I think the best answer is that consciousness and subjectivity is not
the brain or the food but is the activities of the brain.
brain activities extended across time is the self as the film moving
through a movie projector with light shining through is the movie.
the self is a group of ongoing activities;
Functionalism in the philosophy of mind is the doctrine that what
makes something a mental state of a particular type does not depend on
its internal constitution, but rather on the way it functions, or the
role it plays, in the system of which it is a part. This doctrine is
rooted in Aristotle's conception of the soul, and has antecedents in
Hobbes's conception of the mind as a "calculating machine", but it has
become fully articulated (and popularly endorsed) only in the last
third of the 20th century. Though the term 'functionalism' is used to
designate a variety of positions in a variety of other disciplines,
including psychology, sociology, economics, and architecture, this
entry focuses exclusively on functionalism as a philosophical thesis
about the nature of mental states.
http://plato.stanford.edu/entries/functionalism/
William James & Functionalism
Some people disagreed with this reductionist viewpoint. For one,
William James, an American, described consciousness as a stream that
continually changes, and it cannot be reduced to elements. James still
believed that consciousness could be studied, but he was interested in
the functions of consciousness rather than its elements. His focus on
the functions of consciousness was motivated by (a) his pragmatic
philosophy, which means he was interested in the usefulness of things
and ideas rather than their ultimate explanation, and (b) by Darwin's
theory of evolution, which had suggested that every creature's
features had evolved for some purpose. Thus, human consciousness must
have some purpose or function, and James wanted to understand what
that purpose was.
Just as Wundt's ideas led to the development of structuralism, James's
ideas led to the development of functionalism, which was a loose
collection of psychologists who were interested in what the functions
consciousness serves, rather than what is the components or structure
of consciousness.
http://io.uwinnipeg.ca/~epritch1/amdvlop.htm
The term "cognitive psychology" was coined by Ulric Neisser in 1967,
in a book of the same name. It was a name given to an emerging point
of view that bootstrapped off the computer metaphor to describe the
human mind, without relying on it to the point of reducing the human
mind to a computer. Like the rest of materialist science, cognitive
psychology acknowledges that the mind is defined as what the brain
does, and the brain is a purely physical system that operates (albeit
complexly) within the constraints of natural law and the forces of
cause and effect. This view is called causal functionalism or simply,
functionalism.
http://www.wisegeek.com/what-is-cognitive-psychology.htm
Turing (1950) was among the first to note that the human brain could
be analogied to the computer, which has been designed to carry out
certain functions. In particular, whilst computers are physical
devices with electronic substrate that perform computations on inputs
to give outputs, so brains are physical devices with neural substrate
that perform computations on inputs which produce behaviours. While
this comparison may be fictional rather than fundamental it helps show
that functionalism is the theoretical level between the physical
implementation and behavioural output (Marr, 1982). Therefore, it is
different from its predecessors of Cartesian dualism (advocating
discrete mental and physical substances) and Skinnerian behaviourism
and physicalism (declaring only physical substances) because it is
only concerned with the effective functions of the brain, through its
organization or its 'software programs'. More formally, functionalism
says that "mental states are constituted by their causal relations to
one another and to sensory inputs and behavioural outputs" (Block,
1996).
http://en.wikipedia.org/wiki/Functionalism_(psychology)
Functionalism is a theory of the mind in contemporary philosophy,
developed largely as an alternative to both the identity theory of
mind and behaviorism. Its core idea is that mental states (beliefs,
desires, being in pain, etc.) are constituted solely by their
functional role - that is, their causal relations to other mental
states, sensory inputs, and behavioral outputs. Since mental states
are identified by a functional role, they are said to be multiply
realizable; in other words, they are able to be manifested in various
systems, even perhaps computers, so long as the system performs the
appropriate functions. While functionalism has its advantages, there
have been several arguments against it, claiming that it is an
insufficient account of the mind...
...Homuncular functionalism was developed largely by Daniel Dennett
and has been advocated by William Lycan. It arose in response to the
challenges that Ned Block's China Brain (a.k.a. Chinese nation) and
John Searle's Chinese Room thought experiments presented for the more
traditional forms of functionalism (see below under 'Criticism'). In
attempting to overcome the conceptual difficulties that arose from the
idea of a nation full of Chinese people wired together with each one
carrying out the functional or causal role that would normally be
ascribed to the mental states of an individual mind, for example, many
functionalists simply bit the bullet, so to speak, and argued that
such a Chinese nation would indeed possess all of the qualitative and
intentional properties of a mind; i.e. it would become a sort of
systemic or collective mind with propositional attitudes and other
mental characteristics. Whatever the worth of this latter hypothesis,
it was immediately objected that it entailed an unacceptable sort of
mind-mind supervenience: the systemic mind which somehow emerged at
the higher-level must necessarily supervene on the individual minds of
each individual member of the Chinese nation, to stick to Block's
formulation. But this would seem to put into serious doubt, if not
directly contradict, the fundamental idea of the supervenience thesis:
there can be no change in the mental realm without some change in the
underlying physical substratum. This can be easily seen if we label
the set of mental facts that occur at the higher-level M and the set
of mental facts that occur at the lower-level M1. Given the
transitivity of supervenience, if M supervenes on M1 and M1 supervenes
on P (physical base), then M and M1 both supervene on P, even though
they are (allegedly) totally different sets of mental facts.
Since mind-mind supervenience seemed to have become acceptable in
functionalist circles, it seemed to some that the only way to resolve
the puzzle was to postulate the existence of an entire hierarchical
series of mind levels (analogous to homonculi) which became less and
less sophisticated in terms of functional organization and physical
composition all the way down to the level of the physico-mechanical
neuron or group of neurons. The homunculi at each level, on this view,
have authentic mental properties but become simpler and less
intelligent as one works one's way down the hierarchy...
http://en.wikipedia.org/wiki/Functionalism_%%28philosophy_of_mind%%29
