Chapter VII 
(lntercalated) 
Mr. Spencer’s “The Factors of Organic Evolution” 
INCE the foregoing and several of the succeeding 
chapters were written, Mr. Herbert Spencer has made 
his position at once more clear and more widely understood 
by his articles “‘ The Factors of Organic Evolution ” which 
appeared in the Nineteenth Century for April and May, 
1886. The present appears the fittest place in which to 
intercalate remarks concerning them. 
Mr. Spencer asks whether those are right who regard 
Mr. Charles Darwin’s theory of natural selection as by 
itself sufficient to account for organic evolution. 
“On critically examining the evidence’’ (modern 
writers never examine evidence, they always “‘ critically,” 
or “carefully,” or ‘“‘ patiently,” examine it), he writes, 
“‘ we shall find reason to think that it by no means explains 
all that has to be explained. Omitting for the present any 
consideration of a factor which may be considered primor- 
dial, it may be contended that one of the factors alleged by 
Erasmus Darwin and Lamarck must be recognised as a 
co-operator. Unless that increase of a part resulting from 
extra activity, and that decrease of it resulting from 
inactivity, are transmissible to descendants, we are without 
a key to many phenomena of organic evolution. Udterly 
inadequate to explain the major part of the facts as is the 
hypothesis of the inheritance of functionally produced modifica- 
tions, yet there is a minor part of the facts very extensive 
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