76 THE HISTORY OF CREATION. 
himself, and about the origin of the world around him, the 
natural theories of development, on the other hand, are 
necessarily of much more recent origin. These views are 
met with only among nations of a more matured civilization, 
to whom, by philosophic culture, the necessity of a know- 
ledge of natural causes has become apparent; and even among | 
these, only individual and specially gifted natures can be 
expected to have recognized the origin of the world of 
phenomena, as well as its course of development, as the 
necessary consequences of mechanical, naturally active 
causes. In no nation have these preliminary conditions, for 
the origin of a natural theory .of development, ever existed 
in so high a degree as among the Greeks of classic antiquity. 
But, on the other hand, they lacked a close acquaintance 
with the facts of the processes and forms of nature, and, 
consequently, the foundation baséd upon experience, for a 
satisfactory unravelling of the problem of development. 
Exact investigation of nature, and the knowledge of nature 
founded on an experimental basis, was of course almost 
unknown to antiquity, as well as to the Middle Ages, and 
is only an acquisition of modern times. We have ther ant 
here no special occasion to examine the natural theories 
of development of the various Greek philosophers, since 
they were wanting in the knowledge gained by experience, 
both of organic and inorganic nature, and since they 
almost always, as the consequence, lost themselves in airy 
speculations. 
One man only must be mentioned here by way of 
exception,—Aristotle, the greatest and the only truly great 
naturalist of antiquity and the Middle Ages, one of the 
grandest geniuses of all time. To what a degree he stands 
