ON THE FACTORS OF EVOLUTION IN LANGUAGE. 245 
the ascending scale of life, like those of insects already men- 
tioned, are unconscious. ‘The full development of mind, as 
found in man, consists in the union and interpenetration of 
these three elements,—namely, Consciousness, Intelligence, 
and Will. But among animals, especially among the higher 
domestic animals, there is much development of mind which 
is not merely unconscious and instinctive, but evidently 
conscious. Many dogs manifest a degree of mental power 
which probably marks the highest that can be attained by any 
being without the faculty of abstraction and language, and 
astonishes us by its near approach to our own. It is altogether 
misleading to lump together all the mental powers of animals 
under the name of instincts. It not only explains nothing, 
but it suggests what is certainly untrue,—namely, that the 
most intelligent actions of the highest animals inferior to man 
are performed like those of many insects, without the guidance 
of conscious purpose. These remarks may be scarcely rele- 
vant, yet I think it worth while to make them, because the 
intelligence of animals is so mysterious and difficult a subject, 
that there is a great temptation for systematic writers to set 
it aside and pass it by, as Prof. Max Miiller for the most part 
has done. 
The conclusions at which we have aimed are the 
following :— 
1. The stages in the evolution of thought are not simul- 
taneous, but, as in all evolution, successive. They are thus 
enumerated :— 
Sensation. 
Perception, 
Formation of generalized mental images. 
Abstraction with conception. 
The last is the distinctively human power. It depends on 
the power of directing thought at will, and its result and 
product is language. 
2. Language is related to thought as organization is to the 
bodily life. Organization is the result of life, and language 
of thought; organization reacts on life, heightening its 
efficiency, and language on thought, heightening its efficiency. 
But organization does not exist at the origin of life, nor 
language at the origin of thought. As in vital evolution 
there are two factors; on the one hand, the organizing intelli- 
gence which produces organic adaptation and guides evolution, 
and, on the other hand, hereditary habit or the principle of 
permanence, in virtue of which organisms on the whole re- 
semble their parents ;—so in language there are two factors ; 
