A humane urbanism would understand illumination as a matter of proportion rather than maximization. It would recognize that visibility is not the highest urban value and that excessive exposure can damage both ecological and human life.
For most of human history, darkness was not an exception in urban life. It was part of the ordinary condition of inhabiting the world.
Nighttime framed resting, shaped social rhythms, protected ecosystems, and connected human beings to realities larger than themselves. Today, however, many cities behave as if darkness were a defect to be eliminated rather than a dimension of life to be preserved.
Artificial illumination has undoubtedly transformed urban civilization in extraordinary ways. It has expanded mobility, enabled nighttime activity, and increased visibility in public space. Yet the contemporary tendency to equate brightness with progress has obscured something essential: darkness is not the opposite of civilization. It is one of the conditions that make civilization human.
The problem is not light itself, but excess. Across much of the world, urban environments are becoming permanently illuminated, saturated by commercial lighting, infrastructure systems, screens, advertisements, and architectural spectacles. The night is increasingly treated as unfinished daytime — a temporal gap to be dominated by uninterrupted activity and visibility.
But human beings were not made for permanent exposure.
Darkness as a biological necessity
The human body depends on cycles of light and darkness. Sleep, hormonal regulation, attention, metabolism, and psychological recovery are deeply connected to circadian rhythms shaped over thousands of years. Artificial light at night interferes directly with these rhythms, weakening the distinction between activity and rest.
A city that remains perpetually luminous does not merely extend the day. It reorganizes human life around conditions for which the body was never designed.
The consequences are increasingly visible. Sleep disorders, fatigue, anxiety, cognitive overload, and chronic exhaustion have become common features of contemporary urban existence. Although many factors contribute to these conditions, the disappearance of darkness forms part of a broader environment in which human beings are expected to remain continuously active, reachable, stimulated, and productive.
The modern city often celebrates this condition as efficiency. Yet efficiency without limits eventually becomes a form of violence against human rhythm.
The ecological life of the night
Darkness is also an essential part of the ecological system.
Artificial light affects migration patterns, feeding cycles, reproduction, orientation, and habitat behavior across countless species. Insects, birds, turtles, plants, and aquatic ecosystems are all influenced by the expansion of urban illumination. The night is not empty space waiting to be filled by technology; it is a living environmental condition with its own biological order.
When cities flood the night with excessive brightness, they alter ecosystems in ways that are often invisible to urban populations themselves. Artificial illumination does not simply affect individual species; it redistributes them across the urban landscape. High-intensity and blue-rich lighting can repel birds, insects, and other nocturnal animals from illuminated districts while concentrating them in the remaining pockets of darkness, such as peripheral forests, urban parks, and undeveloped areas. As darkness becomes fragmented, ecological relationships are displaced and compressed into increasingly limited spaces. Pollinators disappear from some areas, migratory routes are altered, and the balance between predators and prey is disrupted.
These changes reverberate through ecological processes that ultimately support human life, including pollination, pest control, and biodiversity. Yet urban populations often perceive only the immediate benefits of brightness while the gradual reorganization of the nocturnal environment remains largely unseen. Artificial light does not eliminate darkness uniformly; it pushes it to the margins. In doing so, it also pushes the ecological life that depends upon darkness to the margins of the city itself.
This is why the question of darkness cannot be reduced to aesthetics or energy efficiency alone. It is fundamentally tied to how civilization understands its relationship with the natural world.
A society that cannot tolerate darkness may ultimately struggle to coexist with anything it cannot fully control.
More light does not necessarily mean better cities
One of the dominant assumptions of contemporary urbanism is that brighter cities are more developed cities. Illumination becomes associated with prosperity, dynamism, modernization, and security. This assumption deserves far greater scrutiny.
Some of the most thoughtful urban lighting strategies today are based not on maximizing brightness, but on carefully limiting and directing it. A well-designed city is not the one that eliminates night altogether. It is the one that understands where light is necessary, where it is excessive, and where darkness should remain intact.
This distinction matters because urban quality cannot be measured solely through visibility. Public life depends not only on illumination, but on atmosphere, legibility, comfort, orientation, and emotional experience. Excessive lighting often produces spaces that feel sterile, overstimulating, and psychologically exhausting rather than welcoming.
In many cases, less illumination can create environments that feel calmer, safer, and more human precisely because they preserve contrast, depth, and rhythm. By reducing glare and limiting blue-rich light at night, such settings may support circadian regulation, improve sleep quality, and reduce some of the physiological stress associated with excessive nocturnal exposure. The Artificial Light at Night: State of the Science 2024 report, published by DarkSky International, associates exposure to artificial light at night, particularly blue-rich light, with melatonin suppression and circadian disruption, identifying possible links to insomnia, depression, obesity, diabetes, neurodegenerative diseases, and certain cancers, especially among older adults.
Because melatonin plays an essential role in sleep regulation and immune function, preserving darker nighttime environments may contribute not only to ecological health but also to human well-being. They also help preserve the visibility of the night sky, reinforcing a sense of orientation within a larger natural world. For billions of years, the dim illumination of the moon and stars dominated the nocturnal landscape, and the complete disappearance of darkness from urban life represents a remarkably recent condition in human history.
Therefore, a mature urban culture understands that good lighting is not about conquering darkness. It is about learning how to coexist with it intelligently.
Darkness and imagination
The deepest reason human beings need darkness may not be biological or ecological, but existential.
Contemporary urban life is increasingly dominated by total visibility. Screens illuminate homes, offices, streets, vehicles, and even moments once associated with silence or solitude. Every surface becomes exposed, monitored, and continuously available for stimulation. In such conditions, imagination itself begins to weaken.
Darkness matters because it preserves partiality. It allows the world to remain incomplete.
Human life does not unfold entirely under conditions of total visibility. Some of its deepest experiences depend precisely on what remains partially hidden, ambiguous, or unresolved. Romance, desire, contemplation, faith, memory, and even friendship often emerge not through complete exposure but through gradual revelation.
The erotic dimension of life, in its broadest and most human sense, depends upon distance, anticipation, mystery, and the awareness that not everything can be immediately consumed or illuminated. A civilization that abolishes darkness risks weakening precisely those experiences that give emotional and symbolic depth to human existence.
Excessive illumination does not merely brighten cities. It can flatten experience itself.
Human beings do not experience cities merely as functional systems. They inhabit them emotionally, sensorially, and symbolically. Memory, atmosphere, anticipation, ambiguity, and introspection all shape how urban environments are perceived. A city composed entirely of uniform exposure gradually loses the capacity to evoke these experiences.
Shadows, dimness, and silence are not absences of urban life. They are part of its texture.
The architecture theorist Juhani Pallasmaa has long argued that modern environments often impoverish sensory experience by privileging visual domination and constant stimulation over embodied perception. As he writes in his book The Eyes of the Skin, “the current industrial mass production of visual imagery tends to alienate vision from emotional involvement and identification, and to turn imagery into a mesmerising flow without focus or participation”. Similarly, the disappearance of darkness through the constant spectacle of lights intensifies this problem. A world without shadows becomes a world without depth, since imagination requires spaces that are not fully predetermined.
Darkness allows pause, inwardness, and contemplation. It creates conditions in which memory and attention can deepen rather than scatter endlessly across illuminated surfaces.
The disappearance of night
Modern cities increasingly aspire to permanent activity. Commercial districts operate continuously, digital infrastructures remain active without interruption, and urban economies reward constant circulation and availability. The ideal metropolis becomes a place that never sleeps.
Yet the disappearance of night carries cultural consequences far beyond infrastructure.
A civilization without darkness gradually loses its sense of limit. If every hour becomes equivalent, then time itself flattens into uninterrupted productivity. Rest appears unproductive. Silence appears empty. Stillness becomes suspicious.
But human beings cannot live meaningfully without intervals of withdrawal.
Night historically provided precisely this interruption. It distinguished labor from rest, public intensity from domestic quiet, visibility from introspection. The loss of darkness, therefore, represents not only an environmental transformation but a transformation in how societies experience time itself.
The result is often a paradoxical condition: cities become more illuminated while people become more psychologically exhausted.
Toward a more humane urban lighting
The solution is not to reject technology or romanticize premodern life. Artificial illumination remains indispensable to urban civilization. The question is not whether cities should use light, but how.
A humane urbanism would understand illumination as a matter of proportion rather than maximization. It would recognize that visibility is not the highest urban value and that excessive exposure can damage both ecological and human life. It would treat darkness not as a failure of infrastructure, but as part of the environmental and psychological balance necessary for civilization itself.
Such an approach requires intellectual humility. It requires recognizing that not every dimension of human well-being can be optimized through technical systems alone.
Cities are not simply machines for circulation and productivity. They are environments in which human beings seek meaning, belonging, memory, rest, and orientation within the world.
To preserve these possibilities, cities will need more than light.
They will need darkness too.
Felipe Camolesi Modesto
Sorocaba
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