Chap. II. 
MENTAL POWEKS. 
35 
organic being excepting man bad possessed any mental 
power, or if bis powers bad been of a wholly different 
nature from those of the lower animals, then we should 
never have been able to convince ourselves that our 
high faculties had been gradually developed. But it 
can be clearly shewn that there is no fundamental 
difference of this kind. We must also admit that 
there is a much wider interval in mental power be- 
tween one of the lowest fishes, as a lamprey or lancelet, 
and one of the higher apes, than between an ape and 
man ; yet this immense interval is filled up by number- 
less gradations. 
Nor is the difference slight in moral disposition 
between a barbarian, such as the man described by the 
old navigator Byron, who dashed his child on the rocks 
for dropping a basket of sea-urchins, and a Howard or 
Clarkson ; and in intellect, between a savage who does 
not use any abstract terms, and a Newton cr Shakspeare. 
Differences of this kind between the highest men of the 
highest races and the lowest savages, are connected by 
the finest gradations. Therefore it is possible that they 
might pass and be developed into each other. 
My object in this chapter is solely to shew that there 
is no fundamental difference between man and the 
higher mammals in their mental faculties. Each divi- 
sion of the subject might have been extended into a 
separate essay, but must here be treated briefly. As 
no classification of the mental powers has been univer- 
sally accepted, I shall arrange my remarks in the order 
most convenient for my purpose ; and will select those 
facts which have most struck me, with the hope that 
they may produce some effect on the reader. 
With respect to animals very low in the scale, I shall 
have to give some additional facts under Sexual Selec- 
tion, shewing that their mental powers are higher than 
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