THE GREAT MYSTERY OF LIFE: WHERE DID IT COME FROM, WHAT SUSTAINS IT, AND WHERE DOES IT GO WHEN WE DIE? (Chapter 3)
A personal reflection on science, abiogenesis, panspermia, the human body, and the possibility of a soul
By lim ju boo
Introduction: Questions That Science Has Not Yet Fully Answered
Throughout my life, I have been fascinated by the natural world and have tried to understand its workings through scientific inquiry. As a doctor, I have studied the human body and the physiological processes that keep us alive. My degree in zoology from the University of Calcutta gave me another perspective on living organisms, while my short postdoctoral course in biological evolution at the University of Cambridge deepened my interest in how life has developed over geological time. My scientific interests have extended beyond medicine into biology more broadly, including evolution, nature and the diversity of living organisms.
Yet, despite these experiences and the knowledge I have accumulated, one fundamental question continues to trouble my mind: What exactly is life?
I can explain many natural phenomena through physics, chemistry and biology. I can describe how the heart pumps blood, how the lungs exchange gases, how cells produce energy, how enzymes catalyze biochemical reactions, and how organisms grow, reproduce and evolve. I can identify many of the substances that make up a living body and describe the chemical reactions occurring within it.
But when I ask myself what actually makes these substances alive, I find that I cannot provide a complete answer.
Why should a collection of chemicals, arranged under certain conditions, become a living organism capable of maintaining itself, responding to its environment, growing and reproducing? What distinguishes living matter from non-living matter? Is life simply the result of an extraordinarily complex arrangement of physical and chemical processes, or is there some deeper principle that we have not yet understood?
And when a living organism dies, where does its life go? Does it simply cease to exist as a process, or is there something beyond the physical body that science has not yet been able to identify?
These questions have accompanied my reflections for a long time. They are not questions I ask because I reject science. On the contrary, my scientific background is precisely what encourages me to examine them carefully. I want to distinguish what science has demonstrated from what remains uncertain, while allowing myself to consider philosophical and spiritual possibilities without automatically accepting or rejecting them.
I have therefore decided to bring these questions together in this article, not because I possess the answers, but because I believe that the questions themselves deserve serious consideration.
What Do I Mean When I Say That Something Is Alive?
In biology, I learned to recognize the familiar characteristics of living organisms through the mnemonic MRS GREN: movement, respiration, sensitivity, growth, reproduction, excretion and nutrition.
These characteristics are useful for teaching and recognizing life, although no simple checklist perfectly distinguishes every living organism from every non-living system. Some living organisms do not reproduce individually, and dormant organisms may show very little observable activity. Viruses, meanwhile, occupy a disputed boundary because they possess genetic material and evolve but cannot reproduce independently of host cells.
Nevertheless, MRS GREN describes many of the activities associated with life. It helps me identify a living organism, but does it tell me what life itself fundamentally is?
I can observe a seed germinating, a bacterium multiplying, a bird flying, a fish swimming and a human being breathing. I can measure their physiological activities and investigate the biochemical reactions responsible for them. But the observation that something is alive is not necessarily the same as an explanation of how life first emerged.
This distinction troubles me.
If I examine a living cell, I find membranes, proteins, nucleic acids, lipids, carbohydrates, minerals and water. I can identify its genetic material and investigate its metabolic pathways. Yet no single one of these substances, considered in isolation, is what I would ordinarily call life.
The chemicals are indispensable to life as we know it, but the question remains whether life can be understood entirely in terms of the organized activities of those chemicals.
One widely used scientific approach is to regard life as a complex, self-maintaining chemical system capable of evolution through natural selection. Under this interpretation, life is not an additional ingredient placed inside a cell. It is a condition that emerges when matter is organized into a system capable of sustaining the processes associated with living organisms.
This is a useful scientific perspective, but it does not eliminate every philosophical difficulty. It describes life through the organization and behaviour of living systems without necessarily settling the deeper question of why such organization emerged in the first place.
Perhaps I am asking several different questions under the single word life. I may be asking how living systems function, how they originated, what makes them conscious, or whether a spiritual dimension exists. These questions are related, but they are not identical.
Recognizing this may be the first step towards understanding why the mystery seems so difficult to resolve.
Could Life Have Emerged from Non-Living Matter?
One of the most important scientific questions is how the first living systems arose on the early Earth.
The scientific investigation of this problem is known as abiogenesis: the emergence of life from non-living chemical systems. It does not mean that a fully formed organism appeared suddenly out of absolute nothingness. Rather, it investigates whether natural chemical processes could have led, step by step, from simpler substances to increasingly complex systems that eventually acquired the characteristics of life.
The Earth formed approximately 4.5 billion years ago, and evidence indicates that life was present billions of years ago, perhaps as early as about four billion years ago. The precise timing and interpretation of the earliest evidence remain subjects of scientific investigation.
Scientists are exploring several possible environments in which the necessary chemical reactions might have occurred. These include hydrothermal vents on the ocean floor, shallow ponds, hot springs, tidal pools, mineral surfaces and other environments where suitable molecules could accumulate and interact.
The early Earth was not like the planet I see today. Its atmosphere, oceans, geological activity and chemical environment differed substantially from modern conditions. Energy from sunlight, lightning, volcanic activity and chemical gradients may have helped drive reactions among the substances available at the time.
Research has demonstrated that some molecules important to life can form under plausible prebiotic conditions. Certain lipids can assemble into membrane-like structures, and some RNA molecules can catalyse chemical reactions. These findings help researchers investigate how early chemical systems might have acquired some of the properties needed for life.
One influential hypothesis proposes an early stage sometimes called the RNA world. RNA can carry genetic information, and certain RNA molecules can perform catalytic functions. This suggests a possible way in which information storage and chemical activity might have become linked before the modern biological division of labour between DNA, RNA and proteins was fully established.
However, I must be careful not to mistake a plausible hypothesis for a completed explanation.
Scientists have not yet established a complete, experimentally confirmed sequence of events explaining how non-living chemicals became the first living cell. The transition may have involved several interacting stages, and different hypotheses propose different pathways.
NASA's astrobiology programme continues to investigate prebiotic chemistry, the emergence of living systems and the possibility of life elsewhere in the universe. The National Academies of Sciences has likewise described the origin of life as a major scientific problem whose details remain unresolved. (NASA, How Did Life First Emerge on Earth?; National Academies, Genesis: The Scientific Quest for Life's Origin.)
I therefore cannot honestly say that science has already explained exactly how life began.
But I must also distinguish this uncertainty from the claim that life could not have emerged naturally. We do not yet know the complete pathway, and that is different from demonstrating that no natural pathway exists.
The scientific investigation remains open.
Does the Origin of Life Contradict the Conservation of Matter and Energy?
Here my thoughts turn to a principle that is fundamental to physics.
In ordinary physical and chemical processes, matter and energy are transformed and transferred rather than created from absolute nothingness. Einstein's famous equation, (E=mc^2), expresses the relationship between mass and energy.
If the atoms in a living body were already present in the environment, and the energy sustaining its metabolism came from chemical reactions or ultimately from sources such as sunlight, then the materials and energy of life need not have appeared from nowhere.
The deeper problem is not necessarily where the atoms came from, but how they became organized into a living system.
Consider the difference between a heap of bricks and a functioning house. The bricks may be identical in both cases, but their arrangement determines whether they form a usable structure. Even this analogy is limited, because living systems are not merely assembled structures: they actively maintain themselves, regulate their internal conditions and participate in networks of chemical reactions.
Nevertheless, it helps me see that the existence of the necessary materials does not, by itself, explain the emergence of a living organization.
I must also remember that the conservation of matter and energy does not require every arrangement of matter to persist forever. Structures can break down, chemical reactions can cease, and organized systems can lose their capacity to function while their constituent matter and energy continue to undergo transformations.
Thus, I can accept that the material ingredients of life are transformed rather than simply destroyed, while still asking how life originated and what it means for a living system to cease functioning.
These are separate questions, and the conservation laws alone do not settle all of them.
Could Life Have Arrived on Earth from Somewhere Else?
If I cannot yet understand exactly how life began on Earth, another possibility naturally comes to mind.
Could life have originated elsewhere in the universe and subsequently been transported to our planet?
This possibility is known as panspermia. In its broadest form, it proposes that life, or material capable of contributing to life, may have travelled between celestial bodies.
For example, meteorites originating from Mars have reached Earth, demonstrating that rocks can be transferred naturally between planets. Under suitable circumstances, material ejected from one world might travel through space and eventually land on another. Researchers have therefore investigated whether certain microorganisms or biological materials could survive some stages of such a journey.
The idea is not inherently impossible in every form, but important difficulties remain. A viable organism would have to survive the conditions associated with ejection from its original environment, radiation and exposure during transit, and the eventual arrival and establishment in a suitable habitat. The feasibility would depend on the organism, the route, the duration and the environmental conditions involved.
There is, however, a crucial distinction between transporting the building blocks of life and transporting life itself.
Organic molecules can form through non-biological chemistry and have been found in extraterrestrial materials. Their presence does not demonstrate that living organisms travelled to Earth. Similarly, evidence that rocks can travel between planets does not establish that those rocks carried viable organisms.
No confirmed evidence currently demonstrates that life arrived on Earth from another world.
Nevertheless, I find the question intellectually fascinating because it broadens the investigation beyond our own planet.
If life were discovered on Mars, Europa, Enceladus or a planet orbiting another star, scientists would need to determine whether it shared a common origin with terrestrial life or arose independently. Such a discovery could transform our understanding of how frequently life emerges in the universe.
NASA and other research organizations continue to investigate these possibilities, but extraterrestrial life has not yet been conclusively detected. (NASA Astrobiology, About Astrobiology; SETI Institute, Frequently Asked Questions.)
For now, panspermia remains a hypothesis rather than an established explanation for the origin of terrestrial life.
If Life Came from Another World, Where Did It Begin There?
This is where my questioning becomes even more persistent.
Suppose, purely for the sake of argument, that life did arrive on Earth from another planet, moon or distant region of the universe. Suppose further that it was carried here by a meteorite, a comet, dust or some other means of transport.
Would that solve the mystery of life's origin?
Not necessarily.
It would explain one possible way in which life reached Earth, but it would not automatically explain how life originated in the place from which it came.
I would simply have moved the question from Earth to another world.
If life originated on Mars, I could ask how it began on Mars. If it originated on an icy moon, I could ask how it began there. If it arrived from a planet orbiting another star, I could ask how the first living system emerged on that planet.
And if someone proposed that life came from a still more distant world, I would have to ask the same question again.
Transporting life from one place to another does not, by itself, explain the ultimate origin of life.
Panspermia could eventually prove important in explaining the distribution of life throughout the universe. But unless the transported life originated through some process already understood, the original question would remain.
Did life begin naturally from non-living matter in that other environment? Did it have some other origin? Is there a process we have not yet discovered?
At present, I have no definitive answer.
I also cannot rule out the possibility that life originated independently on more than one world. If that happened, comparing different forms of life might reveal which characteristics are universal to living systems and which are peculiar to life on Earth.
But until extraterrestrial life is confirmed, these possibilities remain subjects for investigation rather than established facts.
I find myself returning to the same fundamental question, wherever I place the beginning: what was the first process that produced a living system?
The Stardust in My Body and the Origin of Life
There is another aspect of this question that I find deeply moving.
The atoms in my body have a history that extends far beyond my own lifetime. Many of the elements essential to life were produced through processes occurring in earlier generations of stars, while some of the lightest elements have origins dating back to the early universe.
The carbon in my body, the oxygen I breathe and the calcium in my bones belong to a cosmic history that preceded the appearance of human beings by billions of years.
In this material sense, I am made from substances that have passed through the long history of the universe.
But I must distinguish the cosmic origin of life's ingredients from the origin of life itself.
The fact that the elements in my body were formed through cosmic processes does not explain how they became organized into living cells. The presence of carbon, oxygen, nitrogen, phosphorus and other essential elements does not automatically produce an organism.
The ingredients and the living organization are related, but they are not the same question.
This is why I find the phrase we are made of stardust both scientifically meaningful and philosophically evocative. It reminds me that I am physically connected to the universe, yet it does not tell me everything about what it means to be alive.
My Lamp Analogy: What Is the Flame That Makes the Difference?
To help me think about this problem, I often imagine an oil lamp.
The lamp has a physical structure. Its wick provides a place for combustion to occur, the oil supplies chemical energy, and oxygen from the air supports the reaction. When these conditions are suitable, a flame appears and emits light and heat.
If the oil runs out, the wick is damaged or the oxygen supply is interrupted, the flame goes out.
Where does the flame go?
I do not ordinarily imagine that the flame is a tiny object that detaches itself from the lamp and travels elsewhere. The combustion process ceases, and the energy released during the process is transferred to the surroundings as heat and light. The substances involved undergo chemical transformations.
Could life be understood in a somewhat similar way?
The physical body provides the structure. Nutrients supply chemical energy and raw materials. Oxygen supports the metabolism of many organisms. Enzymes, membranes, genetic information and countless interacting biochemical pathways sustain the living system.
When these processes become irreversibly disrupted, the organism can no longer maintain its integrated functioning.
The analogy helps me understand how a process can begin, continue and cease without requiring a separate material object to depart from the system.
However, I must not stretch the analogy too far. A flame is not a living organism. It does not maintain a complex biological organization, reproduce through genetic inheritance or evolve through natural selection. Living systems are far more sophisticated.
Nor does the lamp analogy prove that a soul does not exist. It simply illustrates one possible way to understand life as an organized process rather than as a separate physical substance.
My remaining question is whether this biological account explains everything about life or whether there is a spiritual dimension that lies beyond it.
The analogy cannot decide that question for me.
Why Is a Piece of Beef Not Alive Like the Animal It Came From?
Another question that occurs to me is why a piece of beef can contain many of the same chemical substances that were present in the living animal, yet no longer constitutes a living organism in the same sense.
Beef contains proteins, fats, water, minerals, amino acids and other molecules. Many of these substances are also present in the living tissues of the animal from which the meat came.
What has changed?
The most important difference is not simply the presence or absence of particular chemicals. It is the loss of the integrated organization and functioning of the organism as a whole.
After slaughter, circulation and the coordinated physiological activities that sustained the animal cease. The cells do not all die simultaneously. Some cellular processes continue for a time, and post-mortem biochemical changes occur. Eventually, tissues deteriorate, and decomposition begins.
A piece of meat can therefore contain cells that remain metabolically active for a limited period, even though the animal as an integrated living organism has died.
This is an important distinction. Death is not necessarily an instantaneous disappearance of every biological process. Rather, it involves the irreversible loss of the functions necessary to sustain the organism as a whole.
The example of beef helps me understand why the chemical ingredients alone are insufficient to define life. The same broad classes of molecules can exist in living tissues and in tissues that no longer belong to a functioning living organism.
But it does not, by itself, establish whether a soul exists or whether something spiritual has departed. It demonstrates a difference in biological organization and function, not the presence or absence of an independently measured spiritual entity.
When My Heart Stops, What Happens to the Life Within Me?
As a research scientist and doctor, I find this question especially difficult to ignore.
When the heart stops pumping blood effectively, circulation fails. The brain and other organs lose their normal supply of oxygen and metabolic substrates. Cells become unable to maintain their usual energy balance, ion gradients deteriorate, and cellular functions become impaired.
If circulation is restored promptly, some of these changes may be reversible. This is why cardiac arrest does not invariably mean irreversible death. When circulation cannot be restored and the injury becomes irreversible, the integrated functions of the organism can no longer be recovered.
Different tissues lose their functions at different rates. The process is not a single switch that turns every cell off at exactly the same moment.
I can explain much of this through physiology and biochemistry. I can describe how oxygen deprivation affects the brain, how energy production fails and how cellular membranes lose their integrity.
But the philosophical question that follows is more difficult.
If there is a life force, spirit or soul that gives life to the body, why does it not leave when the heart stops? If it does leave, where does it go? Does it remain somewhere beyond the body, or does it enter another organism?
These questions cannot be answered simply by observing a stopped heart.
From the scientific perspective, the cessation of circulation and the eventual loss of integrated biological functioning can be studied through physical measurements. We do not, however, possess an established scientific measurement demonstrating that a separate entity called the life force or soul leaves the body at death.
From a religious or spiritual perspective, death may be understood as the departure of the soul or spirit, depending on the tradition and its interpretation of the relationship between body and soul.
These are different approaches to the question.
I can acknowledge that the physiological explanation is well supported without claiming that it resolves every metaphysical question about human existence. At the same time, I cannot claim that the absence of a scientific measurement proves the existence of a soul.
My honest position is that I do not know whether an independently existing soul departs from the body at death, and I do not know where it would go if it did.
That uncertainty is precisely what makes the question so persistent in my mind.
Does the Life Force Have to Be a Form of Energy?
It is tempting to think that if life is sustained by an invisible force, that force must be some kind of energy.
After all, living organisms depend on energy. Muscles contract, nerves transmit electrical signals, cells maintain chemical gradients, and metabolism involves the transfer and transformation of energy.
But the energy used by these processes is not the same thing as a mysterious substance called life.
Biology and physics can measure many forms of energy involved in living organisms. Yet no distinct, universally accepted physical energy corresponding to a separate soul or life force has been identified.
If I propose that such a force exists, I must ask what properties it has, how it interacts with the body and whether its effects could be observed or measured. Without answers to these questions, the idea remains a philosophical or spiritual hypothesis rather than an established physical explanation.
This does not settle whether a soul exists. It simply means that I cannot identify it with physical energy merely because energy is essential to life.
Einstein's equation, (E=mc^2), describes a relationship between mass and energy. It does not establish that consciousness, personal identity or a soul is a form of energy that survives bodily death.
When a body dies, its physical matter remains and its energy is transferred or transformed through physical and chemical processes. But the conservation of energy does not tell me whether the person's individual consciousness or spiritual identity continues.
I must keep these questions separate if I want to reason carefully.
Can Life Disappear Without Leaving Any Trace?
In one sense, life does leave traces.
When an organism dies, its body undergoes physical, chemical and biological transformations. Its tissues may be consumed by other organisms, decomposed by microorganisms or incorporated into the soil and surrounding environment. Its elements can eventually become part of other living systems.
In this material sense, the components of the organism do not simply vanish.
Biological life also continues through reproduction. Genetic information passes from parents to offspring, and populations persist and evolve across generations. Nutrients and chemical elements move through ecosystems, connecting living organisms in cycles of matter and energy.
But these processes do not establish that the individual life of a deceased organism transfers into another body.
The carbon from a dead human body might eventually become part of a plant. The plant might be eaten by an animal. The animal's body might then contain atoms that were once part of the human body.
This is a physical and ecological transfer of matter, not evidence that the original person's consciousness or soul has moved into the plant or animal.
The distinction matters because I do not want to confuse the continuity of matter with the continuity of personal identity.
A person is more than a collection of atoms considered separately. Personal identity involves the organized history and functioning of a particular human being, including the brain processes associated with memory, personality and consciousness.
Whether any aspect of personal identity continues beyond bodily death is a different question, one that physical recycling alone cannot answer.
What About the Soul, Spirit and Breath of Life?
My scientific curiosity does not prevent me from considering religious and philosophical interpretations of life.
In fact, I find that they often address questions that arise naturally when I reflect on the limits of scientific explanation.
In the biblical account in Genesis 2:7, God forms the human from the dust of the ground and breathes into him the breath of life, after which the human becomes a living being. I find this image powerful because it connects the physical materials of the human body with life understood as a gift from God.
Different Christian traditions interpret the soul, spirit and breath of life in different ways. Some emphasize a soul that continues after bodily death; others distinguish different aspects of human nature in more complex ways. I should therefore avoid assuming that every Christian tradition teaches exactly the same thing.
Other religious and philosophical traditions also offer different accounts of life and death. Some speak of reincarnation, others of an afterlife, resurrection or another form of spiritual continuation. These beliefs cannot all be treated as identical, and their truth cannot be settled merely by comparing their terminology.
I am interested in these ideas because they address my concern that human existence may not be exhausted by a description of the body's physical components.
But I must also recognize the limits of what I can establish. A religious text may provide a framework for belief and meaning, but it is not a laboratory measurement of a soul. Similarly, a scientific explanation of cellular death does not, by itself, prove or disprove every theological claim about life beyond death.
I can explore both perspectives while remaining honest about the different kinds of evidence they employ.
For me, the question is not whether I must choose between scientific curiosity and spiritual reflection. It is whether I can pursue both without confusing a hypothesis with a demonstrated fact.
Could Consciousness Be the Missing Piece?
There is another question that may be related to my search for the nature of life: the mystery of consciousness.
I know that the brain is a physical organ. Its neurons communicate through electrical and chemical processes, and brain activity is closely associated with perception, memory, emotion, reasoning and conscious experience.
Changes in the brain can profoundly affect personality, memory, awareness and behaviour. These observations provide strong reasons to investigate consciousness through neuroscience.
Yet there remains a philosophical question about subjective experience: why and how should physical processes be accompanied by the inner experience of seeing a colour, feeling pain, remembering a loved one or being aware of one's own existence?
Scientists have made considerable progress in identifying neural processes associated with conscious states, but the relationship between physical activity and subjective experience continues to be debated.
Some philosophical positions interpret consciousness as arising entirely from physical processes. Others argue that consciousness requires a different conceptual explanation, and some propose that mind or consciousness has a more fundamental role in reality.
The existence of these debates does not prove that a soul exists. Nor does the fact that consciousness is difficult to explain establish that it is supernatural.
It does, however, show why I should distinguish the question of biological life from the question of conscious experience.
A bacterium can be alive without evidence that it possesses human-like consciousness. A person can temporarily lose consciousness while remaining biologically alive. And the question of whether personal consciousness continues after irreversible death is more difficult still.
Perhaps part of my persistent uncertainty comes from trying to answer all these questions through one concept called the life force or soul.
It may be more fruitful to investigate them separately before deciding how they might be connected.
If Science Cannot Measure the Soul, Does That Mean It Does Not Exist?
This is a question I must approach with particular care.
Science depends on observation, measurement, experiments, reproducibility and the development of explanations that can be tested against evidence. When a claim concerns an entity that supposedly interacts with the physical body, scientists can ask whether that interaction produces detectable effects.
However, the absence of an established measurement does not automatically prove that a proposed entity is impossible. It means that the claim has not been established through the relevant scientific evidence.
There is a difference between saying, "Science has not demonstrated that a soul exists," and saying, "Science has proved that no soul can exist."
The first statement describes the present evidential situation. The second makes a much broader claim that would require its own justification.
I therefore do not think it is necessary for me to dismiss every spiritual possibility simply because I cannot measure it. But neither should I conclude that an invisible soul must exist merely because I cannot explain every aspect of life or consciousness.
The honest position is to recognize the limits of my knowledge.
If I believe in a soul because of religious faith, philosophical reasoning or personal conviction, I should acknowledge the basis of that belief. If I make a scientific claim, I should be prepared to ask what evidence supports it and what observations might count against it.
This distinction allows me to remain open-minded without abandoning scientific discipline.
What, Then, Is the Ultimate Origin of Life?
After considering abiogenesis, panspermia, the cosmic origin of the elements, cellular biochemistry, the lamp analogy, death and the possibility of a soul, I find myself returning to the original question.
What is the ultimate origin of life?
There are several possibilities worth considering, but they have different evidential status.
The first is that life emerged from non-living chemistry on the early Earth. This is the subject of abiogenesis research, which has produced important insights into prebiotic chemistry but has not yet established a complete pathway to the first living system.
The second is that life, or material contributing to its emergence, arrived from elsewhere in the universe. Panspermia remains a possibility under investigation, but there is no confirmed evidence that life arrived on Earth from another world. Even if it did, its original origin would still need to be explained.
The third is that life exists elsewhere and may have originated independently on other worlds. The immense number of planets in the universe makes the search worthwhile, but the existence of extraterrestrial life has not yet been confirmed.
The fourth is a philosophical or theological interpretation in which life ultimately depends on a divine source or a reality beyond the physical universe. This may provide meaning within a religious worldview, but it is not an experimentally established explanation of the biochemical origin of the first cell.
I cannot honestly declare one of these possibilities to be a complete answer to every question I have asked. Nor should I treat them as though they are all equally supported by scientific evidence.
Instead, I can recognize what each proposes, examine what it explains and identify what remains unresolved.
Perhaps future research will show that the emergence of life is a natural process that occurs wherever suitable conditions persist. Perhaps life is rare and requires an unusual combination of circumstances. Perhaps discoveries elsewhere in the universe will transform our understanding of biology. And perhaps some of the philosophical questions I ask will remain distinct from the questions that experiments can answer.
At present, I do not know.
My Final Reflection: I Am Still Searching
After years of scientific learning, I find myself in a position that may seem paradoxical. I know more about the mechanisms of life than I did when I began my studies, yet the deeper mystery continues to occupy my thoughts.
I know that my body is composed of atoms and molecules. I know that its cells depend on biochemical reactions, that its organs function through complex physiological systems, and that the interruption of essential processes can lead to irreversible death.
I know that the matter and energy associated with my body undergo transformations rather than simply disappearing. I know that biological life continues through reproduction, evolution and the cycling of materials through the natural world.
But I do not know exactly how non-living matter first became organized into life. I do not know whether life originated on Earth or whether some of its earliest ingredients, or even living organisms themselves, arrived from elsewhere. I do not know whether a soul exists independently of the body, and I cannot identify a scientifically established destination to which such a soul might go after death.
These are the limits of my present understanding.
I do not consider that admission a failure of science. On the contrary, recognizing what remains unknown is an essential part of scientific honesty.
My studies in medicine, zoology, biological evolution among other scientific specialties have taught me to investigate living systems. My interest in biological evolution has encouraged me to look beyond individual organisms and consider the long history of life. My spiritual reflections lead me to ask whether the meaning of life extends beyond the physical processes I can observe.
I want to pursue these questions without pretending that I have already discovered the answers.
Perhaps the greatest difficulty is that the word life seems so familiar. I use it every day, observe it everywhere and understand many of its manifestations. Yet when I ask what life fundamentally is, the familiar suddenly becomes mysterious.
I can describe a living organism, explain many of its functions and investigate the processes that cause it to die. But the ultimate origin of the first living system and the possibility of personal existence beyond death remain questions that I cannot resolve merely by listing biochemical reactions.
I am therefore left with two forms of inquiry: the scientific investigation of the physical world and the philosophical or spiritual reflection on what that world means.
I do not wish to use the second to replace the first, nor do I wish to pretend that the first has already answered every question raised by the second.
I want to continue asking, learning, examining and reflecting.
And perhaps this is the most honest conclusion I can reach: I do not yet know what life ultimately is, where it first originated, or whether anything of the individual person survives bodily death.
I remain a student of the mystery of life, not because I have found all the answers, but because I have not yet found a reason to stop asking the questions.
If this article encourages other readers to pause and reflect on the nature of their own existence, to distinguish knowledge from assumption, and to approach both science and spirituality with humility, then the exercise will have been worthwhile.
For now, the mystery remains—and so does my curiosity.
Selected references for further reading
1. National Academies of Sciences. Genesis: The Scientific Quest for Life's Origin. Joseph Henry Press, 2005. https://doi.org/10.17226/10753
2. NASA Science. How Did Life First Emerge on Earth? NASA Astrobiology learning resource. https://science.nasa.gov/astrobiology/learning-resources/alp/how-did-life-first-emerge-on-earth/
3. NASA Science. Astrobiology at NASA. https://science.nasa.gov/astrobiology/at-nasa/
4. NASA Astrobiology. About Astrobiology. https://astrobiology.nasa.gov/about/
5. SETI Institute. Frequently Asked Questions. https://www.seti.org/about/faq
These references provide scientific background on origin-of-life research and the search for extraterrestrial life. They do not establish a scientific explanation for the existence of life elsewhere
