CHAPTER I. 
ORGANIC EVOLUTION NOT IDENTICAL WITH NATURAL 
SELECTION. 
“ Happy is he, who lives to understand 
Not human nature only, but explores 
All natures—to the end that he may find 
The law that governs each ; and where begins 
The union, the partition where, that makes 
Kind and degree among all visible beings : 
The constitutions, powers and faculties 
Which they inherit; 
that do assign 
To every class its station and its office 
Through all the mighty commonwealth of things, 
Up from the creeping plant to sovereign man.” 
—Wordsworth. 
ACCORDING to the doctrine of Organic Evolution, all 
living organisms have become what they now are by a 
process of growth or increase in size ; and by a process of 
development or increase in complexity of structure. The 
argument in favour of Natural Selection as the chief or 
sole law which has dominated this process may be con 
ducted on three distinct lines. We may bring forward 
arguments to show that the process of Organic Evolution 
has taken place, and we may then treat these arguments 
as proofs that Natural Selection has dominated this 
process, but without adding any special evidence to 
show that Natural Selection has been the cause of the 
phenomenon ; or we may adduce evidence to show that