The Wikipedia article on eliminative materialism has undergone a radical transformation since the end of January. It is now a clear and comprehensive introduction to one of the most important philosophical approaches to modern cognitive science.
Philosophers, unfortunately, have an image problem. Ask the average person in the street about what philosophers do and you’re likely to be informed that they try and work out whether God, reality or each other exist.
In reality, a significant number are involved in the cognitive sciences and are doing some much needed structural work on the foundations.
Philosophy of mind focuses on understanding and testing the foundations of psychology and cognitive science, and is now an essential partner in the bid to explain human thought.
The majority of theories about the mind make assumptions about the sort of mental states we have. Many of these assumptions are taken from everyday language and culture, and are usually described by ‘common sense’.
For example, the everyday concept of ‘belief’ features regularly in scientific explanations of the mind, despite the fact that this concept is often applied so widely in natural language as to be seemingly contradictory in places.
A school of thought called ‘eliminative materialism’ argues that these ‘common-sense’ concepts are like the ancient four humours theory of medicine – which said that the body and mind are controlled by levels of ‘blood’, ‘black bile’, ‘yellow bile’ and ‘phlegm’.
Although this theory was assumed to be true at the time, modern science hasn’t given us an improved explanation of the ‘four humours’, it has rejected the idea as completely ridiculous.
Eliminative materialism argues that everyday concepts like ‘belief’ and ‘desire’ will suffer the same fate because of their inconsistencies, and that theories that use these concepts are ultimately flawed.
Supporters also point to the lack of clear evidence that these everyday concepts are linked to any consistent pattern of brain activity. This might suggest that these concepts are also not supported by other, similarly intentioned, approaches.
If eliminative materialism is accurate, many past theories will have to be re-thought, and how we test, create and think about the mind and brain will change radically.
It is not clear, however, whether it is accurate, and the recently updated Wikipedia page gives an excellent and evolving account of the arguments.
Link to Wikipedia article on eliminative materialism.
Mind Hacks 
At first glance there appears to be a confusion between observation and explanation. The four humours is an explanation of how the body works, while illness is an observation. Just because something hasn’t been explained does not mean it does not exist. Besides, surely the neurological basis for beliefs, desires and even love are starting to be discovered. The more we discover, the more our definitions of these concepts will change, but I cannot see this movement having any noteworthy effect on psychology.