The enlightening double

Light compels scientists to embrace its dual nature, inspires artists to use it to create emotion, and teaches us all the value of coexistence

Since humanity first raised its eyes to the stars, it has pondered the nature of light. Some found answers in poetry, religion, literature, and various forms of art, while others persisted in wanting to understand the nature of this phenomenon from a scientific point of view as well. Our civilisation spent years studying and classifying light, only to realise it could not do so definitively, as light has a dual nature: it is both wave and particle.

Naturally and inevitably dual

«Like a two-sided coin, light exhibits all the characteristics of a wave—such as frequency, colour, and wavelength—yet it is also matter, formed by light quanta called photons, which, like electrons and protons, belong to the vast family of elementary particles physicists use to describe matter and the forces acting within the universe».  This is how Italian astrophysicist Giulia Fabriani explains the coexistence of light’s two distinct natures. She recently dedicated an entire book to the topic: Storia della luce (Il Saggiatore), meaning “History of light”.

For a scientist like Fabriani, light’s dual nature offers many advantages: «It allows us to study light by exploiting both its wave characteristics—similar to sound waves—and those of particles. Depending on its behaviour, we can choose the most suitable approach. Incredibly, all of this has been rigorously proven by scientific theories and experiments».

Two theories, many experiments, one (dual) truth

Scientists, especially those involved in physics, always like to find a reason and classify phenomena as unambiguously as possible. It was therefore not at all easy to accept that they could not do this with a phenomenon as difficult to hide as light. Wave or particle?

For several centuries, scientific discoveries supporting one theory or the other went round and round. «It happens a lot in scientific research. Even with the Big Bang theory, before observational proof emerged, the scientific community was divided in two», Fabriani recalls. «Some believed the universe to be eternal and unchanging, while others argued for an initial moment from which everything began. In that case, cosmological observations ultimately favoured the Big Bang supporters. But with light, things took a different turn: it was one of the very few cases in which nature proved both teams right, leading to a final agreement between two theories». Before accepting light’s dual nature, both “teams” conducted numerous experiments, revealing many new insights into this phenomenon.

Isaac Newton, one of the fathers of the scientific method, supported the particle theory: if we point beams of light through a prism, we observe them splitting into the full spectrum of rainbow colours, suggesting that light is a stream of particles. «His hypothesis explains physical phenomena such as the reflection and refraction of light, but it leaves other issues unresolved», Fabriani explains. «One is the slit experiment: when a beam of light passes through a slit, it creates a pattern of light and shadow that seems unexpected at first glance. Why? This can only be explained by assuming that light is a wave».

Indeed, at the end of the 19th century, «physicist James Maxwell developed the eponymous equations, describing light as an electromagnetic wave», Fabriani continues. Yet even then, certain issues remained unsolved. «A few decades later», Fabriani recalls, «Albert Einstein discovered the photoelectric effect, for which he won the Nobel Prize in 1921, demonstrating that when electromagnetic radiation strikes a metallic surface, it emits electrons, because light is composed of light quanta called photons, hence of particles». The dual wave-particle nature of light—and consequently of matter—was then formalised by physicist Louis De Broglie in an equation bearing his name, earning him the Nobel Prize in 1929.

Clear and practical evidence of duality

For those unfamiliar with equations, there’s no need to take this on faith. Even in daily life, there are indisputable “proofs” of light’s dual nature. Whenever light appears split into its rainbow of colours, as on the cover of Pink Floyd’s The Dark Side of the Moon, we lean towards the particle theory. Simultaneously, a single slit can make us reconsider, as light reveals its wave nature, producing a pattern of light and dark areas.

«I’m always fascinated by a ray of light’s transformative power as it changes appearance merely by passing through a hole», Fabriani admits.

Aside from the marvel that light’s dual nature evokes, it also provides practical benefits. Fabriani points to the photoelectric effect, which underpins photoelectric cells integrated into alarm systems or automatic gates: «These systems harness the particle nature of light, just like solar panels that, thanks to the photovoltaic effect, convert solar energy from incoming rays into electricity. Both function by leveraging the interaction between light and matter».

The art of bringing light with shadows

Light’s dual nature is not only present in our daily lives but also embraced in the world of art. Some artists have explored this duality scientifically in their work. Fabriani’s book mentions Edmondo Bacci, a futurist artist whose pieces Albe (Dawns) and Avvenimenti (Events) deeply impressed her: «He manages to capture the dawn of light on canvas, like an artistic Big Bang, represented as an explosive burst of initial glow», she explains.

Other artists, however, focus on the interplay of light and shadow. Two Jordanian sculptors, Maysoon Masalha and Bassam Al-Selawi, are among those who make this contrast the centre of their works. «We’ve discovered the transformative power of light and shadow in shaping both the physical form and meaning of a sculpture», they explain. «We are fascinated by their extraordinary ability to transform the ordinary into something magical and intricate, bringing out contrasts and complexities that would otherwise remain invisible». Their works encourage a balance between what is seen and what is unseen, the physical and the abstract, suggesting that “everything has a hidden side”. Exploring the most diverse themes and the numerous human connections between culture and spirituality, emotion, and heritage, Masalha and Al-Selawi aim to «encourage people to look at things from a new perspective and reflect on those levels of life that often go unnoticed».

Learning to coexist like light and shadow

One of the distinct qualities of this artist duo’s creations is their recognition of shadow as an entity in its own right—not merely a by-product of light. This is essential to understanding the dual concept that so captivates observers. «Both light and shadow are active, constructive elements that reshape reality and add new layers of meaning.

In a way, shadow becomes an additional dimension for our 3D sculptures, offering a perspective that goes beyond physical form.

Beyond each sculpture’s aesthetics lies a dual, intangible content: an ancient cultural heritage coupled with the drive for modernity. «Traditional art is a vast source of inspiration. We draw from it to convey messages about identity and spirituality, highlighting the authentic parts of our culture while showing how they can harmoniously coexist with modernity».

Coexistence. The art of creating with both light and shadow, or with light’s dual nature, without needing to choose which is superior or more deserving, carries a profound message that humanity urgently needs. The two artists sensed this message powerfully during their experience teaching young Palestinian refugees in Jordan. «We helped them develop art projects that allowed them to express their feelings and identities through art—a medium that provides space for emotions and stories beyond words», they share. «Working with them has inspired us to explore more human and socially conscious ways of communicating through art, leveraging its profound ability to connect people and convey meaningful messages, especially in difficult circumstances».

Masalha and Al-Selawi’s pieces often inspire contemplation: «People are amazed at how meaning shifts between light and shadow, prompting them to see the world from different perspectives», they say. «We’ve noticed that our work raises questions about reality and appearance, regardless of the viewer’s background». And regardless of the technologies with which they are made.

Embracing both modern and traditional tools to express their vision, the two artists happily experiment with new technologies to enhance their message and emotional impact: «Whether it’s advancements in lighting, materials, or digital tools, technological innovations have often opened up new creative dimensions for us», they say. «Lighting advances have made us more precise in how light and shadow interact within our sculptures, and digital tools support our designs, allowing us to refine our ideas before bringing them to life. For us, it’s about using anything that elevates our art and helps us connect more deeply with people. Technology is just one of the ways in which we can continue to grow and find new ways to tell our stories, but it is always meant to serve art itself».

As in science, light in art suggests embracing coexistence, which means not only accepting duality and “the other” but also recognising their value and capacity to spark innovation, knowledge, and emotion.

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