Since ancient times, the concept of Soul has been used to try to give an explanation to the fact that we are not only “body and matter”, but we have something in us that goes beyond the tangible.
The word soul derives from the Latin anima which in turn derives from the Greek ànemos, which means "breath", "wind" and describes the spiritual part, the present but intangible essence of the human being. The term soul is also sometimes used as a synonym of psyche, wanting to indicate with this term both the set of our affective, intellectual and cognitive capacities - our Consciousness - and the instinct and the unconscious, which are "qualities" unavoidable from our “human being”.
The soul has a primary role in the great monotheistic religions, as it is what remains of us after death, it is our immortal part that will continue the journey towards judgment and final catharsis.
In Eastern religions, especially in Hinduism, the term Ātman is used, a Sanskrit term that indicates the "essence" or the "vital breath" of man and can be translated with the reflexive pronoun Self, and it is what will survive through the various Karmic cycles.
Even in the pre-Christian religions from which the following ones have taken inspiration, such as Zoroastrianism and Mithraism, there existed the concept of the soul and of a path that it had to perform to be judged after death.
The concept of Soul, as well as that of Spirit, over time has always been inextricably linked to religion and that is why Science has always snubbed it, relegating it to aleatory matter not subject to investigation, if not to mere superstition. The study of the soul is pertaining to metaphysics, while physics deals with the tangible.
This paradigm, however, seems to be scratched by the latest scientific discoveries and especially by the advent of quantum physics, which, wanting to simplify, connects science with the invisible, describing the behavior of matter with a series of laws that go beyond the "corporality" of the matter itself.
In fact, the foundation of quantum mechanics is the description of particles and radiations both as undulatory phenomena and as particle entities, as opposed to the vision of classical mechanics that described matter only as composed of particles and light only composed of waves.
The wave-particle duality can be applied to any aspect of matter and also to our cells, in particular brain neurons, which, from the quantum point of view, could represent the "seat" of our Soul. From this observations come the concept of quantum brain, coined following several discoveries in the field of neurobiology occurred in the nineties.
In this period the English physicist Roger Penrose and the American neuroscientist Stuart Hameroff developed a theory called ORCH-OR (orchestrated objective reduction), according to which the human mind functions as a quantum computer. There are neuronal structures (also present in other cells) called microtubules which, comparable to qubits of quantum computers (the qubit represents the unit of quantum information), can occur in different quantum configurations depending on the cognitive processes in place. Moreover, these microtubules would all be quantally correlated and their mutual interaction would create that phenomenon which we call "consciousness".
Later, in 2012, two Austrian scientists showed that the ion channels present on neurons (responsible for neuronal activation and inhibition) also behaved in a "quantum" way (i.e. as waves generating a magnetic field) and hypothesized their involvement in "Phenomena of generation of consciousness".
Starting from these bases and other similar works, in a somewhat counterintuitive way, the Soul can also be explained in neurobiological and quantum terms.
It is a subjective and individual entity and would seem the result of a mental activity without any inhibition in which spatial and temporal information is lacking; it is amorphous and immaterial but can become conscious through "reduction" phenomena.
Our consciousness - our Self - would seem to be the result of three evolutionary stages.
In a primitive stage, our mental activity is completely uninhibited and includes only the primary needs of the organism and perceives itself and the world as one. In a second stage some mental processes are inhibited and the mind gains awareness of itself and the surrounding world and begins to perceive “itself as a self” regarding the surrounding matter. The third and hierarchically final stage of self development (reflective self) is related to higher cortical functions, such as memory, executive functions, self-control, mentalization, metacognition, and other complex cognitive abilities.
What would cause the "ascent" of consciousness through these three stages would be an inhibition, a "reduction" as we grow in mental activity. If this reduction in activity were not carried out, we would be under the constant influence of a river of stimuli and we would not be able to pay attention to any task. This inhibition does not happen in a clear way but through a series of steps: there is a reduction first to unconscious mental events and then to conscious mental events, gradually acquiring a conception of time and space. This reduction process is parallel to the maturation of the frontal cortex of the brain and of γ-aminobutyric acid (GABA), which as an excitatory neurotransmitter during the prenatal life of the fetus, becomes the main inhibitory neurotransmitter in the course of adult life.
The inhibitory activity of GABA and prefrontal cortex makes the Soul conscious, but it can return unconsciously when this inhibition decreases. Examples of inhibitory mental activity may come from the perceptual differences of a newborn, from individuals subjected to mental dissociation phenomena and from individuals under the influence of psychedelic drugs, particularly mescaline and DMT. In all three examples mentioned above the mental inhibitory processes have been interrupted and they share the same perception of the self and the Soul: a world without time and without space, perceived as a whole and caused by uninhibited mental activity.
Therefore, according to this theory the Soul is both the source of unconsciousness and of consciousness. The Soul contains mental energy to fill the brain, but must first be "reduced", that is, its activity must undergo an inhibition to become a cognitive function of the brain. This happens in stages: we start from the unconscious, then deep unconscious, dynamic unconscious and preconscious. In the final phase, the soul is further inhibited and becomes awareness. The nonphysical soul thus acquires some physical properties when it is "reduced" to consciousness in the brain. The nonphysical soul can best be described by the rules of quantum physics, while the physical soul (the brain) is best described by the rules of classical physics.
Finally, since it is now clear that the Universe is based on the rules of quantum physics, between the structures of the Universe and those of our brain could exist many "quantum" similarities that make us all, at least at the unconscious level, part of the One. This could also give credit to the theory of a conscious intelligence that pervades the Universe and that in other times would be called God, beyond all the theological implications that this word carries with it.
The soul is not material; rather, it is energy. In its energetic form, it can extend to infinity. The soul is indeterminate and is open to many possibilities; using mechanical physics, we make it closed and predictable. We go beyond physics, but we can not perceive it because our perception itself depends on physics.
Sources:
Orchestrated objective reduction of quantum coherence in brain microtubules: The" Orch OR" model for consciousness. S Hameroff, R Penrose - Mathematics and computer simulation, 1996.
A quantum-mechanical description of ion motion within the confining potentials of voltage-gated ion channels. J Summhammer, V Salari et al.- Journal of integrative neuroscience, 2012
The Soul, as an Uninhibited Mental Activity, is Reduced into Consciousness by Rules of Quantum Physics. Ceylan, M.E., Dönmez, A., et al. Integrative psychal behaviour, 2017