Tuesday, September 25, 2012

Interactionist dualism versus epiphenomenalism

To: Kathleen C.
From: Geoffrey Klempner
Subject: Interactionist dualism versus epiphenomenalism
Date: 27th May 2008 11:43

Dear Kay,

Thank you for your email of 13 May, with your third essay for the Philosophy of Mind program, in response to the question, 'Contrast the main features of interactionist and epiphenomenalist versions of mind-body dualism.'

With my University of London external students safely through their exams, I allowed myself to be very lazy last week. I came back to my office this morning after the Bank Holiday with 126 emails to sort through!

The question refers to an 'epiphenomenalist version of dualism'. Confusingly, recent debate in the philosophy of mind has focused on arguments for and against epiphenomenalism within a broadly materialist/ physicalist view of the mind.

It seems obvious, as you argue, that if human beings are the products of evolution then the capacity for consciousness, viewed from a dualist standpoint as the capacity to emit or produce non-physical mental events would seem the purest case of evolutionary baroque, sheer accident so far as our physical capacities are concerned.

However the question is not quite so simple when one factors in debate over epiphenomenalism within a materialist view. It all depends on how one views the 'direction of explanation' in accounting for the way in which physical events in the brain cause, and are caused by external events in the world (in the former case bodily movements, in the latter case perceptions).

On a 'non-reductive' materialism, there is a genuine role for explanation in terms of beliefs, desires and intentions -- the terms of 'folk psychology' as philosophers call it -- which is in some sense prior to explanation on the purely neurological level. The question is, are the explanations we give in folk psychology real, or merely illusory? When I tell you that I converted the file you sent me for printing, in order to have a copy to read when I responded to your essay, is that the literal truth about the processes of cause and effect, or is the real story one about neurons firing? In the latter case, what we term 'belief' or 'desire' -- or 'consciousness', viewed from a materialist perspective -- are just epiphenomena relative to what is really going on underneath the bonnet, in the brain. As we give our explanations in folk psychology, we are under the illusion that we are offering genuine explanations, when in fact we are not.

The question of the role of consciousness in evolution now acquires a new twist. Human beings do need the capacity for consciousness in order to accomplish tasks which could not be accomplished without it. But even accepting this point still doesn't settle the question over the reducibility or non-reducibility of folk psychology. It all depends on how one explains 'consciousness' from a materialist point of view.

On the question of Cartesian mind-body interaction and speculation about quantum effects in the brain, the point here is that the conservation of energy is preserved provided that the overall rate of change (e.g. radioactive decay) is what would be predicted by our knowledge of physical laws. There was a series of experiments conducted at my old college, Birkbeck, a few years ago by an eminent physicist who got subjects to attempt to 'predict' when a click would sound on a Geiger counter. The idea being that, even if the overall number of clicks per hour or per minute is preserved, there might yet be a measurable correlation between predictions and clicks, implying some kind of 'interaction' between the subject's mind and the radioactive sample. (I heard this second-hand, but I understand that the experiments were inconclusive.)

Radioactivity is not the only example of a quantum phenomenon. Another is the humble neon light, which is actually the combined effect of billions of individual random flashes. Perhaps by thinking hard enough, you could cause your name to be spelled out on the neon light in your kitchen. Even if you only succeeded in causing a momentary flicker that would be an astounding result. (Of course, you could never know for sure -- but suppose you were able to repeat the experiment on demand.)

It is impossible to rule out, at the present state of scientific knowledge, that the changes which occur in the neurons of the brain are governed by a similar 'probabilistic' effect which is indeterminate at the quantum level, allowing for the possibility that the brain could function as a 'relay' mechanism between the physical body and a Cartesian soul substance. We don't even need to posit soul substance. Just call the mind a non-physical force and leave the question of its identity open.

I'm not sure you've grasped the point about criteria of identity. In the unit, there were two arguments given, one against the materialist and one against the dualist.

The point against the materialist who accepts the story about 'inner somethings' at face value but insists that they are 'identical' with events in the brain, is that there is no criterion for this identity statement. One-to-one correlation would be indistinguishable from identity. Nothing is gained by using the term 'identical'.

The point against the Cartesian dualist is that there is no criterion for the 'identity' of soul substance across time, or indeed for the number of soul substances associated with a given body. There could be a thousand 'souls of GK' thinking the thoughts that lead to these words being typed on the screen and it would not make any difference, so talk of 'number' is empty. Or, 'the' soul of GK could die every second and be replaced by a qualitatively indistinguishable soul, and 'I' would never know the difference.

All the best,