Are We Alone in a Mighty Cosmic Ocean?

 

The Cosmic Canopy: Technosignatures, the Expanding Universe, and the Resonance of Ancient Scripture

 

by:

lim ju boo @lim ju boo,

alias lin ru wu (林 如 武)  

 

Abstract

Modern astronomy has transformed humanity's understanding of the cosmos, revealing a universe of immense scale, dynamic evolution, and billions of galaxies. Within this vast environment, the Search for Extraterrestrial Intelligence (SETI) investigates whether technological civilizations may exist beyond Earth, while the study of galactic red shifts has established the expansion of the universe as a fundamental feature of modern cosmology. The historical development of this understanding involved several important contributions, including the spectroscopic observations of Vesto Melvin Slipher, the theoretical work of Alexander Friedmann and Georges Lemaître, and the distance–redshift relationship demonstrated by Edwin Hubble. Interestingly, ancient Hebrew scriptures describe the heavens using imagery of stretching and spreading, notably in Isaiah 40:22 and Psalm 104:2. These passages invite reflection on the relationship between ancient theological language and contemporary scientific understanding. This article examines the scientific foundations of cosmic expansion, the challenges of detecting extraterrestrial intelligence, and the conceptual resonance between modern cosmology and the biblical imagery of a stretched-out heaven. It argues that scientific evidence and theological interpretation can be explored in dialogue while recognizing the important distinction between empirical demonstration and poetic or religious meaning.

 

Introduction

For much of human history, the heavens appeared to be an immense but largely unchanging backdrop to terrestrial existence. The apparent daily movement of the Sun and stars, together with the slow changes of the night sky, encouraged many traditional cosmologies to regard the celestial realm as an ordered structure surrounding the Earth. Although ancient civilizations developed sophisticated astronomical systems, the true scale, composition, and dynamic history of the universe remained beyond their observational reach.

The development of modern telescopes and spectroscopy fundamentally changed this picture. Astronomers discovered that the Milky Way is only one galaxy among an enormous population of galaxies, many separated from us by distances so great that their light has travelled for billions of years before reaching Earth. Further observations revealed that the universe is expanding, meaning that the large-scale distances between gravitationally unbound galaxies generally increase with cosmic time.

These discoveries raise questions that extend beyond the mechanics of astronomy. If the universe contains so many stars and planets, could technological civilizations exist elsewhere? If they do, why have we not detected convincing evidence of their existence? And how might humanity's modern understanding of the cosmos be compared with ancient descriptions of the heavens?

Two different forms of inquiry provide the framework for this discussion. The first is empirical science, which tests hypotheses through observations, measurements, and mathematical models. The second is theological and philosophical reflection, which considers the meaning of existence and humanity's place within the universe. Although these approaches are not interchangeable, their points of contact can stimulate worthwhile intellectual exploration.

The Search for Extraterrestrial Intelligence: Listening Across the Cosmic Ocean

The Search for Extraterrestrial Intelligence, commonly known as SETI, represents humanity's systematic attempt to discover evidence of technological life beyond Earth. Radio astronomy has played an important role in this effort because radio waves can travel across interstellar distances and can be detected using appropriately designed instruments.

Researchers search for possible techno-signatures, which are observable phenomena that might indicate the presence of technology. These could include narrow-band radio emissions, unusual optical or infrared signals, or other detectable effects that cannot readily be explained by known natural processes. A candidate signal, however, must be carefully investigated to exclude terrestrial interference, instrumental artefacts, and natural astrophysical explanations.

The Drake Equation, proposed by astronomer Frank Drake in 1961, provides a framework for considering the number of communicating technological civilizations that might exist in our galaxy. Its factors include the rate of star formation, the proportion of stars with planets, the number of potentially habitable planets, the probability that life and intelligence develop, and the length of time technological civilizations remain detectable.

The equation is valuable because it separates a complex question into several component questions. Nevertheless, several of its factors remain poorly constrained. The existence of billions of stars and planets does not, by itself, establish that intelligent life must be common. The emergence of life, the evolution of complex organisms, the development of intelligence, and the appearance of detectable technology may each depend on conditions that we do not yet fully understand.

This uncertainty is closely associated with the Fermi paradox, which asks why, if technological civilizations are sufficiently common, humanity has not yet found convincing evidence of them.

Numerous explanations have been proposed. Intelligent life might be rare, technological civilizations might be short-lived, interstellar communication might be uncommon, or advanced societies might use technologies that we do not know how to detect. Civilizations may also be separated by enormous distances or may not exist at the same time.

Consequently, the absence of confirmed contact should not be interpreted as proof that extraterrestrial intelligence does not exist. It indicates that, despite considerable scientific effort, no extraterrestrial technological signal has yet been verified.

Redshift and the Discovery of the Expanding Universe

The discovery of cosmic expansion emerged from a combination of observational astronomy and theoretical physics rather than from the work of a single scientist.

An important early contribution came from Vesto Melvin Slipher at Lowell Observatory in the United States. Beginning in 1912, Slipher obtained spectroscopic observations of objects then commonly called spiral nebulae. Astronomers had not yet established that these objects were independent galaxies lying beyond the Milky Way.

By examining their spectra, Slipher measured the displacement of characteristic spectral lines from their laboratory wavelengths. Many of these objects exhibited substantial redshifts, indicating large recession velocities when interpreted using the Doppler effect. His observations provided crucial empirical evidence that the spiral nebulae possessed extraordinary motions relative to our own astronomical neighbourhood.

Meanwhile, theoretical developments were changing the way physicists understood the universe. Albert Einstein's 1917 cosmological model assumed a static universe, but his general theory of relativity also permitted other cosmological solutions. Alexander Friedmann demonstrated in 1922 that the equations could describe a universe whose scale changes with time. Georges Lemaître independently developed an expanding-universe model in 1927 and connected the theoretical possibility with astronomical observations.

Another essential development concerned the measurement of astronomical distances. Henrietta Swan Leavitt's work on Cepheid variable stars established a relationship between their pulsation periods and intrinsic luminosities. This relationship allowed astronomers to estimate distances to stars and, subsequently, to galaxies containing suitable Cepheids.

Edwin Hubble used such distance measurements, together with redshift information obtained largely by Slipher and other observers, to establish a relationship between the distances of galaxies and their apparent recession velocities. His landmark 1929 paper demonstrated that more distant galaxies generally exhibit greater recession velocities.

The relationship is now known as the Hubble–Lemaître law. In its simple nearby-universe form, it is expressed as:

v = H_0d

Here, (v) represents recession velocity, (d) represents distance, and (H_0) is the Hubble constant, which describes the present-day expansion rate.

The modern interpretation is more subtle than the statement that galaxies are simply flying away through pre-existing empty space. On sufficiently large scales, the expansion of space increases the distances between galaxies that are not gravitationally bound to one another. Light travelling through this expanding universe has its wavelength stretched, producing cosmological redshift.

It is important to recognize that redshift can arise from more than one physical mechanism. Relative motion can produce Doppler redshift, gravity can alter the wavelength of light, and cosmic expansion produces cosmological redshift. Nearby galaxies can even approach us because of local gravitational motions, despite the general expansion of the universe.

The expansion of the universe is therefore not inferred from redshift alone. It is established through the combined interpretation of redshifts, independently estimated distances, the large-scale distribution of galaxies, the cosmic microwave background, and other cosmological observations.

The resulting picture is remarkable: the universe is not a permanently fixed celestial arrangement but a physical system whose large-scale structure evolves over time.

Cosmic Expansion, Distance, and the Limits of Communication

The immense scale of the universe presents a formidable challenge to communication between possible technological civilizations.

Light travels at approximately 300,000 kilometers per second in a vacuum. This speed is extraordinarily high by terrestrial standards, yet interstellar distances are so vast that even a signal travelling at the speed of light may require years, centuries, or longer to reach another star system. Communication between galaxies may require millions or billions of years, depending on their separation and the history of cosmic expansion.

A message sent from a civilization in another star system might therefore arrive long after its original sender has disappeared. If a reply were transmitted, the response would require an additional journey. Even without considering technological limitations, the speed of light imposes a fundamental constraint on communication.

Cosmic expansion introduces further complications at the largest scales. The universe's expansion stretches light and increases the distances between sufficiently separated galaxies. Some extremely distant regions may be unable to communicate with us even in principle, because their light cannot reach us within the universe's cosmic history under the standard cosmological model.

Nevertheless, cosmic expansion should not be confused with the simple degradation of every radio signal. Electromagnetic waves can travel through intergalactic space without requiring a material medium. Their detectable strength generally diminishes with distance because the transmitted energy spreads over an increasingly large area. Additional factors, including background noise, absorption in certain environments, the transmitter's power, the receiving antenna, and the signal's frequency, influence detectability.

These distinctions matter for SETI. The universe may be vast enough to accommodate many possible civilizations, yet the probability of detecting one depends on more than the number of stars. It also depends on whether technological activity occurs, whether its signals reach us, whether we are observing the appropriate frequencies or wavelengths, and whether our instruments can distinguish the signals from natural phenomena and noise.

Humanity's apparent isolation may therefore reflect the combined effects of distance, time, limited observations, and uncertainty about the nature of extraterrestrial life. It remains an open scientific question rather than a demonstrated cosmic law.

The Biblical Image of the Stretched-Out Heavens

Long before the development of modern cosmology, ancient Hebrew writings employed vivid imagery to express the majesty and order of creation. Among the most striking examples are Isaiah 40:22 and Psalm 104:2, which describe the heavens in terms of stretching and spreading.

Isaiah 40:22 describes God as the one who sits above the circle of the Earth and stretches out the heavens like a curtain, spreading them out like a tent to dwell in. Psalm 104:2 similarly portrays God as covering himself with light and stretching out the heavens like a tent curtain.

These passages belong to a poetic and theological tradition in which the natural world is presented as an expression of divine sovereignty. The imagery of a tent is especially understandable in a culture familiar with tents and fabric coverings. Just as a tent is spread out to create a sheltered space, the heavens are depicted as being extended under the authority of the Creator.

The Hebrew verb commonly transliterated as natah can carry meanings such as stretching, extending, spreading, or inclining, depending on its grammatical form and context. In Isaiah 40:22, it contributes to the image of the heavens being stretched out. This linguistic observation supports the ordinary meaning of extension or spreading, but it does not independently establish a technical description of cosmic expansion.

The distinction is important. The ancient writer was communicating through the language, imagery, and theological understanding available within the literary world of the text. The passage does not present measurements of galaxies, a mathematical law of expansion, or an explicit account of cosmological redshift.

Nevertheless, modern readers may reasonably find the imagery evocative when considered alongside contemporary astronomy. The universe that science describes is dynamic, and the large-scale distances between galaxies change as the universe evolves. The ancient picture of heavens being stretched out thus offers a point of conceptual comparison with the modern picture of an expanding cosmos.

Whether this resemblance reflects deliberate scientific anticipation, a broader intuition about the grandeur of the heavens, or simply the enduring power of poetic imagery cannot be established from the wording alone. The resemblance is meaningful as an interpretive observation, but it should not be presented as a scientific prediction that has been conclusively verified.

Science and Scripture: Distinct Ways of Asking Questions

The relationship between scientific discovery and religious interpretation is often discussed as though the two must necessarily compete. In practice, the relationship is more nuanced.

Science investigates the physical universe through observations, experiments where possible, mathematical modelling, and the testing of explanations against evidence. Cosmology asks how the universe changes, what physical processes govern its evolution, and how its history can be reconstructed from observable phenomena.

Scripture, when read theologically, addresses questions concerning creation, divine purpose, human responsibility, and the meaning of existence. Its poetic descriptions of nature may communicate reverence, dependence, and the conviction that the universe is not independent of its Creator.

These approaches differ in their aims and methods. A theological interpretation cannot substitute for spectroscopic measurements, just as a measurement of redshift cannot, by itself, establish or disprove the existence of God.

Yet the distinction does not prevent dialogue. A person who believes that the universe is created by God may regard its laws and evolution as expressions of divine wisdom. Another person may interpret the same observations without invoking a divine explanation. Both can acknowledge the astronomical evidence while differing in their philosophical conclusions.

The idea that God created the universe is therefore a theological proposition, while the observation that the universe expands is a scientific conclusion supported by multiple independent lines of evidence. One may hold both beliefs together, but the evidential basis for each should be stated honestly.

There is also a broader lesson in the history of astronomy. Scientific knowledge has developed through the contributions of many individuals, including those whose initial interpretations were incomplete or mistaken. Slipher supplied crucial observations; Friedmann and Lemaître explored the implications of relativistic theory; Hubble connected galaxy distances with redshifts; and subsequent generations refined the evidence. The modern picture emerged gradually through the accumulation and correction of knowledge.

Such a history invites intellectual humility. Our understanding of the universe is substantial, but it remains open to refinement as new observations and better theories become available.

Conclusion: An Unfurling Cosmic Canopy

The expanding universe presents humanity with a paradox of perspective. On the one hand, modern astronomy reveals a cosmos of extraordinary scale, containing vast numbers of stars and planets. On the other hand, that same scale makes communication across interstellar and intergalactic distances profoundly difficult. The possibility of extraterrestrial intelligence remains scientifically intriguing, but its existence and prevalence have yet to be established.

The discovery of cosmic expansion was itself a remarkable achievement of human inquiry. Slipher's spectroscopic observations, Friedmann's mathematical work, Lemaître's theoretical insights, and Hubble's distance–redshift relationship helped transform the universe from an apparently static celestial background into a dynamic system with an evolving history.

Against this scientific background, the biblical descriptions of the heavens being stretched out offer a compelling subject for reflection. Isaiah 40:22 and Psalm 104:2 employ the imagery of a curtain or tent being extended to express the majesty of creation. Their language is not a scientific formulation of the expansion of space, but its imagery harmonizes with the modern understanding of a universe whose large-scale structure changes with time.

For the believer, this resonance may deepen a sense of wonder at the cosmos and its Creator. For the scientist, it may illustrate how ancient cultures expressed their understanding of the heavens through powerful metaphors. For the thoughtful reader, it provides an opportunity to consider how different intellectual traditions approach the same vast reality from different perspectives.

Perhaps the most important lesson is not that ancient poetry and modern cosmology say precisely the same thing, but that humanity continues to search for meaning beneath the canopy of the heavens. Science asks how the universe behaves and evolves; philosophy and theology ask what its existence may mean. Neither question should be confused with the other, yet both arise from humanity's enduring desire to understand its place in the cosmos.

As our telescopes continue to explore the depths of space and our instruments listen for possible signals from distant worlds, the universe remains both an object of scientific investigation and a source of profound reflection. The cosmic canopy continues to unfold in our understanding, reminding us of the extraordinary scale of creation and the limits of our present knowledge.

Three Guiding Principles for Reflection

Before drawing conclusions about the relationship between modern cosmology and ancient Scripture, readers may wish to consider three important principles.

First, we should not weaken scientific evidence in an attempt to strengthen a theological argument. The expansion of the universe is supported by astronomical observations and physical theories. Its validity does not depend on whether an ancient scriptural passage appears to anticipate it.

Second, the absence of scientific proof does not necessarily deprive a theological interpretation of its philosophical or spiritual significance. Ancient descriptions of the heavens may inspire reflection on creation and the Creator, even when their original literary meanings differ from modern scientific explanations.

Third, the search for extraterrestrial intelligence must be distinguished from proof of extraterrestrial life. SETI is a legitimate scientific endeavour, but the existence, prevalence, and technological capabilities of extraterrestrial civilizations remain unresolved questions.

Together, these principles encourage us to approach both science and Scripture with intellectual honesty, humility, and an openness to deeper understanding. We need not confuse scientific evidence with religious belief, nor assume that meaningful dialogue between them is impossible.

References

1. Ball, J. A. (1973). The zoo hypothesis. Icarus, 19(3), 347–349.

2. Drake, F., & Sobel, D. (1992). Is Anyone Out There? The Scientific Search for Extraterrestrial Intelligence. Delacorte Press.

3. Einstein, A. (1917). Kosmologische Betrachtungen zur allgemeinen Relativitätstheorie. Sitzungsberichte der Königlich Preussischen Akademie der Wissenschaften, 142–152.

4. Friedmann, A. (1922). Über die Krümmung des Raumes. Zeitschrift für Physik, 10, 377–386.

5. Hubble, E. (1929). A relation between distance and radial velocity among extra-galactic nebulae. Proceedings of the National Academy of Sciences, 15(3), 168–173.

6. Hubble, E., & Humason, M. L. (1931). The velocity–distance relation among extra-galactic nebulae. The Astrophysical Journal, 74, 43–80.

7. Lemaître, G. (1927). Un univers homogène de masse constante et de rayon croissant rendant compte de la vitesse radiale des nébuleuses extragalactiques. Annales de la Société Scientifique de Bruxelles, 47, 49–59.

8. Leavitt, H. S., & Pickering, E. C. (1912). Periods of 25 variable stars in the Small Magellanic Cloud. Harvard College Observatory Circular, 173, 1–3.

9. NASA. (n.d.). Cosmological Redshift. NASA Science.

10. The Holy Bible. Isaiah 40:22; Psalm 104:2; Genesis 1:1.

11. Sagan, C. (1994). Pale Blue Dot: A Vision of the Human Future in Space. Random House.

12. Slipher, V. M. (1915). Spectrographic observations of nebulae. Popular Astronomy, 23, 21–24.

13. Webb, S. (2015). If the Universe Is Teeming with Aliens... WHERE IS EVERYBODY? Seventy-Five Solutions to the Fermi Paradox and the Problem of Extraterrestrial Life (2nd ed.). Springer.

From Hunter-Gatherers to Modern Humans

 

FROM HUNTER-GATHERERS TO MODERN HUMANS: HAVE WE GAINED A LONGER LIFE OR A MORE COMPLICATED ONE?

Human longevity, mortality, healthcare, social demands, and the price of civilization

Introduction: The Paradox of Human Progress

 

by  lim ju boo, alias lin ru wu (林 如 武)

When we examine the history of humanity, we are confronted by a remarkable paradox. Our ancestors lived much closer to nature, obtaining food from wild plants and animals, finding shelter in caves or simple dwellings, and depending directly upon the natural environment for survival. They possessed few material goods and had little of the technology that we now consider indispensable.

Today, modern humans inhabit a very different world. We live in houses and apartments, travel in motorcars and aeroplanes, communicate through smartphones, and depend upon sophisticated systems of agriculture, industry, transport, electricity, and healthcare. We have developed vaccines, antibiotics, surgical techniques, diagnostic instruments, and treatments for diseases that once caused widespread premature death.

These achievements have transformed human existence. In many countries, people can now expect to live considerably longer than their ancestors did a few centuries ago.

Yet a question remains: Has our progress made us healthier and happier, or have we exchanged the difficulties of primitive survival for a different collection of physical, psychological, social, and economic burdens?

We must be careful not to romanticize the past. Our ancestors faced hunger, injuries, infections, childbirth complications, and many dangers for which they had little effective protection. Nor should we dismiss the extraordinary benefits of modern science and medicine.

Nevertheless, it is worth asking whether our increasingly complicated way of life has introduced new problems that undermine some of the advantages we have gained.

Perhaps the most important distinction is between living longer and living better. They are related, but they are not identical.

The World of Our Hunter-Gatherer Ancestors

For most of human evolutionary history, our ancestors lived as hunter-gatherers. They obtained food by gathering edible plants, fruits, seeds, roots, nuts, and other naturally available resources, supplemented by hunting and fishing where circumstances permitted.

They did not depend upon modern supermarkets, industrial agriculture, processed foods, or global supply chains. Their survival required detailed knowledge of their surroundings, including seasonal changes, animal behaviour, edible plants, water sources, and the availability of shelter.

Daily physical activity was an unavoidable part of life. Depending on the environment and their way of life, people walked considerable distances, carried food, gathered fuel, prepared shelter, and performed other tasks necessary for survival.

Their diets varied greatly according to geography, season, and local ecology. Some communities consumed substantial amounts of animal foods, while others depended more heavily on plant foods. It would therefore be inaccurate to imagine that all prehistoric humans ate the same diet or enjoyed uniformly abundant natural food.

Their social lives were also different from ours. Many hunter-gatherer societies lived in relatively small communities, sharing practical knowledge and depending upon cooperation for survival. Their economic systems did not resemble modern economies built around wages, mortgages, commercial advertising, financial markets, and the continual purchase of manufactured goods.

However, life was not necessarily peaceful or stress-free. Food shortages, injuries, infections, conflicts, and environmental changes could threaten survival. Without effective antibiotics, modern surgery, or advanced obstetric care, an illness or injury that is manageable today could prove fatal.

The absence of industrial pollution and many modern consumer pressures may have offered certain advantages, but it did not protect our ancestors from the hazards of the natural world.

We should therefore regard hunter-gatherer life neither as an ideal paradise nor as a miserable existence. It was a different form of human adaptation, with its own advantages, limitations, and risks.

Did Ancient Humans Live Longer Than We Do Today?

This is one of the most important questions in our discussion.

It is tempting to suppose that because our ancestors lived closer to nature, ate less processed food, and engaged in more physical activity, they must have enjoyed longer lives. But the available demographic and archaeological evidence does not support the conclusion that prehistoric hunter-gatherers generally lived longer than modern humans.

The principal difficulty is understanding what scientists mean by life expectancy.

Life expectancy at birth is a statistical estimate based on the mortality rates experienced by people of different ages. If a population has high infant and childhood mortality, its life expectancy at birth can be very low, even when some individuals survive into their sixties or seventies.

Consider a hypothetical population in which many children die before reaching five years of age, while others survive to 65, 75, or beyond. Its average life expectancy at birth would be much lower than that of a population in which most children survive and adults have better chances of reaching old age.

This distinction is essential when comparing prehistoric populations with modern ones.

Historical records and demographic reconstructions show that life expectancy has increased dramatically over the past two centuries. Our World in Data reports that global life expectancy at birth was approximately 32 years in 1900, compared with about 71 years in 2021. The improvement resulted from reductions in mortality across several age groups, particularly among infants and children. [1]

These figures do not mean that every person in 1900 died at 32, nor that people today will necessarily die at the age represented by their country's current life expectancy.

They describe population-level mortality patterns, not the maximum biological lifespan of an individual.

Archaeological evidence can sometimes identify people who survived into older adulthood, but estimating the ages of ancient remains is difficult, and the surviving skeletons do not provide a complete census of the population. Consequently, claims that prehistoric people routinely lived longer than modern humans must be treated with caution.

A natural environment and a physically active lifestyle may have offered certain health advantages. Nevertheless, the absence of modern sanitation, effective infection control, emergency surgery, and reliable food supplies created substantial risks that could shorten life.

Adam, Methuselah, and the Biblical Perspective on Longevity

The question of human longevity also brings us to the biblical accounts of Adam and Methuselah.

According to Genesis 5, Adam lived for 930 years, while Methuselah lived for 969 years. These are the ages reported in the biblical narrative, and they have long attracted the attention of readers interested in the origins and duration of human life.

For believers, these accounts may carry theological significance concerning humanity's relationship with God, the history of creation, and the nature of life and death.

From the standpoint of modern science, however, we do not possess independent demographic evidence confirming that prehistoric human beings routinely lived for hundreds of years. The biblical ages cannot be treated as scientifically verified measurements of prehistoric longevity.

It is useful to distinguish the spiritual interpretation of a religious text from the methods used to establish biological and demographic facts. Respecting the significance of a biblical account does not require us to claim that science has independently verified every detail of it.

At the same time, the broader question raised by these accounts remains intellectually interesting: What determines how long a human being can live, and what conditions allow a person to approach the limits of human longevity?

Modern biology investigates this question through genetics, cellular processes, organ function, disease patterns, and the effects of nutrition and the environment. Although scientists have made considerable progress in understanding ageing, the mechanisms that determine the ultimate limits of human life remain incompletely understood.

The Great Transformation: From High Mortality to Longer Life

The most important transformation in human longevity did not arise from one medical discovery alone. It resulted from numerous improvements that gradually changed the conditions under which people were born, grew up, worked, and aged.

In earlier centuries, infectious diseases, contaminated drinking water, poor sanitation, malnutrition, and unsafe childbirth contributed heavily to premature mortality. Epidemics could devastate communities, while a lack of effective treatment made many otherwise manageable illnesses dangerous.

The development of public sanitation, safer water supplies, improved housing, better nutrition, vaccination, antibiotics, and modern obstetric care changed this situation profoundly.

Vaccines prevented many infectious diseases. Antibiotics made it possible to treat numerous bacterial infections that were once frequently fatal. Improved surgical techniques and anaesthesia expanded the range of conditions that could be treated. Blood transfusion, intensive care, diagnostic imaging, and laboratory investigations further increased the ability of healthcare professionals to recognize and manage serious illness.

These developments did not occur in isolation. Better agricultural productivity, improved transport, education, and economic development also helped people obtain food, maintain cleaner living environments, and access medical services.

The result was a major decline in premature mortality.

The World Health Organization estimates that global life expectancy at birth reached 73.3 years in 2023, approaching the pre-pandemic figure of 73.4 years recorded in 2019. This is a population average, and substantial differences remain between countries and communities. [2]

Modern civilization has therefore achieved something extraordinary: more people survive childhood, more adults reach old age, and many illnesses that once caused early death can now be prevented or treated.

We should not underestimate these accomplishments. Without them, the lives of many people living today would have been considerably shorter.

Mortality Rates: Why People Died Earlier in the Past

To understand the improvement in longevity, we must examine the causes of death.

In populations with high mortality, infectious diseases and nutritional deficiencies can claim lives at almost any age. Infants may die from infections, premature birth, or complications that modern medicine can often manage more effectively. Children may succumb to diarrhoeal diseases, pneumonia, or other infections. Adults may die from injuries, childbirth complications, or diseases for which effective treatments are unavailable.

Modern sanitation, vaccination, improved nutrition, and access to healthcare have substantially reduced many of these risks.

However, the pattern of mortality changes as populations become healthier and older. When fewer people die prematurely from infectious diseases, a larger proportion of the population survives long enough to develop age-related conditions such as cardiovascular disease, cancer, dementia, and other chronic disorders.

This does not mean that modern medicine has created these diseases simply by enabling people to live longer. Rather, survival into older age allows more time for chronic diseases and age-related biological changes to develop.

Modern populations consequently face a different balance of health challenges from those experienced by many earlier societies.

The objective of healthcare is not merely to postpone death from one disease until another appears. It is also to prevent illness, preserve functional ability, relieve suffering, and help people remain independent for as long as possible.

Life Expectancy Is Not the Same as Maximum Lifespan

Another important distinction is between life expectancy and maximum lifespan.

Life expectancy describes the average number of years a population can expect to live under specified mortality conditions. Maximum lifespan concerns the upper end of the ages reached by individual human beings.

A country can increase its life expectancy by reducing deaths among infants, children, young adults, and middle-aged people without necessarily changing the maximum age that any human being can attain.

Likewise, improvements in the survival of older adults can increase life expectancy even when the gains are smaller than those achieved through earlier reductions in childhood mortality.

Human ageing involves numerous biological processes, including changes in cellular function, the accumulation of molecular damage, alterations in immune function, and the gradual loss of resilience in tissues and organs. These processes interact in complicated ways.

Scientists are investigating whether future treatments can delay particular aspects of ageing, prevent age-related disease, or extend healthy life. But it would be premature to assume that human beings will soon live for 150, 200, or 1,000 years simply because biotechnology continues to advance.

The scientifically defensible objective is to extend healthy life while reducing preventable disease and disability. Whether maximum human lifespan can be substantially increased remains an open question.

Have We Become Healthier, or Merely Better at Treating Disease?

Modern medicine has greatly improved the ability to prevent and treat illness. Nevertheless, the existence of advanced medical technology does not automatically mean that every aspect of modern life promotes health.

Many contemporary societies face substantial burdens from cardiovascular disease, diabetes, obesity, certain cancers, and other chronic conditions. Their causes vary, and it would be simplistic to attribute them all to modern lifestyles. Ageing populations, genetics, socioeconomic circumstances, environmental exposures, and access to preventive care also influence these diseases.

Still, certain modifiable factors deserve attention.

Physical inactivity can contribute to poor metabolic health. Diets that are excessively energy-dense and nutritionally unbalanced can increase the risk of obesity and related diseases. Smoking, excessive alcohol consumption, inadequate sleep, and persistent stress can further undermine health.

Conversely, regular physical activity, a balanced diet, sufficient sleep, avoidance of tobacco, and effective management of established risk factors can help preserve health.

The lesson is not that ancient life was necessarily healthier, but that modern societies sometimes neglect basic biological requirements while investing heavily in treating the consequences.

A sophisticated hospital is essential when a person becomes seriously ill. Yet preventing disease through good living conditions, healthy behaviours, vaccination, and timely medical care can be equally important.

The best approach combines prevention with effective treatment rather than treating them as competing alternatives.

The Hidden Cost of Modern Social and Economic Life

Our ancestors faced immediate challenges associated with survival. Modern people face these challenges too, but many also experience pressures arising from complex economic and social systems.

Housing costs, mortgages, employment insecurity, financial commitments, educational competition, caregiving responsibilities, and the expectation of maintaining a particular standard of living can produce persistent stress.

Technology has made communication faster, but it has also made many people continually reachable. Work messages may arrive outside normal working hours, while social media can encourage constant comparison with the achievements, possessions, and lifestyles of others.

The result may be a sense that one must continually work harder, earn more, acquire more, and accomplish more simply to avoid falling behind.

Not everyone experiences these pressures in the same way. Modern employment can provide purpose, companionship, financial independence, and personal fulfilment. Economic development can improve health by providing better housing, food security, education, and healthcare.

The problem arises when the demands of work and consumption become excessive relative to a person's physical and psychological resources.

The World Health Organization and International Labour Organization reported that working at least 55 hours per week was associated with an increased risk of ischaemic heart disease and stroke compared with working 35–40 hours per week. Their analysis estimated that long working hours were attributable to approximately 745,000 deaths from these two conditions worldwide in 2016. [3]

These findings do not prove that every form of work-related stress causes disease, nor that all modern workers are exposed to dangerous conditions. They do, however, demonstrate that economic activity can carry measurable health costs when working hours become excessive.

A society that increases production while damaging the health of its workforce must ask whether it is achieving genuine progress.

Economic activity should support human well-being, not consume so much of people's time and energy that they have little opportunity to enjoy the lives they are working to sustain.

The Biological Needs of Life Versus the Material Desires of Humanity

This brings us to one of the central observations behind our discussion.

Every living organism requires suitable conditions for survival. Animals need food, water, energy, and a habitat appropriate to their biology. Plants require light, water, nutrients, and suitable environmental conditions. Microorganisms also depend upon particular combinations of nutrients and physical conditions.

Human beings share these fundamental biological requirements.

Yet human civilization has developed an enormous range of activities and desires that extend far beyond immediate biological necessity. We manufacture luxury goods, replace functional products with newer models, build increasingly elaborate structures, and consume resources for entertainment, prestige, convenience, and competition.

There is nothing inherently wrong with enjoying art, music, comfortable housing, technology, or other products of human creativity. Such activities can enrich life and provide genuine benefits.

The difficulty arises when the pursuit of material goods becomes excessive, wasteful, or environmentally destructive.

A person does not need the latest smartphone to maintain cellular health. A family does not require an unnecessarily large house to obtain adequate shelter. Society does not benefit when usable goods are discarded merely because they are no longer fashionable.

The distinction is between material activities that genuinely support human welfare and those whose benefits are too small to justify their environmental and social costs.

Moreover, human needs are not purely biological. We also need affection, companionship, intellectual stimulation, cultural expression, and a sense of belonging. These are important aspects of human well-being, even though they cannot be reduced to food, water, and shelter alone.

A mature civilization would therefore seek to meet both our biological and social needs while reducing unnecessary material consumption.

The Environment: When Modern Comforts Undermine Future Health

Modern civilization depends upon vast quantities of energy, water, minerals, land, and manufactured materials. These resources support hospitals, transport systems, agriculture, housing, communications, and industry.

But extracting and processing resources can generate pollution, destroy habitats, and contribute to climate change. Industrial and agricultural waste can contaminate ecosystems, while excessive consumption increases the demand for new materials and energy.

Environmental deterioration can eventually return to affect human health through contaminated air and water, heat exposure, food insecurity, infectious disease risks, and damage to essential infrastructure.

This creates a paradox. The same civilization that has developed sophisticated medical treatments may undermine some of the environmental conditions necessary for good health.

It is not necessary to reject modern technology to address this problem. Cleaner energy, more efficient transport, sustainable agriculture, pollution control, resource recovery, and better urban planning can reduce many environmental harms.

The goal should be to preserve the genuine benefits of civilization without assuming that every increase in production or consumption represents progress.

Human health cannot be separated entirely from the health of the ecosystems upon which food production, water supplies, and stable living conditions depend.

Can We Live Longer by Living More Simply?

A simpler life cannot guarantee longevity, and there is no sound basis for claiming that returning to a prehistoric lifestyle would make modern humans live longer. Nevertheless, certain elements of a less stressful and less consumption-driven life could improve health.

Regular movement, nutritious food, sufficient rest, meaningful relationships, time outdoors, and a reasonable balance between work and leisure are compatible with modern scientific understanding of health.

Reducing unnecessary financial commitments and resisting excessive consumer pressure may also improve quality of life for some people. However, individual circumstances differ, and stress cannot always be eliminated through personal choices alone. Employment conditions, housing affordability, caregiving demands, and access to social support may require wider institutional solutions.

A healthier society would not ask every individual to solve structural problems through willpower. It would also create environments in which healthy choices are practical and affordable.

For example, cities could provide safe walking paths and accessible public transport. Employers could respect reasonable working hours. Schools could teach nutrition and physical activity. Governments could protect clean water, control pollution, and support effective preventive healthcare.

Such changes would not take us backwards. They would use the achievements of modern civilization to create conditions more compatible with human biology.

Perhaps the objective should be to retain the knowledge and benefits of civilization while discarding its unnecessary burdens.

The Meaning of a Longer Life

Even if future medical discoveries enable more people to live beyond 90 or 100 years, we must still ask what those additional years will be like.

A longer life spent in good health, with independence, meaningful relationships, and opportunities for learning, can be a wonderful achievement. A longer life dominated by severe illness, pain, disability, or social isolation presents a different challenge.

This is why healthy life expectancy is an important complement to ordinary life expectancy.

According to the World Health Organization, global healthy life expectancy at birth was estimated at 62.8 years in 2023, compared with overall life expectancy of 73.3 years. These measures describe different aspects of population health; they do not mean that every person becomes unhealthy at 62.8 years. [2]

The difference reminds us that living longer and living in full health are not the same thing.

Medicine should continue to seek better treatments, prevent disease, and relieve suffering. At the same time, societies should consider how to improve the quality of the years people live, rather than concentrating exclusively on extending their number.

Human life has value beyond its economic productivity. Older people should not be regarded merely as retired workers, and younger people should not be valued only for their future earning capacity.

A humane civilization recognizes the dignity of people at every stage of life.

Progress Should Serve Life, Not the Other Way Around

From our hunter-gatherer ancestors to modern civilization, humanity has undergone an extraordinary transformation. We have developed agriculture, cities, industry, science, and medicine. We have reduced many causes of premature death and enabled far more people to reach old age.

These achievements should be celebrated rather than dismissed.

Yet the story is incomplete if we measure progress only through technological sophistication, economic output, or the number of years people live.

Our ancestors faced the harsh realities of natural survival. Modern humans have gained protection from many of those dangers, but we have also created new pressures through complex economies, excessive consumption, environmental degradation, and the constant pursuit of material advancement.

The answer is not to return to caves or abandon scientific medicine. It is to recognize that the benefits of civilization should support the needs of life rather than create an endless cycle of production, consumption, and dissatisfaction.

We need food, water, shelter, healthcare, education, companionship, and opportunities to live meaningfully. We can enjoy art, music, science, technology, and other expressions of human creativity without treating unlimited material accumulation as the purpose of existence.

Perhaps the true measure of progress is not how many possessions we acquire, how much wealth we accumulate, or even how many years we add to our lives. It is how successfully we preserve health, dignity, relationships, and the natural environment while reducing avoidable suffering.

The future of longevity will depend partly upon scientific discoveries, but also upon the social and environmental conditions in which people live. Medical science may help us survive diseases that once killed us prematurely, yet a healthy society must also protect the conditions that allow people to flourish.

Our ancestors lived in a world that imposed limits upon their material ambitions. Modern humanity possesses the power to overcome many natural limitations, but that power does not exempt us from biological realities or ecological constraints.

Perhaps the next stage of civilization requires a different kind of wisdom: the ability to distinguish what we can acquire from what we truly need, what we can produce from what we ought to produce, and what makes life longer from what makes life worth living.

We cannot turn back the clock of civilization, but we can learn to live more wisely within it. The greatest achievement may not be to prolong life indefinitely, but to make the years we have healthier, more meaningful, and more harmonious with the living world that sustains us.

References

 

1. Dattani, S., Rodés-Guirao, L., Ritchie, H., Ortiz-Ospina, E., & Roser, M. Life Expectancy. Our World in Data. Historical trends and explanations of changes in global life expectancy. https://ourworldindata.org/life-expectancy

2. World Health Organization. Life Expectancy and Healthy Life Expectancy. Global Health Observatory. Global estimates and definitions of life expectancy and healthy life expectancy. https://www.who.int/data/gho/data/themes/mortality-and-global-health-estimates/ghe-life-expectancy-and-healthy-life-expectancy

3. Pega, F., Náfrádi, B., Momen, N. C., et al. (2021). Global, regional, and national burdens of ischemic heart disease and stroke attributable to exposure to long working hours for 194 countries, 2000–2016: A systematic analysis from the WHO/ILO Joint Estimates of the Work-related Burden of Disease and Injury. Environment International, 154, 106595. https://doi.org/10.1016/j.envint.2021.106595

4. World Health Organization. Global Health Estimates. Mortality, life expectancy, and disease burden data by country, age, sex, and cause. https://www.who.int/data/global-health-estimates

5. World Health Organization & International Labour Organization. (2021). Long working hours can increase deaths from heart disease and stroke. https://www.who.int/news/item/17-05-2021-long-working-hours-increasing-deaths-from-heart-disease-and-stroke-who-ilo