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REV. J. T. GULICK ON DIVERGENT EVOLUTION 
CHAPTER I. 
The Effects of Selection and Independent Generation 
Contrasted. 
In as far as any theory of evolution fails of giving an explanation 
of divergence of character, in so far it fails of explaining the origin 
of species. This is the crucial test which must decide the strength 
or weakness of every theory that is brought forward to account 
for the derivation of many species from one original species. A 
satisfactory theory will not only point out the conditions on 
which divergence depends, hut will show that these conditions 
are the natural result of causes that are already recognized by 
science as having influence in the organic world, or that are now 
shown to have such influence. 
In the present chapter I shall present some reasons for believing 
that neither “ Natural Selection,” nor “ Sexual Selection,” nor 
“ the Advantage of Divergence of Character,” nor “ Difference 
of External Conditions,” nor all these taken together, nor any 
form of Selection that may be hereafter discovered, is sufficient 
to account for Divergence of Character, but that another factor 
of equal if not superior importance must be recognized. In sub- 
sequent chapters I shall try to trace the causes on which this 
additional factor depends, and to indicate as far as possible the 
laws and relations under which they appear. 
Divergent Evolution not explained by Natural 
Selection. 
Natural Selection is the exclusive generation of certain forms 
through the failure to live and propagate of other kinds that are 
less adapted to the environment. 
In the case of the breeder, no selection avails anything that 
does not result in some degree of exclusion. In the case of 
natural selection, where we are not considering ineffectual inten- 
tions, the selection is measured by the exclusion. Where there 
is no exclusion, there is no selection, and where the exclusion is 
great the selection is severe. Moreover, it is self-evident that there 
can be no crossing between the best fitted that survive and propa- 
gate, and the least fitted that perish without propagating. To this 
extent, therefore, the prevention of crossing is complete. And 
further, it is evident that those whose meagre fitness gives them 
but little opportunity for propagating will have a correspondingly 
