Some materialists argue that we can eliminate mental entities such as sensations because, like electrons, they are theoretical entities postulated as parts of scientific explanations, but, unlike electrons, they are unnecessary for such explanations. As Quine says, any explanatory role of mental entities can be played by "correlative physiological states and events instead." But sensations are not postulated theoretical entities. This is shown by proposing definitions of the related terms, 'observation term,' and 'theoretical term,' and then classifying the term 'sensation.' (...) The result is that although 'sensation' is a theoretical term, it is also a reporting term because it is used to refer to phenomena we are aware of. Consequently sensations are not postulated and cannot be eliminated merely because they are unnecessary for explanation. (shrink)