S. E. MEZES MAN AND OTHEK ANIMALS. 
27 
by a man with a very different turn of mind, by no less an authority 
than Kant. As a result of many years of thought, probably unparalel- 
led in patience, he declares that the very heart and essence of human 
reason is unity of apperception, by which he means self-consciousness, 
the “I think,” the “think is,” or, in other words, reflective assurance, 
or knowing what one is saying. 
So far then there will be little difficulty and no dispute. Roughly, 
speech differentiates man from other animals; but for speech judgment 
is indispensable, while in turn self-consciousness is essential to judg- 
ment, and accordingly turns out to be the differencing feature reduced 
to its lowest terms. The essentially human power is not the ability 
to use signs that others understand, but the ability to use them know- 
ing what one is about, i. e., knowing that one is using signs , and signi- 
fying to others that things are so and so. 
So far analysis has advanced. But I believe it is now prepared to 
take another step forward, and I venture to make the suggestion in view 
of the unification it will give, if well founded, to our conception of the 
totality of differences between man and other animals. 
The further advance is made when an answer is found to the ques- 
tion, Of what are we conscious when conscious of self? Recent analyses 
of self-consciousness have thrown much light on this problem, and its 
importance will justify a few words of consideration. 
There is no concern here with any conception of a “trancendent” self; 
whether or not any such unexperienced entity exists, its conception, like 
any other, must ultimately rest on, and spring from, some group of ex- 
periences. And our present business consists in suggesting and de- 
scribing those experiences. Anticipating what will appear presently, 
those experiences can be indicated in a word: When conscious of self 
one is always conscious of voluntary actions-. The evidence for this 
statement may be grouped under two heads, pathology and moral re- 
sponsibility. 
Ordinarily the best way of indicating the objects designated by any 
name is to point them out. When that resource is not available, as hap- 
pens in this case, the next best means is to discover the objects whose 
changes are spontaneously regarded as changes in the class of objects 
to be defined, for the former will be among the constituent elements 
sought. When the heart stops, death supervenes, and consequently life 
consists, among other things, and in some animals, in the beating of 
the heart. When the piston-rod is broken, the engine is “killed,” and 
consequently the piston-rod is argued to be an essential part of an en- 
gine. And a similar line of considerations will suggest the constituents 
of the self; moreover the records of pathology furnish many instances of 
the diseases of personality. 
