The mind-body problem stems from the problem of explaining the connection between minds, or mental processes, and bodily states or processes. For instance, we are all aware that our perception of a thing is brought about by stimuli from the external world that reaches several sensory organs and affecting the states in our brain resulting in feeling of a sensation such as pleasant or unpleasant. In the case of craving for food, it causes our body to move in order to fulfill our craving.
The debate though arises from the question on how does the brain does produces these seeming miracles in the form of conscious experiences? How does the desire instigate proper action? The philosophers of mind have been wondering about these mysteries since the time of Rene Descartes.
There are several opinions that try to resolve this mind-body debate which include the following:
Monism asserts that the only existing substance is the physical. And that the mind is part of the physical world. The flaw to this line of thinking though is it does not explain the fact that the mind contains properties that physical things do not such as the ability to reason.
Behaviorism theory eliminates the idea of an interior mental life. This theory ascribed feelings and thoughts to behavior. The problem though is how do behaviorist account for a headache? Headache could not be classified as a manifestation of behavior.
Identity theory is another theory proposes that mental states are not behavior but reflect the inner states of the brain. But if humans can feel pain so do animals like amphibians. And it is not possible for all of these creatures to be in the same brain state which makes the identity theory highly improbable.
Functionalism maintains that mental states are essentially characterized by their causal relations with other mental states and with sensory inputs and behavioral outputs. That is, it does away with the physical manifestation of a mental state by focusing on the non-mental functionality. For instance, functionalism does not concern itself with the physical make-up of the brain such as cells, tissues, etc. but its unique function in the body and its relation to other organs which gives its distinctive identity as the brain. Its limitation is that defining a substance according to its function somehow limits our idea of that particular thing.
Interactionism Theory or Interactionist dualism, or simply interactionism, is the specific form of dualism first proposed by Descartes in his work the Meditations. The major adherents of Interactionism in the 20th century are Karl Popper and John Carew Eccles. This theory supposes that the mental states, like beliefs and desires, causally relate with physical states.
To state it simply a person experiences two kinds of events, physical and mental, either of which can affect the other; for instance, being pricked by a pin causes pain and pain manifests physically by screaming.
More usually, though, it is a philosophical theory based on interactions of the existence of two substances, body and mind (or soul), where physical events occur in the one at the same time mental events take place in the other. Both series of events can interact and affect the other such as in the example shown above. This is the theory proposed by Rene Descartes (1596-1650) but the idea was present even before particularly during Plato's time (c. 427-c.347 BC).
