Neuroscience and the Mind

Neuroscience struggles with the notion of consciousness.  It is considered the final frontier for brain scientists.  Much energy has been expended in the laboratory in an attempt to unravel the neural correlates of consciousness (NCC).  There can be little doubt that the neural connectivity within the brain is nothing short of astounding.  The brain is an organ that acts as an integrated CPU (central processing unit), stores memory, can repair itself, mediates the senses, controls pain experience and manages many body processes.  Is it the source of the phenomenon identified as consciousness?

In this chapter I will endeavour to summarise what neuroscience can tell us about the mind and consciousness.  I will visit Hameroff and Penrose’s exploration of microtubules within the brain as the seat of consciousness. 

The Axiomatic Approach

In this approach neuroscientists draw on the theory of “Integrated Information Theory (ITT)” and claim to have tackled the “hard problem of consciousness” by asserting that consciousness is really information processing.  Therefore all creatures and machines which process information are said to be conscious.  An axiom, in this context, is said to be a guided hypothesis:  

“Consciousness exists: My experience just is. Indeed, that my experience here and now exists—it is real or actual—is the only fact I am immediately and absolutely sure of, as Descartes realized four centuries ago. Moreover, my experience exists from its own intrinsic perspective, independent of external observers. (Tononi and Koch 2015, 5).”

Bayne, Tim.  On the Axiomatic Foundations of the Integrated Information Theory of Consciousness.  Neuroscience of Consciousness, 2018, 4(1): niy007

There are a number of axioms which underpin this view:

1. The axiom of intrinsic existence which suggests that consciousness exists as a genuine phenomenon of the world and is not a construct.

2. The axiom of composition proposes that conscious experience is composed of elements, for instance objects, colours and timeframes.  Critics of this axiom point out that not all conscious experience is structured.

3. The axiom of information captures the notion that the contents of consciousness are holistic.  It is not singular but contains bundled experience which is itself information.

4. The axiom of integration, similar to the axiom of information, is that consciousness is unitary and composed of sets of phenomena which are irreducible.

5. The axiom of exclusion is that the contents of consciousness are definite and would seem to rule out the possibility that the contents may, at times, be vague and difficult to grasp.

 The axiomic approach sets up a number of propositions for defining consciousness.  However, Baynes suggests (the axiomic approach) may not be well suited to the study of this phenomenon, which may be a far more fluid and variable than scientific method can readily study.  The neural correlates of experience can certainly tell us something about the workings of the brain.  However, does this equate to consciousness? 

Psychedelics and Consciousness

Bayne (2018) discusses the prospect that there are two distinct notions of consciousness:  “Contents of Consciousness” and “States of Consciousness”. The contents of consciousness can be thought of as dimensions such as auditory and visual experience, taste, smell and cognitive content.  States of consciousness are more complex.  Some suggest heightened awareness at one end of the spectrum through diminishing levels to unconsciousness.  The neural correlates of these states can be observed through brain imaging.  States of consciousness may be overlaid with emotions.  These would seem to have both content and impact on state.

 Bayne and Watson explore the impact of psilocybin and LSD on states of consciousness.  In particular they draw on studies that report on the subjective experience of participants in changes in sensory experience, cognitive capacities and perception of time, space and self.  Participants report enhanced sensory experience, increased bandwidth, that is, access to greater sensory content.  In terms of cognitive capacities there appears to be a decrease in capability associated with these psychedelic states; in particular capability to complete tasks involving mental control.  Many reported that time had slowed down or stopped and that the sense of separateness of self dissipates (ego dissolution). 

This neuroscientific view of consciousness is useful for the study of our everyday mental functioning.  If, as Harari predicts, more sophisticated pharmacological approaches assist to diminish what are perceived to be negative states of consciousness, then neuroscience has a role to play. 

Microtubules as the Seat of Consciousness

This quote from renowned physicist Roger Penrose and professor of anaesthesiology and psychology, Stuart Hameroff is informative of the neuroscientific view:  

“The nature of consciousness, its occurrence in the brain and its ultimate place in the universe are unknown.  We proposed in the mid-1990’s that consciousness depends on biologically ‘orchestrated’ quantum computations in collections of microtubules within brain neurons, that these quantum computations correlate with and regulate neuronal activity……………..”

Penrose, Roger and Hameroff, Stuart.  Consciousness in the Universe:  Neuroscience, Quantum Space-Time Geometry and Orch OR Theory  in Quantum Physics of Consciousness.  Kak S. Penrose R. and Hameroff, S (Eds).  Cosmology Science Publishers, 2017.

They postulate three possibilities for the origins of consciousness:

1.  Firstly that consciousness is a naturally occurring phenomenon that evolved biologically through the brain and nervous system.

2. Consciousness is a property of the universe and has always been present.  In one sense all objects are conscious and some argue that only consciousness exists in the universe and the material world has no existence without it (see quote from B. Alan Wallace on Page 4).

3. The precursors of consciousness have always been present in the universe.  Biology evolved a mechanism by which precursors could be converted into actual consciousness.  This is the basis of the Penrose-Hameroff ‘orchestrated objective reduction’ (‘Orch OR’),  p230.

 Microtubules within brain neurons are seen as functioning as a ‘bio-molecular computer’ giving rise to consciousness.  This hypothesis, however, is difficult to test from the first person perspective.

Concluding Comments on Neuroscience and Consciousness

Not surprisingly neuroscience tells us quite a lot about the neural correlates of consciousness.  But not a great deal about consciousness itself.  Brain activity can be mapped in response to certain stimuli.  Neuroscientists can identify what happens to aspects of consciousness in response to brain injury.  But this tells us little about the luminous quality of awareness that occurs when a new and creative idea finds its way into our thinking.