p. 125:
Why are the objects of the phenomenal world perceived as before us,
outside of ourselves, even though today everybody knows that they
depend upon processes inside of us, in the central nervous system?
... Many of the greatest physiologists, among them even Helmholtz,
have failed to achieve full clarity on this question. Mach and
Avenarius attempted to lead the scientific world away from the
errors already implicit in the formulation of the paradox. But
either their explanations remain little known, or they did not
sufficiently elucidate the problem. For only a few years ago a
well-known physician raised the question anew: "How is it that
consciousness, which is bound to an organism, relates the changes in
its sense organs to something located outside of itself?" All
attempts to explain this "compulsion to project" appeared useless to
him, for he felt that here is one of the eternal enigmas, related to
the mind-body problem. It seems clear that this contemporary
physician is not alone; rather he represents the majority of natural
scientists.
...
The physical processes between object and sense organ are followed
by further events which are propagated through nerves and nerve
cells as far as certain regions of the brain. Somewhere in these
regions processes take place which are tied to the occurrence of
perception ... Now it would obviously be meaningless to identify
with each other the starting point and such a late or distant phase
of this sequence of events ... If I shoot at a target, nobody will
claim that the hole in the target is the same thing as the revolver
from which the bullet came.
...
We might be tempted to say that parts of the phenomenal world should
not be thought of as localized in any place in the physical world as
a matter of principle, since phenomenal and physical localizations
are incommensurable. ... Let us assume that ... the total phenomenal
world of a person is simply not definitely localizable anywhere in
the physical world ... Then it follows that we may arbitrarily
think of [it] wherever in the physical world it would help our
thinking. ... Now, according to our basic assumption, the totality
of a person's perceptual world is strictly correlated with certain
processes in his central nervous system. It will then simplify our
discussion and our terminology if, in what follows, we ... think of
[it] as being mapped on those brain processes which certainly at
least correspond to them.
p. 91:
I do not believe that ... I need defend the strict distinction
between percepts and physical objects any further. But why is it so
difficult to convince people that this distinction is necessary?
[Perhaps because they] may not yet have been able to discard the
last remnants of naive realism from their philosophy of science. I
admit that this is a hard task for all of us.
p. 94:
It is actually simpler to find authors who commit this error than
people who have recognized it as an error. The mistake was first
corrected a hundred years ago, in 1862, by Ewald Hering - an
extrordinary achievement ... characteristically enough, in his
publication Hering made a pessimistic remark about the chances that
his explanation would be understood by his contemporaries. As a
matter of fact, few ever became acquainted with it during the past
hundred years, and not very many seem to know about it now.
p. 84:
What we call the self is just one more directly
accessible percept ... . When dealing with perception more
in detail we shall find it necessary to distinguish sharply between
the self as a percept and the physical organism in question.
p. 89:
Do we really see physical objects? I like to answer questions of this
kind because only when they are answered wil the conceptual confusions
... finally disappear. When we consider the long chain of events that
connects physical facts in our physical environment with directly
accessible percepts, our answer to this particular question can only
be a clear NO.