The Metaphysics of a Naturalist 
53 
experience and of the light rays gathered by the microscope as 
instances of forces indirectly affecting experience. A momenta 
reflection, however, will convince anyone having the slightest 
familiarity with physiology that the first instance is a case of 
exceedingly round-about affection of consciousness; for the refrac- 
tion in the lense and the phenomena of accommodation in the 
eye are but the first steps in an extraordinarily complicated 
process before the forces can reach the organ where they are said 
to enter consciousness/^ We see then that the organs of sense 
are simply devices for so adjusting the forces of the surrounding 
world that they shall produce definite and specific kinds of 
experience. All scientific apparatus is simply added apparatus 
with which the ingenuity of man has supplemented the original 
natural endowment. 
The organs of special sense are adapted to cause the experi- 
ences that come to us through their mediation to appear exter- 
nalized. Recent experiments show that a person who wears 
glasses so adjusted as to invert the field of vision will soon come 
to see the world as before, right side up, proving that the con- 
ception of position and relation in space is due to a reaction 
between the experiences of the various organs of sense and that 
is it not a direct ^Tntuition. ’’ Experiences which reach conscious- 
ness through other channels do not have this peculiarity of 
external reference and seem to belong more directly to us. This 
distinction is not a primitive one and to a man born blind who 
suddenly receives his sight the visible world seems to rest on the 
eye just as the felt object rests on the finger tip. 
The distinction between subjective and objective arises very 
early and becomes a most important element in psychological 
analysis, but it must not be allowed to prejudice one in the belief 
that there are any kinds of force known to us otherwise than 
the simplest forms of experience are known, i. c., as affections 
of consciousness. Those forms of force which appeal to us 
through the avenue of more than one sense with special constancy 
and acquire the element of localization have attained in our 
experience a very special coherence and reality, so that the appear- 
ance of one of the data from a single sense suggests or revives the 
data from the other sense and the feeling of reality remains. This 
reality is thought of apart from the sense data and gives rise to 
the idea of substance or a reality beneath and supporting the 
