Tallis, a Professor of geriatric medicine at the University of Manchester, and Fellow of the Academy of Medical Sciences, challenges the "orthodoxy", held by most neuroscientists and philosophers of the mind, that very soon scientists will be able to explain the mystery of human consciousness in terms of the activity of the brain. He stresses, however, that his argument is not about technical limitations; rather 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.
As you can imagine, I am very sceptical to all declarations by hard scientists of any kind when they pronounce the imminent end of all subjective uncertainties as soon as an "objective" science of brain and neuron and what-have-you functioning is finalized, and for this reason I read articles like the one by Professor Tallis with great interest.
Tallis' argument, in short, is that when we demonstrate specific and high correlations between modes of brain functioning and states of consciousness we have only managed to do as much. We have not managed to explain consciousness, locate it in the brain or "see" it in any scientifically meaningful way. He points out at the circularity involved when we unavoidably have to count on consciousness in order to observe consciousness. In other words, according to Tallis, any explanation of consciousness depends on the prior existence of consciousness, and therefore is circular and incomplete.
I find Tallis' argument very compelling and I would urge you to read the original and not count on my rendering of it here.
But I cannot stop myself from being surprised when I observe again and again just how much lacking in philosophical background and rigorousness all this debate about hard sciences and consciousness is. Tallis' argument is not very far from Heidegger's own; it's only that Heidegger is much more rigorous and systematic.
Heidegger would say that any question about consciousness is a secondary to the more primary question of being. Consciousness is a specific way of conceptualizing and "understanding" the world, and as such presupposes our being in the world, or as Heidegger writes it, being-in-the-world. It is because we are being-in-the-world that we can let entities, things, other beings, other human beings, reveal themselves to us. Consciousness, as such, as well as understanding, science, theories and so on, are only coming after, and any attempt to explain the human condition with them is incomplete, circular and fallacious.
You cannot explain the human condition Heidegger would say. You can only describe it.