The main hindrance for dualism is to explain how something non-physical (mind, soul) is associated with something physical (body). According to dualism, the association between the person (mind, soul) and the body is so intimate that many people falsely believe they are indistinguishable from their bodies. Descartes says its because they have never had the experience of being without their body.
The opposing belief of dualism is physicalism, which states that there is no association of the mind and body because the person is physical throughout. So how should this association be understood?
A common response among dualists is that the association is one of direct interaction, a two-way interaction in which the soul affects the body and vice versa. Physicalists charge that it is relatively difficult to pin down a concrete conception of such an interaction and put it into the dualist frame of mind.
For example, being hungry, I get in my car and go get something to eat and proceed to eat it. There are many physical changes that took place that can be explained in terms of physical science. Not so, says the interaction principle, which would state that I, my soul, brought about these changes because my body was hungry; the changes are from me even though are not in me but in my hungry body.
The main problem isn t about what the causal agent is that brings about physical changes. Rather, how it causes the changes is the major concern. Dualism has yet to successfully explain that and will continue to appear as a conceptual blind alley those who are skeptical of it.
After dualism was refuted, there had risen a primary concern among the intellectuals: How are we to successfully talk about mental causes without referring to dualism s Cartesian soul? There emerged materialism.
In short, materialism contends that the mental is not separate from the physical, as opposed to dualism. In fact, all mental states, operations, etc. are (in principle) identical to that of behavioral states, operations, etc.
A portion of materialists known as behaviorists believe that all talk about mental causes can be eliminated from the languages of psychology, putting talk of environmental stimuli and behavioral responses in its place. Other materialists, know as central-state identity theorists (or reductive materialists), believe that such mental states are actually neurophysiological events in the brain. Out of the behaviorists approach emerged methodological behaviorism and logical behaviorism. Methodological behaviorism was eventually refuted for reasons I shall not go into. It was around the 1960 s that logical behaviorism came into the realm of philisophical-psychological thought.
According to Fodor, [l]ogical behaviorism is a semantic theory about what mental terms mean. In other words, all talk about (sentences describing) mental phenomena can be translated into talk about dispositions to behave in certain ways.
For example, to say John is thirsty (thirst being a mental state), is the same as saying If there was water available, then John would drink it. In this example, the mental state – or stimulus – equals by definition in the if-then statement (also called a behavioral hypothetical) the response, or behavioral disposition (John drinking the water that is available). Since stimuli and responses are physical events (according to materialism), logical behaviorism avoids dualism s unanswered theory of mind-body interaction. This is a promising move.
Moreover, logical behaviorists are not saying that John doesn t have beliefs. Indeed they contend that he does, but those beliefs are merely a shorthand way of referring to behavior. They also want to make it quite clear that each mental phenomenon isn t necessarily translated into a single behavioral hypothetical. Rather, the logical behaviorist often suggests that there is an open-ended set (quite possibly an infinite set) of behavioral hypotheticals that can be used to explain the stimulus-response interaction (mental term-behavioral disposition interaction).
In knowing this, the previous example, John is thirsty, could also be satisfied with the hypothetical, If there were Gatorade within John s grasp and he was thirsty, then he would drink it. In any event, the logical behaviorist does not suggest he can conceive of every behavioral hypothetical given a mental state, but that the mental states can be translated into a behavioral hypothetical.
This explanation of a mental term can be modeled after the same way philosophers referred to physical, nonbehavioral dispositions. For example, take the relationship between friction and heat. The physical disposition, friction creates heat, could be put into a hypothetical If two physical objects are rubbing against one another (friction), then they would create heat. On this note, the logical behaviorist s analysis of mental causation is similar to the analysis of physical causation. The causal statement Heat was created by the two physical objects rubbing against one another is taken to mean something like If two physical objects are rubbing against one another (friction), then they would create heat, and there are two objects rubbing against one another.
So, by defining mental terms as behavioral dispositions, the logical behaviorist has then put mental terms on the same level as nonbehavioral, physical dispositions. This is a strong point because the analysis of physical dispositions is on a relatively solid foundation with very few valid objections brought against it.
As with every other theory, logical behaviorism has some flaws. For one, equating mental terms on the same level as nonbehavioral dispositions only works with a selection, and not all, of behavioral dispositions. Indeed, logical behaviorism believes that the manifestation of a disposition solely originates from mental causation. However, physical science (the same physical science logical behaviorists used to strengthen their main claim of behavioral dispositions) has explored and found that there are additional forms of causation; one being where one event causes another event.
In the previous example about John being thirsty, there are events that caused other events to his being thirsty and having the disposition of drinking water (or whatever) if available. In fact, it is presumably less difficult to explain event-event causations as opposed to mental term dispositions because the latter requires the former, and the former does not require the latter. Logical behaviorists also fail to give any correct analyses of statements containing mental terms.