v THE PHILOSOPHY OF BIRDS’ NESTS 117 
to be washed away by a heavy rain and their young ones 
destroyed. 
Conclusion 
A fair consideration of all these facts will, I think, fully 
support the statement with which I commenced, and show 
that the chief mental faculties exhibited by birds in the con- 
struction of their nests are the same in kind as those mani- 
fested by mankind in the formation of their dwellings. These 
are, essentially, imitation, and a slow and partial adaptation 
to new conditions. To compare the work of birds with the 
highest manifestations of human art and science is totally 
beside the question. I do not maintain that birds are gifted 
with reasoning faculties at all approaching in variety and 
extent to those of man. I simply hold that the phenomena 
presented by their mode of building their nests, when fairly 
compared with those exhibited by the great mass of mankind 
in building their houses, indicate no essential difference in the 
kind or nature of the mental faculties employed. If instinct 
means anything, it means the capacity to perform some com- 
plex act without teaching or experience. It implies. not only 
innate ideas but innate knowledge of a very definite kind, and, 
if established, would overthrow Mr. Mill’s sensationalism and 
all the modern philosophy of experience. That the existence 
of true instinct may be established in other cases is not 
impossible ; but in the particular instance of birds’ nests, which 
is usually considered one of its strongholds, I cannot find a 
particle of evidence to show the existence of anything beyond 
those lower reasoning and imitative powers which animals 
are universally admitted to possess. 
