If our brains were simple, we would be too simple to understand them.
Mario Puzo
The understanding of smart brains and minds requires smart techniques. Within the last decade a
rapid progress of monitoring brain activities with imaging techniques like positron emission
tomography (PET) and functional magnetic resonance imaging (fMRI), with high-resolution electro-
and magnetoencephalography (EEG, MEG), event-related potentials, intracranial multiple-electrode
recording and transcranial magnetic stimulation etc. led to a growing body of evidence that
behavioral activities and mental events - as far as verbal reports and (neuro)psychological test
batteries can tell - are accompanied by certain neural states (see, e.g., Gazzaniga, 1995, for an
introduction). This might count as a support for naturalistic theories of mind, which argue that
consciousness supervenes on or is identical with or is realized or caused by certain brain states
and processes. Let's accept the existence of such neural correlates of consciousness, NCC for
short (please note the plural). We may safely do so at least for the sake of the argument. There is
no need for them to be strictly localized. It is sufficient if they take the form of more or less robust
spatial and/or temporal distributed relations within the nervous system, especially the brain. Some
of these relations may probably be described only in abstract ways of representations, for example,
neuronal network theory, the vector space approach or by order parameters in the framework of
synergetics (cf., e.g., Churchland, 1995, Flohr, 1995, Haken, 1996, and Jirsa and Vaas, 1995). And
even within neurophysiology, we must refer to many different levels of organisation and complexity
- at least from the properties of single molecules on the one hand to the sensomotoric foundations
and control of behavior on the other. Unfortunately, even this rather weak account is not enough for
the more far-reaching and ambitious scientific and philosophical purposes like the understanding of
intentionality, phenomenal awareness (qualia), self- and I-consciousness. On the other hand,
there's more to NCC than meets the sceptic's eye.
Here, I'd like to give a brief sketch of three philosophical issues connected with the scientific
investigation of NCC. I'm afraid that it is possible to go into details only occasionally, because my
main point is trying to survey this diverse field. First, I shall demonstrate how NCC are helpful to
explain properties of our conscious experience contrary to some criticism of neurophilosophy.
Second, I shall review some problems and shortcomings of NCC. Third, I shall illustrate the
relevance and importance but also some limitations of NCC to the still rather notorious mind-body
problem.
I. Neuronal And Phenomenal Features Of Consciousness
Despite the ostensible fundamental difference between our subjective experience and the third
person perspective of science, NCC can address or even explain properties of consciousness. Let
me show three examples for this:
I.1. "Sweet Dreams Are Made Of This" - NCC Meet Phenomenology
NCC help us to explain phenomenal features of consciousness. An interesting example is the
neuropsychology of REM (rapid eye movement) sleep dreaming (for the following see, e.g., Braun
et al., 1998, Hobson, Stickgold, and Place-Schott, 1998, Maquet et al., 1996, Solms, 1997, and
Vaas, 1998). In recent times PET studies have unveiled which brain areas show an increased or
decreased metabolism during dreaming. Of philosophical relevance here is that these findings
provide a deeper understanding of some well-known phenomenal features of dreaming which
consist in a linkage between already known NCC within the awake brain on the one hand and the
recently discovered neural correlates of phenomenal features during dreaming on the other.
This linkage is established in the following way:
• At first we know an already reliable fact of crude NCC, namely that a specific conscious state in
the awake person goes along with a specific brain activity.
• Furthermore, we are familiar with some features of consciousness during REM sleep dreaming
from our first-person perspective (and from the reports of others).