As with many philosophical theories, Eliminative Materialism is difficult to define, apart from the way it contrasts with other theories. Eliminativism is basically a specialized form of the identity theory; it’s main point of difference being that it denies the existence of intentional states. This means that an eliminativist believes that there are no beliefs or desires and (most likely) desires to tell us this. At first glance this theory seems totally useless, denying the existence of beliefs and desires? Maybe so, but before with rubbish it, we should look at why they want to take this radical step. When Eliminative Materialists where trying to come up with at theory of mind, they thought back to other times when people tried to explain phenomena and how some of those attempts failed miserably. For example at one stage people thought that heat, was some kind of a fluid, called caloric fluid, and when something got hotter it simply had obtained some more of this fluid. At the time this sounded like a good idea, so scientists set out to prove it, but discovered that heat was not a fluid but just molecular motion inside the substance its self. What if beliefs and desires are the same? What if our beliefs and desires are just made up entities, like caloric fluid, to help fit our theory? If they are just made up entities essential to intentional systems theory and folk psychology, maybe we shouldn’t use them in our theory at all. Just because they are important parts of the main theories doesn’t mean you have to try to include it in your theory. In the light of this the eliminativist says we shouldn’t try to explain beliefs and desires, because they could be wrong. Instead lets focus on things like pain and directly observable states, and then find whatever it is that causes those behaviors we explain in terms of beliefs, desires, and rationality. An eliminativist wouldn't have to say you can’t talk of belief and desires, just as an astrophysicist wouldn’t have to stop you from talking about the sun rising in the morning. They would say, you can talk about them all you like, make predictions (eg the sun will rise tomorrow), and be correct. The only difference is that when you talk about the sun rising, you are talking about something that doesn’t really happen. The sun doesn’t ‘rise’ the earth turns so that it becomes visible. An Eliminativist might say that you can talk of beliefs and desires but they aren’t really what’s happening. Inside your brain there is no state exemplifying a belief/desire. Ie they can’t say, ”oh look this part of his brain is active he must have a belief”, or “look he must desire a beer”. These types of brain states in eliminative materialism don’t exist. They say we must instead look for what it is that does the job that we explain in these terms. So a rephrase version of my sentence at the beginning of this essay might go like this. “Eliminative Materialists believe that there are no brain states that exemplify Beliefs or Desires, and they desire to tell us this.”
This is not the end of the story though, while eliminativists say that beliefs and desires are made up entities designed for folk psychology, others would classify them as a directly inferred concept and therefore an essential part of a theory of mind. The difference is whether beliefs are like heat or caloric fluid. If beliefs are like heat, then they will always exist, even if our concept of them changes somewhat. Although heat was once thought to be caloric fluid, the basic underlying idea that there was some thing that made things hot or cold (called heat) still remains; despite the fact that it turned out to be no more that internal molecular motion. However if heat is like caloric
