The architecture of the brain as a building consisting of superimposed neural loops helps to resolve that apparent gap between the Cartesian “external matter” (res extensa) and the “thinking matter” (res cogitans).
To overcome the conceptual obstacle of dualism, the concept of supervenience was introduced as a solution to reductionist explanations. Donald Davidson (1970) stated “mental characteristics are in some sense dependent, or supervenient, on physical characteristics”1. The term is a way to explain the concept of emergence of mental phenomena strictly associated with underlying physical properties. It has also been described as a form of non-reductive physicalism.
The Latin origin of supervene meaning ‘coming above’ describes well the process of the emergence of new properties in a stratified world. Although this perspective does not resolve the mechanisms underlying the emergence processes, it conceptually enables acceptance of the apparent discontinuity between one level and the b even as is generated by some ‘natural’ processes.
In order to overcome the epistemic gap, it is necessary to include the conscious observer in the process of regarding natural events as real, including mental events which themselves become the subject of personal observation. All observations are necessarily personal, including those of external events. This issue will be discussed in regard to the relation between subjective and objective experiences below.
My view is that the gap between mind and body is apparent at the very transition between the world and the brain, i.e. between the external world and the sensory and motor neurons of the nervous system.
The neuromechanical architecture of the primordial sensory-motor loop implies that there is a clear transition between the inner neural world, which operates according to the physics of electrochemistry in neural circuits, and the various physical events in the external world that interact with the neural organisms.
I suggest that the distinction of the two worlds of Descartes can be explained simply by the different kinds of physical processes at the interface between the external environment and the nervous system, in other words, two separate chapters of the same book of physics.
A clear transition between the res extensa and the res cogitans occurs at the primordial neuromechanical loops! This is the junction between environment and sensory neurons, where some physical event (res extensa) is translated in sensory neural activity (becoming res cogitans). A similarly dramatic transition occuer at the junction between of motor neurons (still res cogitans) and muscle where neural activity generates movements (becoming res extensa). These transitions i.e sensory transduction and neuromuscular transmission, are amongst the best studied phenomena in neuroscience and are well described in most textbooks. Fundamentally the two domains of the res cogitans and res extensa are unified by these two chapters of the physics.
These considerations should help to resolve the old debate based on historical misunderstandings of the apparent unbridgeable separation of the two Cartesian world domains.
- D Davidson (1970): Mental Events, in Essays on Actions and Events, Oxford University Press (2001) ↩︎