Strength of Darwin’s Position 
The man in the street, then, was able to com- 
prehend the theory of natural selection. This 
was greatly in its favour. Men are usually well 
disposed towards doctrines which they can readily 
understand. 
The nineteenth century was a superficial age. 
It liked simplicity in all things. If Darwin could 
show that natural selection was capable of pro- 
ducing one species, men were not only ready but 
eager to believe that it could explain the whole 
of organic evolution. 
The simplicity of the Darwinian theory has its 
evil side. It has undoubtedly tended to make 
modern biologists superficial in their methods. 
It has, indeed, stimulated the imagination of 
men of science; but the stimulation has not in 
all cases been a healthy one. 
So far from adhering to the sound rule laid 
down by Pasteur, ‘(never advance anything 
that cannot be proved in a simple and decisive 
manner,” many modern naturalists allow their 
imagination to run riot, and so formulate ill- 
considered theories, and build up hypotheses on 
the most insecure foundations. “A tiny islet of 
truth,” writes Archdale Reid, ‘is discovered, on 
which are built tremendous and totally illegitimate 
hypotheses.” 
Another source of Darwin’s strength was the 
vast store of knowledge he had accumulated. 
For twenty years he had been steadily amassing 
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