CHAPTER IL 
DIFFERENCES OF DEFINITION. 
“We must speak by the card or equivocation will undo us.” 
—Hamlet, Act j, sc. i. 
As the overwhelming majority of scientific men believe 
that Natural Selection occupies, to say the least, a most 
important position in relation to the transmutation of 
species, it might be expected that they would be quite 
agreed as to what Natural Selection is : that they would 
have a very clear and definite notion as to what is 
meant by this term. It is, therefore, with a good deal 
of surprise that we find that “ several scientific men have 
thought the term ‘Natural Selection’ good, because its 
meaning is not obvious.”* Surely it is difficult to con 
ceive of any legitimate advantage which can arise from a 
vague definition and a consequently hazy comprehension 
of the essential and fundamental principles of a scientific 
theory. This is surely not characteristic of the truly 
scientific man, who would scorn by such uncertainty to 
justify the rebuke of the poet— 
“ The Gods laugh in their sleeve 
To watch man doubt and fear, 
Who knows not what to believe 
Since he sees nothing clear, 
And dares stamp nothing false where he finds nothing sure.” 
—(Matthew Arnold. Empedocles on Et/ia.) 
That there has been considerable misapprehension on 
this subject is obvious from the fact that Mr. Romanes 
* The Life and Letters of Charles Darwin, ii., 278.