II.4. "You Make Me Real" - Externalism For A Wider Perspective
Add to this that NCC cannot be caught by neuroscience alone because of the externalist content
of representations (cf., e.g., Burge, 1986, Davidson, 1993, Davies, 1991, and Dretske, 1995) - or at
least because of some externalistic components. Therefore, even identical brain states could
correspond to different mental states if the environment was different. One might say
consciousness is not in the head, but this seems to be throwing the baby out with the bathwater. It
is enough to recognize that consciousness is not only in the head (or depends not only on it). And
that is because the brain (and mind) is not a closed system. Otherwise reference would be
impossible and I would be trapped in total isolation or even had to assume that solipsism is true.
Mental states heavily depend on information from the body, its ontogeny and phylogeny, its present
and past physical and social environment. There is permanent interaction of an organism with its
surroundings (Hurley, 1998), and it is not possible to individuate conscious states without taking
these (past or present) interactions at least implicitely or tacitely into consideration. Even if I could
study my own NCC with an autocerebroscope (Feigl, 1958, p. 456) together with introspection, by-
passing the problem of other minds (II.2.), my mental contents would still be dependent on external
references including a public language. Hence, given that a form of externalism is true,
consciousness cannot be reduced to brain states alone. (But of course this does not mean that it
could not be ontologically reduced to physical states in general - externalism is a form of naturalism
with a wider scope, cf. III.5.) Therefore, NCC are not sufficient for a naturalistic theory of mind.
II.5. "The Soft Parade" - Nonneuronal Intelligence
Nor are they necessary, because of the possible existence of conscious artificial and
extraterrestrial intelligences. Thus, due to its presumed multiple realizability (cf. Putnam, 1975),
consciousness should be viewed not as a product of neural tissues only. This is of course no
limitation of NCC research, though it restricts philosophical generalizations about the nature of
consciousness. However, although multiple realizability may well rule out a general, uniform mind-
matter reduction, it entails the possibility of locally reducing mental states to physical ones - and
perhaps this is all the reduction we need or could want (cf. Kim, 1996, p. 234). Explanations, and
hence reductions, are domain relative.
III. Neural Correlates And The Mind-Matter Problem
Despite the problems and shortcomings of NCC I have just reviewed, NCC are of some
relevance and importance for the still rather notorious mind-body or mind-brain problem (cf., e.g.,
Kim, 1996, and Rey, 1997, for an introduction), which could be more precisely called the mind-
matter problem, and for various philosophical issues, e.g., the nature of perception, representation,
decision-making, action, consciousness and self-awareness. Neuroscience, among other scientific
disciplines, is now able to suggest experimentally constrained hypotheses of philosophical
relevance. Philosophers cannot speculate fruitfully on these issues in ignorance of the data. On the
other hand, neuroscience becomes necessarily more and more involved with philosophical issues.
Therefore, a transdisciplinary teamwork is required (Churchland, 1986, 1996).
III.1. "Piece Of Mind" - Necessarily Human
In spite of not being necessary for consciousness in general - because of the multiple realizability
of consciousness - NCC reveal features that are necessary at least for behavioral manifestations
of human (or primate or vertebrate?) consciousness and self-awareness (cf. Vaas, 1996). This can
easily be learned from lesion studies, coma, stupor, anaesthesia and the reversible breakdown of
NCC due to epilepsy, transcranial magnetic stimulation or simply dreamless sleep. Furthermore, as
the neuropsychology of vision impairments shows (I.3.), there are even specialized, i.e., somewhat
modular brain areas whose destruction leads to the selective loss of conscious experiences, color
awareness, for example.
III.2. "Soul Kitchen" - Does Mind Matter?