the thingness of light


“What is the nature of this invisible thing called light whose presence calls everything into view – except itself?”  [Zajonc, 1993]

There is an uneasiness in describing light as a thing. Scientifically, psychologically or aesthetically, light defies categorization. It interacts with us in a particular manner; we can feel its heat radiating on our skin; but we can’t see it unless it meets a surface. We can cast shadows; but they have no weight. We perceive its presence but it doesn’t seem to obey the rules we live by. We’re then left with calling it neither thing nor nothing. Zajonc’s question underpins a millennia-old paradox concerning light, that we  have recently come to describe as the difference between matter and energy.

“There is a “thingness” to light that one cannot form with one’s hands. Light is not verbal; we need images, we need spaces” [Holl, 2000]

Light as a metaphor can quickly become a cliché, whereas explorations into the objective substance of light have consistently formed foundations for civil advancement in human history.  During the age of enlightenment the scientific understanding of light accelerated with experiment-led research from Michael Faraday, followed by Albert Einstein’s special theory of relativity. However, his widely accepted and precise formula of light did not stifle our capacity to imagine and wonder about light’s nature that has been on our collective consciousness since records began.   

Ancient Greek philosophers, Plato and Euclid, explained light as a consequence of seeing; describing light as the “fire within the eye.” They compared the eyes to lanterns; as if the eyes emitted a kind of “visual ray”, and that the ray travelled at a given speed, explained those strange moments when you looked in the direction of an object but failed to notice its presence immediately. This theory held that the ray “…must strike an object directly before it can be seen”

While this theory might seem irrational, even unhelpful, to a person born in modern times, it does serve to remind us that we don’t have an innate understanding of light. We rely on the cumulative work and knowledge of theorists and scientists, striving over thousands of years to comprehend the laws of physics, which affords us our current, relatively accurate, description of how light behaves. 

Euclid’s theory was disregarded even by his contemporaries after a time. Aristotle was among those to point out: “…if this were true, we’d be able to see in the dark.” 

Aristotle, unfortunately, was not always this clear in his descriptions, “Light is the activity of what is transparent” [Aristotle, c.350 BC] This rather opaque description of light resists comprehension at first, until one compares it to Zajonc’s expression at the start of this section. But perhaps this abstract statement is a fair gauge of light’s enigmatic quality; or more simply, even great minds find that light is a thing hard to describe. 


  1. Zajonc, A. [1993] Catching the Light: The Entwined History of Light and Mind, Oxford University Press, New York p7
  2. Steven Holl, 2000, Parallax, Princeton Architectural Press, p139
  3. The age of enlightenment is thought to have formed around mid nineteenth century
  4. Einstein’s theory of special relativity incorporates the principle that the speed of light is the same for all observers regardless of the state of motion of the source
  5. Joel Achenbach, October 2001, National Geographic, p11
  6. Aristotle c.350, On The Soul, Kessinger Publishing 2004, p34