Explaining the nature of consciousness is one of the most important and
perplexing areas of philosophy, but the concept is notoriously ambiguous. The
abstract noun “consciousness” is not frequently used by itself in the
contemporary literature, but is originally derived from the Latin con (with)
and scire (to know). Perhaps the most commonly used contemporary notion of a
conscious mental state is captured by Thomas Nagel’s famous “what it is like”
sense (Nagel 1974). When I am in a conscious mental state, there is something
it is like for me to be in that state from the subjective or first-person point
of view. But how are we to understand this? For instance, how is the conscious
mental state related to the body? Can consciousness be explained in terms of
brain activity? What makes a mental state be a conscious mental state? The
problem of consciousness is arguably the most central issue in current
philosophy of mind and is also importantly related to major traditional topics
in metaphysics, such as the possibility of immortality and the belief in free
will. This article focuses on Western theories and conceptions of
consciousness, especially as found in contemporary analytic philosophy of mind.
The two broad, traditional and competing theories of mind are dualism
and materialism (or physicalism). While there are many versions of each, the
former generally holds that the conscious mind or a conscious mental state is
non-physical in some sense, whereas the latter holds that, to put it crudely,
the mind is the brain, or is caused by neural activity. It is against this
general backdrop that many answers to the above questions are formulated and
developed. There are also many familiar objections to both materialism and
dualism. For example, it is often said that materialism cannot truly explain
just how or why some brain states are conscious, and that there is an important
“explanatory gap” between mind and matter. On the other hand, dualism faces the
problem of explaining how a non-physical substance or mental state can causally
interact with the physical body.
Some philosophers attempt to explain consciousness directly in
neurophysiological or physical terms, while others offer cognitive theories of
consciousness whereby conscious mental states are reduced to some kind of
representational relation between mental states and the world. There are a
number of such representational theories of consciousness currently on the
market, including higher-order theories which hold that what makes a mental
state conscious is that the subject is aware of it in some sense. The
relationship between consciousness and science is also central in much current
theorizing on this topic: How does the brain “bind together” various sensory
inputs to produce a unified subjective experience? What are the neural
correlates of consciousness? What can be learned from abnormal psychology which
might help us to understand normal consciousness? To what extent are animal
minds different from human minds? Could an appropriately programmed machine be
conscious?
The Metaphysics of
Consciousness: Materialism vs. Dualism
Metaphysics is the branch of philosophy concerned with the ultimate
nature of reality. There are two broad traditional and competing metaphysical
views concerning the nature of the mind and conscious mental states: dualism and
materialism. While there are many versions of each, the former generally holds
that the conscious mind or a conscious mental state is non-physical in some
sense. On the other hand, materialists hold that the mind is the brain, or,
more accurately, that conscious mental activity is identical with neural
activity. It is important to recognize that by non-physical, dualists do not
merely mean “not visible to the naked eye.” Many physical things fit this
description, such as the atoms which make up the air in a typical room. For
something to be non-physical, it must literally be outside the realm of
physics; that is, not in space at all and undetectable in principle by the
instruments of physics. It is equally important to recognize that the category
“physical” is broader than the category “material.” Materialists are called
such because there is the tendency to view the brain, a material thing, as the
most likely physical candidate to identify with the mind. However, something
might be physical but not material in this sense, such as an electromagnetic or
energy field. One might therefore instead be a “physicalist” in some broader
sense and still not a dualist. Thus, to say that the mind is non-physical is to
say something much stronger than that it is non-material. Dualists, then, tend
to believe that conscious mental states or minds are radically different from
anything in the physical world at all.
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