Physiology has convinced most scientists and philosophers that there doesn’t seem to be any forces that are apart from the basic forces of nuclear, electromagnetic forces, gravitational forces. There doesn’t seem to be any effects anywhere that couldn’t be explained by those processes.
However, it’s not cut and dry: it’s still in principle possible that lurking in the interstices of our brain there are some special mental forces that no one has noticed yet. But there does seem to be any empirical or epistemological evidence for that, and there is an awful lot against it.
So how could the mind be physical?
If all physical effects have physical causes, then nothing that isn’t itself physical can have a physical effect. Look at the mind for instance. We have a choice here. Either you say it has physical effects, as it seems (my mental choices seem to be responsible for my arms moving around) in which case you have to say that the mind is physical. Or, you could bite the bullet and say that the mind cannot be physical, and therefore it doesn’t really have physical effects. And that’s the epiphenomenalist view. People who are persuaded that the mind can’t be physical, quite often, have to adopt this. They accept the conscious mind as kind of an epiphenomena: it floats above the brain, the brain does all the causing, and the mind is just a kind of pictorial accompaniment–it doesn’t do any real pushing itself. It observes what is going on but plays no real part in the causal proceedings.
There are still problems with the strictly physicalist view. The hardest thing to be a physicalist about is what Thomas Nagel got everyone talking about, the qualia point of view. People don’t have much trouble with the idea that bodies are just physical, and even some aspects of the mind it isn’t so hard to understand how it is physical. But when it comes to the conscious mind, that everything is physical is much harder to comprehend.
Biting the bullet for physicalism, at this point, then, must be difficult to comprehend in light of conscious experiences. However, working under the principle that this can all be explained in physical terms, then the conscious experiences must be physical effects. But are they? Can they in principle be located? Or is there something truly dualist about the conscious experience. What does epiphenomenalism have to offer? Nothing by way of explanation. Epiphenomenalism simply opens the door to more dualistic-like explanations. It doesn’t take a position on whether the conscious effect must be something completely different from physical substance. It seems to say that it simply isn’t something physical, which is to be a dualist about the situation.
Therefore, epiphenomenalism collapses into dualism completely, and there is no denying it. Epiphenomenalism is simply a new way of expressing the old problems that the dualists raise, and it should therefore be no surprise, and nothing to be moved by, as if it were some new sort of argument.