There seems to be a consensus in modern neuroscience and philosophy that understanding the processes underlying states of consciousness is the ultimate frontier for humankind.
In medical sciences, the “conscious state” refers to a state of alertness and awareness underlying responsiveness to external stimuli. Following this definition, lack of consciousness occurs in deep sleep, under general anaesthesia, in states of coma, and in some pathological states such as epilepsy. Identifying the neural correlates of consciousness therefore is important scientifically and clinically to improve the detection of conscious awareness. In turn this will help design new therapies in patients who remain unresponsive after brain damage1.
It is generally agreed that conscious beings are aware of themselves, their surroundings, and their own perception, memories, thoughts and emotions. As such, consciousness is thought to require the dual capacity for wakefulness (arousal) and awareness of oneself and one’s environment2.
Having conscious experiences with specific content is often referred to as phenomenal consciousness and can be best regarded as a physiological state of an organism, associated with being aware of some aspect of the world, of oneself, or be aware of being aware3.
The specific contents of conscious experience, with their unique subjective experiences are much harder to directly correlate to specific neural activity. Qualia is a term used in philosophy to describe what is like to feel something for a subject, to experience the uniqueness of a particular experience for example of ‘red colour’ (or what is like to be me, or, as famously asked by Thomas Nagel, what is it like to be a bat?).
I will present arguments to equate this apparently insurmountable obstacle with other situations in which similar issues that have been addressed successfully with little epistemological drama. The conceptual frame includes naturalising subjective experience as an emergent property of the highest levels of superimposed loops in the brain.
A more abstract use of the word consciousness refers to the very nature of having subjective experiences. Over centuries, many thinkers were compelled to search for a philosophically clear definition of consciousness. Consciousness in this conception has been often assumed by idealist philosophers to be a kind of essence, with an ultimate nature as an entity totally separate from its existence in the physical world. As discussed above, this view is known as substance or Cartesian dualism. A version of dualism called property dualism denies materialism, claiming that phenomenal properties are non-physical properties: there is just one sort of substance or entity that has both physical and phenomenal properties. For example, the “redness” of the experience of seeing the tulip may be a property of the brain state involved, but it is distinct from any physical property of this state.
Another view of consciousness known as panpsychism claims that phenomenal properties, or simpler but related “proto-phenomenal” properties, are present in all fundamental physical entities. A panpsychist might claim that an electron, as a fundamental particle, has either a property like the “redness” of the tulip experience or a special precursor of this property.
Contrasting with all of the above views, materialism also called physicalism, claims that consciousness is a wholly physical phenomenon. Conscious experiences are states of the physical world – typically brain states – and the properties that make up the phenomenal character of our experiences, known as phenomenal properties, are physical properties of these states. For example, a materialist might claim that the experience of seeing a red tulip is a particular brain state and that the “redness” of the experience is a feature of that state.
As I mentioned above, scientific strategies have been applied successfully to investigations of most natural phenomena. This approach consists of establishing the physical factors that affect a particular phenomenon and the conditions that are sufficient for the phenomenon to occur. Extending this strategy to correlate the content of phenomenal experiences with specific neural states involves establishing experimentally the physical factors capable of affecting subjective experiences. The effectiveness of this strategy can be demonstrated if mental states can be shown to be based on specific states of the nervous system and that they can be manipulated as all other physical phenomena.
Evolution of states of consciousness
While states of conscious experience are clearly absent at the spinal cord level, Jaak Panksepp has suggested how consciousness evolved from lower animals and how it relates to subcortical midline structures and affective states4.
Antonio Damasio like Panksepp, sees the lower brainstem centres as essential to a proto-self and sees “subcortical and cortical somatic maps within the central nervous system” as essential components of a conscious self. The circuits involving the thalamus and the thalamocortical loops and the cerebral cortex are essential for a sense of self to develop in full5. From a somewhat comparable point of view, Anil Seth argues that the gradation from sub-conscious to conscious states occurs in sharpish transitions, each emerging from lower levels6.
The process of developing a sense of self can also be described as the search for an ‘identity’, a unity. This process is highly linked to early experiences including the place where one has grown up, one’s kinship relations, schooling period, and one’s broader social environment with its customs, myths, religions, and political systems.
- O Gosseries et al (2014): Measuring consciousness in severely damaged brains. Annual Review of Neuroscience 37, .457– 478 ↩︎
- C Blumeet al. (2015): Across the consciousness continuum—from unresponsive wakefulness to sleep. Frontiers of Human Neuroscience 9, 105, doi: 10.3389/fnhum.2015.00105. ↩︎
- N Block (1995): On a confusion about a function of consciousness. Behavioral and Brain Sciences 18, 227–247.
↩︎ - A Alcaro et al (2017): The affective core of the self: a neuro-archetypical perspective on the foundations of human (and animal) subjectivity. Frontiers of Psychology, doi 10.3389/fpsyg.2017.01424 ↩︎
- A Damasio (2003): Feelings of emotion and the self. Annals of the New York Academy of Science 1001, 253-261. ↩︎
- A Seth (2021): Being You: A New Science of Consciousness. Faber and Faber. ↩︎