Ethics

"You Won't Find Consciousness in the Brain"

By Adam Kolber

Ray Tallis, in New Scientist, claims that "You Won't Find Consciousness in the Brain".  Here's a sample:

Many neurosceptics have argued that neural activity is nothing like experience, and that the least one might expect if A and B are the same is that they be indistinguishable from each other. Countering that objection by claiming that, say, activity in the occipital cortex and the sensation of light are two aspects of the same thing does not hold up because the existence of "aspects" depends on the prior existence of consciousness and cannot be used to explain the relationship between neural activity and consciousness.

This disposes of the famous claim by John Searle, Slusser Professor of Philosophy at the University of California, Berkeley: that neural activity and conscious experience stand in the same relationship as molecules of H₂O to water, with its properties of wetness, coldness, shininess and so on. The analogy fails as the level at which water can be seen as molecules, on the one hand, and as wet, shiny, cold stuff on the other, are intended to correspond to different "levels" at which we are conscious of it. But the existence of levels of experience or of description presupposes consciousness. Water does not intrinsically have these levels.

We cannot therefore conclude that when we see what seem to be neural correlates of consciousness that we are seeing consciousness itself. While neural activity of a certain kind is a necessary condition for every manifestation of consciousness, from the lightest sensation to the most exquisitely constructed sense of self, it is neither a sufficient condition of it, nor, still less, is it identical with it. If it were identical, then we would be left with the insuperable problem of explaining how intracranial nerve impulses, which are material events, could "reach out" to extracranial objects in order to be "of" or "about" them. Straightforward physical causation explains how light from an object brings about events in the occipital cortex. No such explanation is available as to how those neural events are "about" the physical object. Biophysical science explains how the light gets in but not how the gaze looks out.

Full post as published by Neuroethics and Law on January 12, 2010 (boomark / email).