There is now a more satisfactory range of ideas available [in the field of consciousness studies]... They involve mostly quantum objects called Bose-Einstein condensates (see Marshall, or Zohar), which may be capable of forming ephemeral but extended structures in the brain (Pessa). Marshall's original idea (based on the work of Frölich) was that the condensates which comprise the physical basis of mind, form from activity of vibrating molecules (dipoles) in nerve cell membranes. One of us (Clarke) has found theoretical evidence that the distribution of energy levels for such arrays of molecules prevents this happening in the way that Marshall first thought. However, the occurrence of similar condensates centring around the microtubules that are an important part of the structure of every cell, including nerve cells, remains a theoretical possibility (del Giudice et al.). Hameroff has pointed out that single-cell organisms such as 'paramecium' can perform quite complicated actions normally thought to need a brain. He suggests that their 'brain' is in their microtubules. Shape changes in the constituent proteins (tubulin) could subserve computational functions and would involve quantum phenomena of the sort envisaged by del Giudice et al. This raises the intriguing possibility that the most basic cognitive unit is provided, not by the nerve cell synapse as is usually supposed, but by the microtubular structure within cells. The underlying intuition is that the structures formed by Bose-Einstein condensates are the building blocks of mental life; in relation to perception they are models of the world, transforming a nice view, say, into a mental structure which represents some of the inherent qualities of that view.
We thought that, if there is anything to ideas of this sort, the quantum nature of awareness should be detectable experimentally. Holism and non-locality are features of the quantum world with no precise classical equivalents. The former implies that interacting systems have to be considered as wholes -- you cannot deal with one part in isolation from the rest. Non-locality means, among other things, that spatial separation between its parts does not alter the requirement to deal with an interacting system holistically. If we could detect these in relation to awareness, we would show that consciousness cannot be understood solely in terms of classical concepts.