Ray Tallis | Waking Times
Most neuroscientists, philosophers of the mind and science journalists feel the time is near when we will be able to explain the mystery of human consciousness in terms of the activity of the brain. There is, however, a vocal minority of neurosceptics who contest this orthodoxy. Among them are those who focus on claims neuroscience makes about the preciseness of correlations between indirectly observed neural activity and different mental functions, states or experiences.
This was well captured in a 2009 article in Perspectives on Psychological Science by Harold Pashler from the University of California, San Diego, and colleagues, that argued: “…these correlations are higher than should be expected given the (evidently limited) reliability of both fMRI and personality measures. The high correlations are all the more puzzling because method sections rarely contain much detail about how the correlations were obtained.”
Believers will counter that this is irrelevant: as our means of capturing and analysing neural activity become more powerful, so we will be able to make more precise correlations between the quantity, pattern and location of neural activity and aspects of consciousness.
This may well happen, but my argument is not about technical, probably temporary, limitations. It is about the deep philosophical confusion embedded in the assumption that if you can correlate neural activity with consciousness, then you have demonstrated they are one and the same thing, and that a physical science such as neurophysiology is able to show what consciousness truly is.
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.