Is the mind-body interface microscopic?

This paper puts forward the hypothesis that consciousness might be linked to matter in a way which is more sophisticated than the traditional macroscopic Cartesian hypothesis suggests. Advances in the biophysics of the nervous system, not only on the level of its macroscopic functioning but also on the level of individual ion channels, have made the question of 'how finely' consciousness is tied to matter and its dynamics more important. Quantum mechanics limits the attainable resolution and puts into doubt the idea of an infinitely fine-woven attachment. A recent approach to physics rekindles such a rationalist hope. 'Endophysics' focuses on the global implications of microscopic computer simulations of chemical and biophysical processes. A complete 'artificial universe' can be set up in the computer. It produces non-classical and nonlocal effects inside--on the 'interface' that exists between an internal observer ('fluid neuron') and the rest of the world. This interface is finer than any brain property to which the status of the mind-body interface has been attributed hitherto. A new class of experiments becomes possible in the artificial world and, by analogy, in the real world. Magnetic resonance imaging experiments, routinely performed under open-loop conditions, can be repeated under psychophysical (closed-loop) conditions--in search for microscopically induced changes in the perceived and measured structure of the world.