FROM NON-LIVING MATTER TO LIVING ORGANISMS: CAN SCIENCE EXPLAIN THE ORIGIN OF LIFE, AND COULD GOD BE ITS ULTIMATE SOURCE? (Chapter 5)
by lim ju boo. Chinese name: lin ru wu (林 如 武)
A final personal reflection on the historical theories of life's origin, biological evolution, and the relationship between scientific inquiry and faith in God
A question that continues to trouble me since I began writing this series of my thoughts .
I have said I have spent much of my life trying to understand the natural world through science. I have studied the physiology and biochemistry of the human body as part of medicine. My additional degree in zoology introduced me to the extraordinary diversity of living organisms, and my postdoctoral studies in biological evolution deepened my interest in the history and development of life on Earth.
Yet, despite all these experiences, one fundamental question continues to trouble me: where did life ultimately come from?
I can explain many of the processes by which living organisms function. I can describe how cells obtain energy, how enzymes catalyze biochemical reactions, how genetic information is transmitted and how organisms reproduce and evolve. I can identify many of the chemical substances that constitute living bodies. I can describe all the above in great technical details.
But when I ask how non-living matter first became organized into something alive, I find myself confronting a question that science has not yet completely answered.
Over the centuries, numerous philosophers and scientists have proposed explanations. Some believed that organisms could arise spontaneously from decaying matter. Others investigated whether organic molecules could form naturally on the early Earth. Still others proposed that life might have arrived from outer space, originated around deep-sea hydrothermal vents, or developed through chemical interactions involving mineral crystals.
These ideas differ considerably, and some early theories have been disproved. Others remain active research hypotheses. None has yet produced a universally accepted, complete explanation of the transition from non-living chemistry to the first living system.
But I want to ask a question that goes beyond comparing these scientific proposals.
Even if science eventually discovers exactly how the first living organism emerged from non-living matter, would that necessarily answer the ultimate question of why life exists at all? Could the natural processes investigated by scientists be compatible with my personal belief that God is the ultimate source of life? Over the years a still small voice keeps asking me to read the second verse in Genesis of the Bible for the answer. I subsequent poured out my conscience in Chapter 4 here:
Did God Infuse Life into the Primordial Oceans?
https://scientificlogic.
I do not ask these questions because I wish to reject science. I ask them because I want to understand what science has established, what remains uncertain, and where philosophical or theological reflection begins.
My purpose in this article is therefore not to declare that I have solved the mystery of life. It is to examine the historical and scientific explanations, consider their limitations, and explore whether scientific understanding and belief in God must necessarily be regarded as opposing views.
The Ancient Belief in Spontaneous Generation
For much of human history, people believed that living organisms could arise directly from non-living matter. This idea became known as spontaneous generation.
The belief seemed reasonable when judged by everyday observations. Maggots appeared on rotting meat, insects emerged from decaying vegetation, and microorganisms became visible in food or liquid left standing for a period of time. Without knowledge of microbial contamination, eggs, larvae and the reproductive cycles of many organisms, it was easy to imagine that life was generated directly by decaying substances.
The Greek philosopher Aristotle, who lived from 384 to 322 BCE, accepted that some organisms could arise spontaneously from non-living materials under suitable conditions. His views influenced natural philosophy for many centuries.
However, the historical theory of spontaneous generation must be distinguished from modern research into the origin of life. The ancient belief concerned organisms appearing under ordinary conditions, such as maggots supposedly arising directly from rotting meat. Modern abiogenesis research asks a much more specific question: how could the first living systems have emerged from non-living chemistry on the early Earth, billions of years ago?
The distinction is important because disproving the old belief does not automatically disprove the possibility of life's original emergence through chemical evolution. (OpenStax, Microbiology, section on spontaneous generation.)
Francesco Redi, Lazzaro Spallanzani and Louis Pasteur: The Triumph of Experimental Evidence
One of the most instructive episodes in the history of biology is how the traditional belief in spontaneous generation was challenged through controlled experiments.
In the seventeenth century, the Italian physician Francesco Redi conducted experiments using meat placed in containers. Some containers were left open, while others were covered or sealed. He observed that maggots developed where flies could reach the meat and lay their eggs, whereas the covered meat did not produce maggots in the same way.
His findings challenged the belief that maggots arose directly from the meat itself. They demonstrated that an apparent example of spontaneous generation could be explained by the reproductive activities of existing organisms.
Later, Lazzaro Spallanzani investigated microbial growth in broth. By heating broth and sealing containers to prevent contamination, he found that microbial growth could be prevented under those conditions. His work contributed to the growing evidence that microorganisms did not simply appear in sterile broth without an external source of contamination.
In the nineteenth century, Louis Pasteur conducted influential experiments using swan-neck flasks. He boiled nutrient broth to sterilize it, then allowed air to enter through curved necks that trapped dust and microorganisms. The broth remained free of microbial growth while contamination was prevented. When the broth was exposed to trapped particles or otherwise contaminated, microbial growth could occur.
Pasteur's work helped establish that microorganisms in ordinary circumstances arise from pre-existing microorganisms rather than appearing spontaneously in sterilized broth. His experiments were central to the rejection of classical spontaneous generation.
This history offers an important lesson. Scientists should not accept a proposed explanation merely because it appears plausible. They must examine it through careful observation, experimental controls and evidence.
However, I must return to the distinction already mentioned. The experiments of Redi, Spallanzani and Pasteur addressed the supposed spontaneous appearance of organisms under the conditions they investigated. They did not recreate the early Earth, nor did they establish that life could never have originated from non-living chemistry under ancient conditions.
The scientific principle that life today comes from pre-existing life is known as biogenesis. The question of how the first life arose remains a separate problem.
In other words, demonstrating that maggots come from fly eggs does not, by itself, explain how the earliest living systems originated billions of years ago.
Oparin and Haldane: Could Life Have Emerged Through Chemical Evolution?
During the twentieth century, scientists began to investigate the possibility that the first living systems emerged through a long sequence of chemical changes rather than appearing as complete organisms.
The Russian biochemist Alexander Oparin developed an influential hypothesis in the 1920s. Independently, the British scientist J. B. S. Haldane proposed related ideas in 1929.
Their proposals suggested that the early Earth may have provided conditions in which relatively simple substances reacted to form organic compounds. Over time, these compounds could have accumulated, interacted and formed increasingly complex chemical systems.
This general approach became associated with the idea of a primordial soup: an environment in which organic building blocks formed and participated in further reactions.
It is important to recognize that the early Earth's atmosphere may not have had exactly the composition originally assumed in these proposals. Modern research considers several possible environments and chemical pathways rather than relying on one universally accepted scenario.
Nevertheless, the fundamental idea of chemical evolution remains important: the first living systems may have emerged through a sequence of natural chemical processes, with no requirement that a complete modern cell appear suddenly.
The Oparin–Haldane hypothesis helped establish origin-of-life research as a subject for scientific investigation. It did not, however, demonstrate every step leading from simple molecules to a living organism.
Miller and Urey: Can Organic Building Blocks Form Naturally?
In 1953, Stanley Miller, working under the guidance of Harold Urey, conducted an experiment inspired by ideas about the chemistry of the early Earth.
Their apparatus circulated gases and water vapour through a system in which electrical sparks simulated lightning. After the system had operated, the researchers found that several organic compounds, including amino acids, had formed.
The experiment was significant because it demonstrated that certain organic building blocks could be produced from simpler substances under the experimental conditions used.
But Stanley Miller experiment did not create life. It did not produce a complete cell, a self-sustaining organism or a demonstrated pathway to the first living system. He merely showed he could create some organic compounds similar to those found in living things but without life in them. This is almost similar to creating the juice from a piece of dead beef.
The gases he used in the original experiment represented one proposed model of the early atmosphere. Subsequent research has investigated a wider range of environmental conditions.
Nevertheless, the Miller–Urey experiment provided an important proof of principle: organic molecules relevant to life can form through non-biological chemical processes.
I find this distinction essential. Demonstrating that certain ingredients can form naturally is an important scientific achievement, but it is not the same as demonstrating how all those ingredients became organized into the first living system.
If I have flour, water, yeast and other ingredients, I still need to understand the processes that transform them into bread. In the case of life, the problem is far more complex because scientists are investigating how the earliest systems acquired the capacity to maintain themselves, reproduce and evolve.
The experiment advanced our understanding, but the mystery remained.
The RNA World Hypothesis: Before DNA and Proteins?
Modern living cells depend on an elaborate relationship among DNA, RNA and proteins. DNA stores genetic information, RNA performs several important roles in information transfer and cellular function, and proteins act as enzymes, structural components and regulators.
This raises a difficult question: how did such an interdependent system first arise?
The RNA world hypothesis proposes that an earlier stage of life may have relied heavily on RNA. Unlike DNA, which principally stores genetic information, RNA can also catalyse certain chemical reactions. This dual capacity makes it an attractive candidate for a molecule that might have contributed to both information storage and chemical activity in early life.
The idea developed through the work of several researchers. Carl Woese and Francis Crick contributed important early thinking about RNA and the origin of biological information, while Walter Gilbert popularized the term RNA world in 1986.
Researchers have since investigated how RNA-like molecules might have formed, copied information and participated in chemical networks before modern cellular systems evolved.
However, several challenges remain. Scientists have not demonstrated a complete, naturally plausible pathway that explains the emergence of a self-replicating RNA system and its transition into the complex molecular machinery of modern cells.
The RNA world is therefore an influential hypothesis, not a completed account of life's origin.
Once again, I find myself asking whether identifying a plausible molecular pathway is the same as answering the ultimate question of why life exists. It may explain an important part of the mechanism, but it does not necessarily resolve every philosophical question surrounding the origin of life.
Hydrothermal Vents: Could Life Have Begun on the Ocean Floor?
Another proposal places the origin of life around hydrothermal systems on the ocean floor.
Hydrothermal vents release hot fluids rich in dissolved minerals and chemical compounds. Some systems, particularly alkaline hydrothermal vents, provide chemical gradients that may have offered energy sources and natural environments for prebiotic reactions.
Scientists including Michael J. Russell and his collaborators have explored whether mineral structures and chemical gradients in such environments could have helped concentrate molecules, promote reactions and support early forms of metabolism.
Hydrothermal systems are scientifically interesting because living organisms today can thrive in environments where chemical energy, rather than sunlight, supports ecosystems. Some modern microorganisms use metabolic pathways that provide clues about how early biochemical processes might have developed.
But the existence of life around modern hydrothermal vents does not prove that life originated there. Nor have researchers demonstrated a complete sequence from vent chemistry to the first living cell.
The proposal remains one of several serious scientific hypotheses being investigated.
Cairns-Smith and the Clay Crystal Hypothesis
The chemist A. G. Cairns-Smith proposed that mineral crystals, particularly clay structures, might have played a role in the earliest stages of life's emergence.
Certain minerals possess ordered structures, and their surfaces can influence the concentration and reactions of organic molecules. Cairns-Smith suggested that patterns associated with mineral crystals might have provided a primitive form of organization or information before biological genetic systems developed.
This proposal is sometimes described as the clay hypothesis or clay mineral theory.
It is an imaginative attempt to explain how some forms of organization might have preceded the genetic machinery of modern cells. However, mineral crystals are not living organisms, and the hypothesis has not established a complete route from mineral structures to biological reproduction and evolution.
It remains one of several approaches to understanding the transition from chemistry to life. Research into origin-of-life models continues to compare hypotheses emphasizing replication, metabolism, membranes, mineral surfaces and other processes.
I find the variety of these proposals striking. Scientists have investigated different environments and mechanisms because no single hypothesis has yet resolved every major difficulty.
The diversity of theories does not mean that scientific research is futile. It shows that the problem is complex and that competing ideas must be tested against evidence.
Panspermia: Could Life Have Arrived from Outer Space?
Another hypothesis proposes that life, or perhaps its precursors, may have arrived on Earth from elsewhere in the universe.
The idea has ancient roots, including discussions associated with the Greek philosopher Anaxagoras. In modern times, the Swedish scientist Svante Arrhenius helped popularize the concept of panspermia in the early twentieth century. Fred Hoyle and Chandra Wickramasinghe later advocated versions involving the possible distribution of biological material through space.
Panspermia proposes that microorganisms or other viable biological material might be transported by comets, meteorites, cosmic dust or other mechanisms. A more limited possibility is that organic molecules formed elsewhere and were delivered to Earth, contributing ingredients to prebiotic chemistry.
These possibilities must be distinguished. The discovery of organic compounds in meteorites supports the view that some building blocks of life can form outside Earth. It does not establish that living organisms travelled to Earth.
Likewise, the fact that rocks can be transferred between planets does not prove that viable organisms survived the entire journey and established themselves on the receiving world.
Panspermia remains unconfirmed as an explanation for the origin of life on Earth.
And here I arrive at another question that cannot be avoided.
Even if life were eventually shown to have arrived from another world, where and how did it originate there? If it came from Mars, how did life begin on Mars? If it came from a distant planet orbiting another star, how did life begin there?
Transporting life from one location to another could explain its distribution, but it would still not automatically explain its ultimate origin. Life must have come from somewhere - but where?
The question would simply have moved elsewhere.
What About LUCA, Bacteria, Archaea and the First Living Systems?
The scientific history of life extends far beyond the appearance of animals and human beings.
Bacteria and archaea represent two major groups of cellular life. Eukaryotic cells, which contain nuclei and more complex internal organization, emerged later. Multicellular organisms diversified subsequently, and animals appeared long before the human lineage.
Scientists use the term LUCA, meaning the Last Universal Common Ancestor, to describe the ancestral population from which all life alive today ultimately descends.
LUCA should not be confused with the first living organism. It represents a common ancestor of present-day life, not necessarily the earliest organism ever to exist. Earlier lineages may have existed and left no living descendants.
The fossil record, molecular biology and genetics provide evidence for the long history of life and its diversification. Stromatolites and other ancient geological structures preserve evidence of early microbial ecosystems, although the interpretation and precise dating of the oldest evidence require care.
This history creates an important question for anyone interpreting the biblical account of creation.
Genesis describes God forming the human from the dust of the ground and breathing the breath of life into him. But the scientific record indicates that microbial life existed billions of years before modern humans appeared.
How should these accounts be understood together?
Some Christians interpret Genesis as a literal chronological account. Others understand its language as theological, literary or symbolic, while accepting an ancient Earth and the evolution of life. Still others hold different positions.
I cannot assume that every religious believer interprets the text in the same way.
If I accept the scientific evidence for the long history of life, I must recognize that the origin of the first living systems and the origin of human beings are different questions. A theological interpretation of Adam does not, by itself, explain the origin of bacteria, archaea, early eukaryotes or the many organisms that lived long before human beings.
This is one reason why I want to consider whether the biblical account might address the relationship between God and human existence without necessarily providing a modern scientific chronology of every form of life.
That is an interpretive possibility, not a conclusion established by biology.
Does the Failure to Explain Everything Mean That God Must Be the Answer?
Here I must be particularly careful.
If scientists have not yet explained the origin of the first living system, it does not logically follow that God has been scientifically demonstrated as the explanation.
That would be an argument from incomplete knowledge: assuming that because one explanation remains unfinished, a particular alternative must therefore be correct.
Scientific history reminds me that many phenomena once poorly understood later acquired natural explanations. It would therefore be unwise to treat every unanswered question as proof of supernatural intervention.
But I also do not think that the inability of science to establish a divine explanation should automatically be treated as proof that God does not exist.
These are different claims.
Science generally investigates natural processes through observation, measurement, experimentation and testable explanations. A hypothesis about the formation of organic molecules, for example, can be evaluated through laboratory work and chemical analysis.
The claim that God is the ultimate source of all existence is a broader theological or metaphysical proposition. Unless it is formulated in a way that generates specific testable predictions, it is not the same kind of explanation as a chemical mechanism.
This is why scientific papers on the origin of life usually investigate molecules, energy sources, mineral surfaces and environmental conditions rather than invoking God as a scientific mechanism.
That methodological focus does not, by itself, prove that God exists or does not exist. It reflects the kind of evidence scientific research is designed to investigate.
Some scientists are religious and see no contradiction between their faith and their scientific work. Others adopt non-religious philosophical positions. Still others distinguish their personal beliefs from the conclusions they can establish through research.
I believe the most honest approach is to avoid claiming that science has proved something it has not, while also avoiding the assumption that scientific explanations necessarily settle every philosophical question about existence.
Could God Be the Ultimate Source of All Life?
This brings me to the possibility I find most meaningful in my own reflections.
I wonder whether God could be the ultimate source of all life, not merely the first human being described in Genesis, but every living organism that has existed on Earth or may exist elsewhere in the universe.
In this personal theological understanding, God would not simply be another physical object among the objects studied by science. God would be the ultimate source of existence, while the processes investigated by science would describe how the physical universe and its living systems operate.
If I hold this belief, I can imagine that natural chemical processes may have played a role in the emergence of life. I can also accept that biological evolution explains how living populations diversified over immense periods of time.
Under this interpretation, the existence of natural mechanisms would not necessarily contradict my very own strong belief in God. I might understand those mechanisms as part of the natural order through which life developed.
However, I must distinguish my interpretation from an experimentally established conclusion. Science has not demonstrated that God initiated abiogenesis, nor has it established that God did not.
The belief that God is the ultimate source of life belongs to theology and philosophy. The investigation of how the first living systems emerged belongs to origin-of-life science.
I can explore the relationship between these perspectives without pretending that one has already proved the other.
What Does the Bible Mean by the Breath of Life?
The biblical account in Genesis 2:7 describes God forming the human from the dust of the ground and breathing into his nostrils the breath of life, after which the human becomes a living being - with not just a physical body, but also with a living soul within that may be the unseen Master that controls the entire living biochemistry of the body - until the soul leaves the physical body - and all living chemistries bit-by-bit come to a grinding stop.
I find this image deeply significant as a Christian and a scientist as one, because it connects the material body with the gift of life from God.
The body is associated with the earth, while life is presented as something received rather than independently possessed.
Yet the passage does not provide a modern biochemical account of the origin of the first cell. It does not explain how bacteria, archaea or early eukaryotes emerged, nor does it set out a scientific chronology of the evolution of animals and human beings.
Yet, there remains a very strong possibility that life originated from the primordial oceans when the Spirit of God hovered over the waters when He first created Earth 4.54 billion years ago. His living spirit might have infused all kinds of life into the ancient waters - just like His breath into the nostril of Adam for him to become a living soul. See my explanation in the previous chapter here:
Did God infuse life into the ancient oceans when His Spirit hover over the the waters? here: https://scientificlogic.blogspot.com/2026/11/did-god-gave-life-into-ancient-oceans.html
Different Christian traditions interpret the relationship between body, soul, spirit and breath in different ways. Some understand the passage as describing a particular act of divine creation; others emphasize its theological meaning about humanity's dependence on God.
If I want to reconcile my belief in God with the scientific history of life, I must consider how I interpret this text rather than assume that it answers every biological question in the same terms used by modern science.
My personal belief may be that God is the ultimate source of all life. But I should state that as my theological conviction, not as a scientific conclusion derived from the Genesis passage.
This distinction allows me to respect the religious meaning of the text while taking the scientific evidence seriously.
If God Is the Source of Life, Why Did Life Develop Over Billions of Years?
This is another question worth considering.
If I believe that God is the ultimate source of life, I may wonder why the history of life appears to have unfolded through such a long sequence of changes.
The Earth formed approximately 4.5 billion years ago. Evidence of early life extends back billions of years. Microorganisms preceded complex animals by an immense period, and modern humans appeared only very recently in comparison with the age of the planet.
One possible theological interpretation is that God created a universe in which natural processes unfold over time. Under this view, the long history of stars, planets, chemical evolution and biological evolution need not be regarded as a rival to God. It may instead be understood as the unfolding history of creation.
Other religious interpretations may understand divine creation differently.
Science can investigate the age of the Earth and the evolutionary history of organisms, but it cannot infer God's intentions merely from the duration of those processes.
I therefore regard the idea that God could work through natural processes as a possible way of understanding my faith alongside scientific evidence. I do not claim that science has demonstrated that interpretation.
Is Life Merely Chemistry, or Is There Something More?
At this point, I return to the question that started my inquiry.
When I examine a living organism, I find matter, energy and extraordinarily complex biochemical systems. I can investigate cellular metabolism, genetic information, membrane function, reproduction and the many processes that sustain life.
But is the description of those processes the complete answer to the nature of life?
One scientific approach understands life through the organization and activities of living systems. Under this interpretation, life is not an additional material substance that must be inserted into a cell. It is a condition associated with a complex system capable of maintaining itself and participating in biological evolution.
Another approach to the philosophical question emphasizes that a complete account of the mechanisms may not, by itself, answer every question about the meaning or ultimate source of life.
These statements need not be treated as mutually exclusive. A person may accept the scientific explanation of biological mechanisms while also believing that life has an ultimate source or purpose beyond those mechanisms.
However, I should not confuse that belief with evidence for a separately measurable life force or soul.
No single physical substance has been identified as the universal ingredient that makes all organisms alive. Nor has a separate spiritual entity been scientifically established as the cause of biological function.
The fact that these questions remain difficult does not justify claiming that a soul has been detected. Equally, the absence of such a detection does not settle every metaphysical question about the possible existence of a spiritual reality.
I must remain honest about the limits of both my knowledge and my interpretation.
My Personal Feeling: Science Explains Much, but My Ultimate Question Remains
After considering the historical belief in spontaneous generation, the experiments of Redi, Spallanzani and Pasteur, the chemical evolution proposed by Oparin and Haldane, the Miller–Urey experiment, the RNA world, hydrothermal vents, the clay hypothesis and panspermia, I find myself with a clearer understanding of the different questions scientists are trying to answer.
I also recognize that these theories do not all have the same status. Some historical explanations have been disproved. Some modern hypotheses have substantial experimental support for individual steps but remain incomplete. Others are speculative possibilities that have not been confirmed.
The scientific investigation of life's origin continues, and I consider that a strength rather than a weakness. Scientists must be willing to revise hypotheses when evidence demands it.
Yet my philosophical question remains: even if science eventually explains the complete pathway from non-living chemistry to the first living system, will that necessarily settle the question of why the universe exists and why it permits life?
I cannot answer that conclusively.
My personal belief is that God may be the ultimate source of all life. I find this possibility meaningful because it offers a theological understanding of existence that extends beyond the mechanisms I can observe.
But I must acknowledge that this is my belief, not a conclusion that the experiments of Miller and Urey, the RNA world hypothesis or the study of hydrothermal vents have scientifically established.
At the same time, I do not believe that accepting scientific explanations automatically requires me to abandon every question about God, purpose or ultimate reality. Scientific inquiry and theological reflection address different aspects of human curiosity, even though their relationship has been debated for centuries.
I can study how life operates, investigate how it may have originated, and accept the evidence for biological evolution while continuing to reflect on whether life has an ultimate divine source.
I must also remain open to the possibility that some of my present beliefs may need reconsideration as I learn more. I am after all still a student even though retired from medical research since 1994. Intellectual humility requires me to distinguish the little I know, what I suspect and what I believe.
For me, the most honest position is neither to declare that science has already solved the mystery of life nor to claim that every unanswered question proves the existence of God.
It is to keep asking questions, examine the evidence and recognize where my own interpretation begins.
I may never personally discover the ultimate answer to the origin of life. But I can continue to explore the scientific evidence, read the historical arguments, consider theological interpretations and invite others to think about these questions with the same curiosity.
I remain open to scientific explanations of how life emerged, while personally wondering whether God may be the ultimate source of the existence that science investigates.
That is the question I wish to leave with my readers—not as a proven scientific conclusion, nor as a demand that everyone share my belief, but as an invitation to reflect on the relationship between life, nature, science and God.
Perhaps the mystery of life will continue to challenge us for generations to come. Until then, I shall remain a simple student of nature, a seeker of understanding and a person who continues to ask why there is life at all.
References for further reading
1. Redi, F. (1668). Experiments on the generation of insects, challenging the belief that maggots arise spontaneously from rotting meat.
2. Pasteur, L. (1861–1864). Experimental investigations of spontaneous generation using sterilized broth and swan-neck flasks.
3. Oparin, A. I. (English translation, 1938). The Origin of Life. Macmillan.
4. Miller, S. L. (1953). “A Production of Amino Acids Under Possible Primitive Earth Conditions.” Science, 117(3046), 528–529.
5. Gilbert, W. (1986). “The RNA World.” Nature, 319, 618.
6. Martin, W., Baross, J., Kelley, D., & Russell, M. J. (2008). “Hydrothermal Vents and the Origin of Life.” Nature Reviews Microbiology, 6, 805–814.
7. Cairns-Smith, A. G. (1982). Genetic Takeover and the Mineral Origins of Life. Cambridge University Press.
8. National Academies of Sciences. (2007). The Limits of Organic Life in Planetary Systems. National Academies Press.
9. National Academies of Sciences. (2005). Genesis: The Scientific Quest for Life's Origin. Joseph Henry Press.
