The Human Spirit Viewed Under Scientific Microscope

by Prof. Uchenna Nwosu

Since time immemorial, homo sapiens has perceived himself as possessing a detachable essence variably described as spirit, soul, or psyche. Believed to be resident in the heart or mind, it continues to live after death in a kingdom administered by multiple gods in ancient religions, and one God in modern Abrahamic faiths. Doctrines of religion have been enunciated assuaging the homo sapiens’ fear of death by promise of returning to earth through the reward of reincarnation for a well-lived life on earth, or of the resurrection of the body and final judgment, leading either to the resumption of eternal life in heavenly Paradise for the righteous, or eternal hellfire for those who lived unjust lives.

This construal of the spirit/soul/psyche is, in fact, a product of awareness of the human brain whose prefrontal cortex, in proportion to the whole brain, is by far larger than those of other animals. The center of awareness uniquely located therein is so highly developed that only the human being possesses a subjective awareness in the three dimensions of space, time and person.

This writeup is an attempt to view, under the scientific microscope, that essence of human existence variously called spirit in everyday life, the soul in reference to Theology, and psyche in Psychology.

The Oxford Dictionary defines the spirit as the non-physical part of a person which is the seat of emotions and character, and capable of surviving physical death or separation. It also describes the soul and psyche in more or less similar terms. It further states that, in folklore, some spirits are supposed to be entirely independent of human existence, e.g., a demon, ghost, fairy, or angel. This scientific scrutiny excludes the latter group. Furthermore, it regards the spirit, soul, and psyche as interchangeable.

The spirit is viewed, in science, as epiphenomenal to, or abstraction of the brain activity manifesting as emotions (such as love, hate, anger, sacrifice, happiness, satisfaction) which though experienced, have no physical reality. The emotions are experienced from thoughts, which are actions-in-rehearsal of fleeting scenarios on the brain “stage” (alias the mind). These actions-in-rehearsal or thoughts are created by the various permutations and combinations of interactions of assorted chemical messengers called neurotransmitters, the principal ones being oxytocin, serotonin, acetylcholine, dopamine, norepinephrine, gamma-aminobutyric acid (GABA) and glutamate. The neurotransmitters transfer electrical signals from cell to cell across gaps at cell junctions of specialized interconnecting brain nerve cells called neurons.

Neurotransmitters are endogenous, i.e., manufactured within the neurons themselves. While some, like glutamate, excite transfer of these electrical impulses, others, like GABA, inhibit them. Yet others like dopamine serve to modulate the electrical transmissions. It should be noted that neurotransmitters, so far, identified, number over 40. Thus, the spirit is surmised as epiphenomenal to the constant flux of the brain neurotransmitter activities occurring in real-time in various permutations and combinations. These fluxes are influenced by external input from our sense organs (eyes, ears, mouth and skin), as well as internal inputs from our body organs and memory, to form the actions-in-rehearsal or thought scenarios, which may or may not be acted out by the physical body via the mechanism of neurologically controlled target organs of the body.


Prof. Uchenna Nwosu (Odenigbo Igboukwu), a Specialist Obstetrician & Gynecologist, is the founder of Apex Medical Center and Allied Medical Services. In retirement, he owns and operates the Odenigbo Art Gallery, Igboukwu.

Certain exogenous substances (i.e., substances not found naturally in the human body) have been discovered to possess some levels of neurotransmitter properties. Using these substances as mind-altering drugs has formed the basis of neuropsychopharmacology. Thus have been scientifically synthesized in the laboratory the inhibitory or sedative drugs like the benzodiazepines, of which valium is an example. Excitatory drugs like Zoloft and Prozac have also been scientifically synthesized and used to treat depression.


A drug such as ketamine, which is ordinarily used for anesthesia during surgical operations, has been found to have a dissociative effect on the mind stage, meaning that it can take the neurotransmitter fluxes out of the brain into the external space. In that sense, ketamine can “remove” the mind from the living body, thereby causing the out-of-body experience similar to those reported by some who have reached the threshold of death and then recovered.


Some chemical substances like cocaine and heroin with known neurotransmitter properties alter the mind by interfering with the modulation of the endogenous neurotransmitters of the brain, thereby temporarily creating a mindset of euphoria, a feeling or state of intense excitement and happiness. Unfortunately, most of those drugs are highly addictive, meaning that abusers must subject themselves to increasing doses of the substance to achieve the original effect. Failure to keep increasing the subsequent dose will result in a very unpleasant physical illness known as the Withdrawal Syndrome. However, increasing side effects come with the increasing doses. For a drug like morphine or heroin, the side effect is depression of oxygen intake into the lungs which, if untreated, may lead to death.

Prof. Uchenna Nwosu
Odenigbo Igbo-Ukwu