There is the relationship between a reason and an action when the reason explains the action by giving the agent’s reason for doing what he did. The reason explains the action in this way (a reason that “rationalizes” the action) also causes the action. There is some confusion, then, about reasons for action. The idea of a “reason for action” seems to some most naturally to pick out considerations that count in favor of acting in a certain way, while to others it picks out psychological states that explain action. We believe that the relation has to be causal, in order to pick out, from among the many reasons that a person might have acted upon, those that the person did, in fact, act upon.
It is convenient to begin by considering dualism. The major position here is Cartesian dualism, named after Descartes, the central figure in post-medieval philosophical discussion of the mind-body problem. For a Cartesian dualist the mind and body are both substances; but while the body is an extended, and so a material, substance, the mind is an unextended, or spiritual, substance, subject to completely different principles of operation from the body. It was this doctrine that Gilbert Ryle caricatured as the myth of the ghost in the machine. It is in fact a serious and important theory.
In the Cartesian Dualism, the brain is part of the physical body but the mind or the spirit is not. The mind interacts with the physical body through the brain, more specifically, through the pineal gland in the middle of the two hemispheres of the brain. The body could be divided up by removing a leg or arm, but the mind or soul is indivisible. The mind is not only indivisible but also invisible and immortal. The body is the exact opposite being visible, mortal and divisible. The mind in Descartes explanation is a “thinking thing” (lat. res cogitans) and immaterial. This “thing” is capable of doubting, believing, hoping and thinking on its own.
The body is extended matter: the soul is unextended spirit. When, however, the extended is acted upon by the unextended, some definite point of interaction is required and it is to be found in the pineal gland. Yet the “soul is united to all parts of the body conjointly.” The whole body is the soul’s proper housing so long as the body remains intact. When a member of the body–an arm or a leg, for example–is cut off, there is no loss of part of the soul as a consequence because the soul is unitary and indivisible. It then occupies what is left of the body.
So without attempting to resolve all the problems, he simply stated that there is a dualism of mind and body, and their interaction is clearly real. The brain is the major locus for the mind or consciousness of the soul, yet mind or consciousness is distributed throughout the whole body. The point of interaction between the two is the pineal gland.
Monism is defined as “the doctrine that there is only one ultimate substance or principle, whether mind, matter, or some third thing that is the basis of both (or) the doctrine that reality is an organic whole without independent parts (Webster’s New World Dictionary).”
The concept of psychological dualism asserts that man is more than the sum of his genotype. Dualistic man has a mind that is separate from his body. This mind may be housed or contained within the body, but it is not contingent upon the physical body for its existence. The mind can act upon the body, and the body can act upon the mind, but they are separate entities that have been traditionally believed to separate at death at which point neither has any influence over the other. The most important aspect of this philosophy is its recognition of a non-biological component of the human person.
By the turn of the twentieth century, it had become clear that talk of “the mind” is too broad and that there may be issues to do with experience and sensation that are distinct from those that arise in connection with such mental states as believing, desiring, and the like (the so-called propositional attitudes). It was thought that, while functionalism, for example, might provide a plausible account of belief, it encountered real difficulties when it came to accounting for experience.
Functionalism is a material monist theory of mind: it asserts that everything is physical. It is highly significant both in that it develops behaviourism and that it paved the way for empirical work in neuro-physiology and cognitive science. It was created as Hilary Putnam interpreted conscious states in terms of the (then new) science of computational theory.
The function of the brain, states the theory, is ‘consciousness’. This approach is useful because by reducing the mind to a function it does away with the issue of how that function is performed. A function can be defined abstractly, without concerning itself with how that function is discharged in the same way that an equation can specify the relationship between X and Y without needing to specify how that equation might be solved. Thus, functionalism avoids the question of how the brain might achieve the feat of consciousness that dogs other materialist theories.
Functionalism is also both a response to and a development of behaviourism. Behaviourism argues that conscious states can be understood in terms of sensory input and behavioural output. This leads to a significant issue; namely that it ascribes conscious states to any input/output system (e.g. a water tank). Functionalism adds an intermediary step, arguing that sensory input is processed by a function before output.
Thus, two crucial differences to behaviourism are introduced: the function can lead to one or many outputs and some or all of the output can form the input to another internal function without the requirement for external expressive behaviour. With this simple device the diversity of the mind can theoretically be accounted for.
An everyday illustration of this process might be a car. It receives multiple inputs in the form of petrol, oil, water, etc and outputs motion, gases, heat, etc. During this transformation process (function) we can also see an example of feedback: some of the motion of the car is used to power the alternator to generate electricity, which in turn forms one of the inputs to the combustion process.
So now we have a brief understanding of the theory let us examine why this important theory came about. Firstly there is the need to respond to behaviourism and to overcome its shortcomings.
Functionalism can also be seen as developing along with other new concepts of the time. The new science of computers and computational mathematics supplied concepts that could be applied to the brain as a complex system. Functionalism was also applying empiricism to a new area, paralleling the method of the huge advancements made in science in the twentieth century.
Each mental state (or process) correlates with some neurological state (or process) Different mental states correlate with different neurological states (though one and the same mental state can have different neural correlates). The correlations are based on causal interactions between minds and brains. Mental occurrences can simply be taken as brain processes (Identity Theory). Mental states/processes are brain states/processes. Hence, we can identify sensations and other mental phenomena with (physical) brain processes.