07 June 2013

Dennett and reports on consciousness...

I've been reading some Daniel Dennett lately (both Consciousness Explained and his new Intuition Pumps) and reflecting on many of his concepts.  Dennett argues for what he calls hetero-phenomenology as a method of scientifically researching consciousness, and this is basically taking reports from subjects in as neutral a way as possible (i.e. minimizing assumptions), and then trying to evaluate and explain these reports (i.e. are they right, what causes them, etc.).  In at least some descriptions, he seems to see the goal as simply a binary true/false evaluation - presumably on whether the perception matches what's really evident (as judged by objective observers).

Rather than a simple binary evaluation of right/wrong, I propose there are multiple angles that can and should be examined.
1. If the report includes descriptions of the world outside the subject, how do these compare to reports of 3rd parties? Or to other measures of reality?
2. If the report includes descriptions of internal sensations, how do these compare to what we know about the physical basis for the senses?
3. If the report includes an explanation or reason for the subject's experience, how does that compare to various existing theories and studies of behavior?

So in the case of the blind spot, I think most people will not report any blind spot, unless they follow a specific procedure, by staring at one point while moving another point that is off to the side closer or farther away until it can't be seen.  Physically we know there are no rods and cones at the back of the eye where the optic nerve exits.  So on criteria 1, there is actually a good match with reality because there appears to bear "filling in" of the spot, likely achieved because the eyes are usually shifting around, not starring at one point, and somehow a full visual field is produced (criteria 2).

Many visual illusions indicate that the perception includes features that are not really in the picture.  This seems to indicate that there is construction or filling in of apparent patterns.  In general I suspect this is a useful feature in dealing with the world, in particular for cases where what we are looking at is partially obscured.  

Now consider a case where the subject unknowingly has been given a drug that commonly causes hallucinations.  The subject reports that the furniture appears to be melting.  Here there is an incorrect match with reality.  If the subject reports that he may be "losing his mind", hopefully the observer will let them know that in fact the experience is due to a drug and will end soon.  The subject did not really know the reason for the experience.
While the subject's report about the outside world is clearly wrong, I don't think we can say that the subject's internal experience is wrong or untrue.  In this case we know the drug has the neurochemical properties which has one effect of altering the subject's experience.

In other cases of anomalous internal experiences, like a near death experience or an out-of-body experience, we can say that other observers in the immediate area could not detect any outside (i.e. real world) trace of it, but not that the report is wrong per se.  I think it's worth trying to both explain how such experiences can occur, and whether such experiences are a result of and/or can result in physical changes (such as neuronal rewiring).

No comments: