Here is a graph where a person can map their own beliefs on questions of mind-brain, and map the positioning of other thinkers across the past-present-future continuum.
The movement from left to right are possibilities of belief from an unquestioning supernaturalism to an empty materialism. Supernaturalism hangs on the ancient idea of soul but it is possible to carry that concept into a soft naturalism. The difference between the ancient conceptions along with, today, the thinking of naive modern fundamentalists, against the rest of our population, is that the supernationalism is so unquestioned that it has what most consider as a comical character. God is a comedian or super hero or super villain, quite literally.
As soon as a methodological naturalism is adopted – and it begins with the ancients – it changes the game completely. Naturalism is basically the argument that supernatural entities – what we determine is above/outside the ordinary patterns (of science or common sense observation) – has no bearing on judgement. However, judgement can consistently work as compatibly between opposing principles or basic beliefs. Apparent contradictions might be resolved in a different rearrangement than what came before. Methodological naturalism is often the rearrangement – rearrange natural features into a theory without recourse to supernatural items.
Therefore, it is common to have modern neo-evangelical Christian believers who articulate a soft naturalism via sufficient methodological naturalism where the supernatural supervenes, as a belief, which has no part of a naturalistic explanation. The structure of the belief frame can be seen in Stephen Jay Gould’s Non-overlapping magisteria (NOMA).
However, there is a further step that both Christian and Post-Christian believers have taken, and into a harder naturalism. The step is taken when a serious concept of ‘soul’ is abandoned for a focus on consciousness. Soul is now the empty metaphor, although useable as a literary device to describe ‘the spirit’, what is much better conceptualised as person or consciousness. Here is the complete abandonment of the Cartesian dualism, which, to the modern enquiring mind, appears as comical as the ancient soul.
However, it is still possible to retain a basic duality of mind and body where the mind is what we describe as what emerges/emerged in brain activity. At this stage of the spectrum there is greater latitude in explanation, for the very reason that ‘consciousness’ is a relatively new field and there is still considerable uncertainty or contention. Specifically, there are highly technical internalist-externalist debates which extend over into the fields of ontology, meta-ethics and epistemology. Currently, the idea of the ‘embodied self’ extents across the divide, but the more one pushes into a radical or naïve empiricism, which reject more and more of the theoretical components for the trust in the observational statements, the more the concept of ‘self’ is abandoned. When it is completely abandoned we are left with ‘the empty material body’. There is no internal reasoning but only external judgement.
The arrival in materialism also rejects any notion of duality or any layering beyond material existence. Materialism here might be better described as hard materialism whereas hard empiricism can be seen as a softer materialism with the possibilities of the observing self. The reduction move – cutting back the layers of internal reasoning – in the methodological naturalism has reached an absolute in the radical materialism.