another hot body. 

 As these conditions must last for a long time, the hot 

 body must be large and at a proper distance from the 

 cool body. But much more than this is required for 

 the development of life. If living organisms were 



