I
In spite of the elucidations of contemporary realists, a number of
idealists continue to adduce in behalf of idealism certain facts
having an obvious physical nature and explanation. The visible
convergence of the railway tracks, for example, is cited as evidence
that what is seen is a mental "content." Yet this convergence follows
from the physical properties of light and a lens, and is physically
demonstrated in a camera. Is the photograph, then, to be conceived as
a psychical somewhat? That the time of the visibility of a light does
not coincide with the time at which a distant body emitted the light
is employed to support a similar idealistic conclusion, in spite of
the fact that the exact difference in time may be deduced from a
physical property of light--its rate. The dislocation in space of the
light seen and the astronomical star is used as evidence of the mental
nature of the former, though the exact angular difference is a matter
of simple computation from purely physical data. The doubling of
images of, say, the finger when the eyeball is pressed, is frequently
proffered as a clincher. Yet it is a simple matter to take any body
that reflects light, and by a suitable arrangement of lenses to
produce not only two but many images, projected into space. If the
fact that under definite _physical_ conditions (misplacement of
lenses), a finger yields two images proves the psychical character of
the latter, then the fact that under certain conditions a sounding
body yields one or more echoes is, by parity of reasoning, proof that
the echo is made of mental stuff.[59]
If, once more, the differences in form and color of a table to
different observers, occupying different physical positions, is proof
that what each sees is a psychical, private, isolated somewhat, then
the fact that one and the same physical body has different effects
upon, or relations with, different physical media is proof of the
mental nature of these effects. Take a lump of wax and subject it to
the same heat, located at different positions; now the wax is solid,
now liquid--it might even be gaseous. How "psychical" these phenomena!
It almost seems as if the transformation of the physical into the
mental in the cases cited exemplifies an interesting psychological
phenomenon. In each case the beginning is with a real and physical
existence. Taking "the real object," the astronomical star, on the
basis of its physical reality, the idealist concludes to a psychical
object, radically different! Taking the _single_ object, the finger,
from the premise of its real singleness, he concludes to a double
mental content, which then takes the place of the original single
thing! Taking one-and-the-same-object, the table, presenting _its_
different surfaces and reflections of light to different real
organisms, he eliminates the one-table-in-its-different-relations in
behalf of a multiplicity of totally separate psychical tables! The
logic reminds us of the story of the countryman who, after gazing at
the giraffe, remarked, "There ain't no such animal." It almost seems,
I repeat, as if this self-contradiction in the argument creates in
some minds the impression that the object--not the argument--is
undergoing the extraordinary reversal of form.
However this may be, the problem indicated in the foregoing cases is
simply the good old problem of the many in one, or, less cryptically,
the problem of the maintenance of a continuity of process throughout
differences. I do not pretend that this situation, though the most
familiar thing in life, is wholly without difficulties. But its
difficulty is not one of epistemology, that is, of the relation of
known to a knower; to take it as such, and then to use it as proof of
the psychical nature of a final term, is also to prove that the trail
the rocket stick leaves behind is psychical, or that the flower which
comes in a continuity of process from a seed is mental.