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External Qualities and perceptual computation: comment on the reduction of the question of perceptual qualia to a question of physical qualities
It is sometimes
claimed that the phenomenal qualities of perception might in theory
exist not only in the subjective mind but in physical reality as well,
or even that they would not really exist as properties of consciousness
but exclusively as external properties of the material world. In this
short essay I will show why these claims are baseless if we accept the
existence of neurological computation of perceptual stimuli in our
nervous system Qualities The irreducible
phenomenal qualitative aspects of perception of for example vision and
audition would, according to some theorists, also be real, objective
and irreducible (non-quantitative) aspects of the physical objects
perceived. They would not only be secondary qualities in the mind, but
also occur in matter itself. Neurological computation Most materialists and
dualists endorse a theory of sensory perception which includes
neurological computation of sensory stimuli. By computation I mean that
the incoming stimuli are exclusively broken down to their quantitative,
mathematical properties and that the subjective percept is somehow the
phenomenal end-product (integrated by an immaterial self or only by the
brain itself) of neurological 'calculations' applied to those
quantitative properties. Qualities and computation If we accept that in
sensory perception there is always computational processing of stimuli
going on, we also have to accept that if there are really external
non-quantitative qualities in the outside world, one never has any
direct access to them in normal perception. This creates a serious
problem for the theory of external qualities. Even if there were
external non-quantitative qualities in the physical world, neurological
perceptual computation must simply ignore them. This is because
neurological computation can only work with quantitative aspects of
patterns of stimuli which can be processed computationally. Any
non-quantitative aspects that matter might have are simply outside the
reach of sensory perception as sensory perception always works with the
neurological computation of stimuli. The justification of the assumption of external qualities The normal empirical
reason to assume that there are external qualities is based on our
sensory perception. We would normally see or hear such supposed
external material qualities. However, we have just concluded that
normal sensory perception cannot be based on a direct perception of
external qualities. Instead, it is always based on the exclusively
quantitative computation of quantitative properties of matter. In other
words, the qualia of (sensory) perceptual consciousness cannot in any
way be based on the processing of any possible non-quantitative
qualities in the physical world. Therefore, the so called empirical,
normal reason to believe in external qualities is unfounded. If we still wished to
believe in external qualities, we would have to believe in something
for which we can by definition have no sensory evidence whatsoever.
Moreover, the normal reason for which people believe in external
qualities in the physical world is precisely their sensory perception
of them. If there are external qualities in the physical world, we have absolutely no reason to believe that those hypothetical qualities correspond to the ones we find in our perceptual consciousness. Counter-arguments A way out of our
conclusion might seem that we'd simply reject the neurological part of
perception. Although neurology seems to be important for normal
perception, we would choose to ignore its data. Of course, this is
possible, but only if we reject all other empirical, scientific data
concerning physical reality as well, as it is arbitrary (and therefore
irrational) to limit our rejection to neurological data. There is only
one reasonable way to do so, namely ontological idealism. However,
ontological idealism is a theory which cannot be
reconciled with a concept of external non-quantitative qualities
either, because it rejects the existence of a non-subjective matter
altogether. I can still think of the following additional counter-arguments against my line of reasoning: The analysis holds only within a theory of non-reducible qualia. A reductionistic theory of qualia sees qualia as nothing but a level of abstraction of purely
quantitative cerebral processes. Thus, if the external qualities are
broken down to quantitative patterns, we can still have an adequate
perception of those external qualities, because there really is no
difference between quantitative patterns and qualia. However, my
analysis explicitly takes place within a non-reductive theory and
rejects the concept of qualia as mere higher levels of abstraction of exclusively
quantitative patterns. The possible existence of qualia or external
qualities in any other sense is simply another, unrelated issue. Extra-sensory perception of the physical world is also reported to include qualia. This may be the most
sophisticated counter-argument. Due to their remarkable results,
empirical studies that indicate the operation of so called
Extra-Sensory Perception (ESP), for example so called Ganzfeld-studies
or Remote-Viewing Experiments, are more and more being taken seriously
by main-stream scientists and philosophers. Such
studies seem to show that there are subjective perceptions of the
outside world which use neither the physical senses nor neurological
computation and are characterised by similar qualia as normal, sensory
perception. However, we already know from normal
perception that qualia are intrinsically part of this form of
perception, rather than a part of the physical world itself.
Therefore, if we see ESP as a form of perception, we can in principle
expect it to possess identical or at least similar qualitative
dimensions as normal perception while such dimensions per se don't need
to refer to any external qualities. In other words, ESP cannot possibly
give us any compelling, conclusive reasons to believe in qualitative
aspects of matter either. Moreover, we already
know that the qualities perceived in normal perception aren�t real
properties of the external world, but only of our own mind as a result
of interaction with quantitative patterns of the physical world.
Therefore, we would have to postulate an exact parallel of this process
of the creation of qualitative patterns from quantitative patterns in
the physical world if we would want to uphold external qualities in
relation to possible Extra-Sensory Perception of those qualities. Just
as qualia are not part of the physical brain but of the mind,
postulated qualities would not exist in the same way as quantitative
patterns of matter (as they are irreducible to such patterns), but
instead emerge from them in a separate non-quantitative qualitative
"physical" realm (see footnote). Even if this picture of matter were
true, it is altogether different from the one the proponents of
external qualities believe in on the basis of their normal perception. Conclusion The normal reason for
postulating irreducible qualitative aspects of the physical world is
based on our irreducible qualitative perception of that world. However,
if we accept the role of neurological computation in normal perception,
this normal reason should be rejected. Counter-arguments certainly
cannot rehabilitate the normal reason for believing in external
qualities. Besides, the only (possibly) tenable version about external
qualities in the physical world or matter, i.e. emergence of a separate
qualitative dimension within matter which might be perceived directly
in ESP, is completely different from the straight-forward, "normal"
version in which qualitative aspects of the material world would be
quite unproblematically perceived in normal perception. Moreover, postulating
external qualities would not at all solve the qualia part of the
mind-body problem. It would rather create an additional
ontological problem, which cannot be reduced to the problem of
subjective qualia, namely how postulated (non-subjective) qualitative
properties of matter would relate to (and interact with) its
quantitative properties. Summing up, as long as it is not strictly
necessary to postulate external qualities there cannot be any good
reason for doing so. The normal reason should be seen as disqualified. Footnote: One
might wish to claim that the postulated external qualities are not only
irreducible to quantitative patterns in the physical world but even
completely unrelated. However, if there were no relation between
quantitative patterns and external qualities, it would be completely
impossible that the subjective qualia of normal perception created on
the basis of the information of the quantitative patterns computed by
neurology are similar, let alone identical to the postulated external
qualities. Therefore, if there are external qualities they simply must
be intimately related to quantitative properties of matter.
A few other theoretical papers in English by Titus Rivas - Exit Epiphenomenalism: The Demolition of a Refuge - The Causally Efficacious Psyche - Why the efficacy of consciousness cannot be limited to the mind - Kant's Error and its Consequences for the Philosophy of Mind - The Denial of Consciousness in Non-Human Animals - The Survivalist Interpretation of Recent Studies into the Near-Death Experience - A few remarks on the supposed death of dualism - Reincarnation Research: in Search of the Most Parsimonious Exhaustive Hypothesis Contact: titusrivas@hotmail.com |