211 
VI. 
THE PHILOSOPHY OF BIRDS’ NESTS. 
Instinct or Reason in the Construction of Birds’ Nests. - 
Birps, we are told, build their nests by instinct, while 
man constructs his dwelling by the exercise of reason. 
Birds never change, but continue to build for ever on 
the self-same plan; man alters and improves his houses 
continually. Reason advances ; instinct is stationary. 
This doctrine is so very general that it may almost 
be said to be universally adopted. Men who agree 
on nothing else, accept this as a good explanation of 
the facts. Philosophers and poets, metaphysicians and 
divines, naturalists and the general public, not only 
agree in believing this to be probable, but even adopt 
it as a sort of axiom that is so self-evident as to need 
no proof, and use it as the very foundation of their 
speculations on instinct and reason. A belief so general, 
one would think, must rest on indisputable facts, and 
be a logical deduction from them. Yet I have come to 
the conclusion that not only is it very doubtful, but - 
absolutely erroneous; that it not only deviates widely 
from the truth, but is in almost every particular exactly 
opposed to it. I believe, in short, that birds do not 
build their nests by instinct; that man does not con- 
P2 
