Epistemology of the Mind-Body Problem
One of the peculiarities of the mind-body problem is that any position is about as plausible as any other—or as implausible. That is, any position can be made to seem as plausible as any other—which is why every position has its adherents. Fashions may come and go, but the basic menu of positions doesn’t vary. It is not that everyone can see that some positions are simply hopeless; rather, some people are firmly convinced that a particular position can be defended to the exclusion of all others—that that position is actually true. Every position therefore has its staunch defenders: you find reductive materialists, token identity theorists, anomalous monists, property dualists, substance dualists, panpsychists, functionalists, computationalists, epiphenomenalists, eliminativists, and even idealists. Perhaps also there are other theories not yet formulated. And indeed something can be said in favor of every position—no position has nothing to be said for it. The trouble is that there are things to be said againstevery position too, though proponents tend to downplay such objections.
What does this tell us? Presumably some position is the true one, or is at least an approximation to the truth. There is a fact of the matter about the relationship between mind and body, a way things really are. The various positions are incompatible with each other, so they can’t all be true. So why can’t we select the correct theory? Why does every theory have its adherents? Many people (myself included) have veered from one position to another over the course of a lifetime, as the merits of one position assert themselves and the demerits of other positions appear inescapable. Why such heart-rending uncertainty, why such flip-flopping? One might have thought that since we have both a mind and a body the nature of the connection between them shouldn’t be so difficult to penetrate—after all, we have intimate knowledge of both. Maybe the deeds of distant stars are difficult to detect and explain, but it should be a straightforward matter to ascertain the relationship between the mind I know myself to have and the body that I also know so intimately. The mind-body problem should be an easy problem. Why isn’t it as easy as the “muscle-movement problem” or the “bladder-urine problem” or the “lung-breathing problem”? Why are we so blind?
There can really be only one answer to this question—that we lack the requisite methods to solve it. It is hardly plausible that we have the methods but are just too lazy or incompetent or prejudiced to employ them correctly. We are not like people with a measuring rod who simply can’t get it together to carry out the necessary measurements. The problem is that we don’t know how to solve the mind-body problem—we don’t know what method to adopt. We can already see that investigating the neural correlates of mental states will not resolve the problem, since the existence of such correlations is consistent with every available position. This method will not provide what we seek. Nor will the method of conceptual analysis produce the desired solution or else we would surely have found it long ago. The trouble is that the mind-body problem is an empirical (factual) problem that lacks an empirical method for solving it. Science can’t solve it, since the relevant science is neutral between the various options; but philosophical method is equally impotent—which is why every position has its adherents. Are people just being stubborn or biased? No, there is simply nothing in philosophy that forces one position over the others.
Our usual methods of discovery therefore fail us in the case of the mind-body problem. Our methods are one thing; the problem is another. It’s like trying to measure the height of a mountain with a floppy ruler. The methods are inadequate to the task. That is why the mind-body problem has the epistemology that it has: every position can be defended because none can be established. Maybe one day we will find a better method, and then the epistemology will shift; but it is hard to see what such a method might be, and nothing today looks like the beginnings of what is needed. In any case, as things stand we are methodologically bereft. This is why the characteristic pose of a theorist in this area is to give some (as he thinks) suggestive reasons why his position hasto be true and then challenge everyone else to refute the position in question. He doesn’t proceed by actually establishing the position he favors by marshalling facts and proofs. The epistemology of the mind-body problem precludes such a result. 
 It may be wondered whether other problems in philosophy share the epistemology I have described here. The short answer is that some do and some don’t, but I won’t go into this large question now. What I believe, however, is that the mind-body problem exemplifies this kind of epistemological predicament to a very marked degree.