Do we see light?

What is light... exactly?

Light is one of the most diverse phenomena in the universe.
In all ancient cultures, light was considered divine. With the emergence of modern science in the sixteenth century, the cosmic holistic qualities of light gradually began to fade.

Light is typically described as ‘electromagnetic radiation with a certain portion of the spectrum visible to the human eye’. Which brings us to the question: Do we see light? Exciting experiments show that light itself is completely invisible, we only see things, not light – but light lights up everything.1 This definition presupposes that the light is perceived by the eye of the beholder.

Many generations of physicists have struggled to understand light right up to this very day. In modern quantum electrodynamics, the basic theory of electromagnetic radiation has long been expanded upon.

Light combines a variety of phenomena which are not easily explained. Starting with the importance and influence of natural phenomena such as sun and moon, fire, lightning and rainbows on physical characteristics of living organisms (photosynthesis in plants, self-luminous animals such as the firefly and many more), to the scientifically detectable effects and processes of light in humans (how the eye functions, the conversion of light into vitamin D, etc.), to the inner perceptions of the experiences of light which are more challenging to identify and describe, such as the experience of and differentiation of colours.

How can one observe and understand this inner realm, the inner experience of light?

Take for example, the moment a person wakes up. This moment of waking up might be described as an inner illumination, an inner awakening.  Consider how we regularly refer to light in common language:  to shed light or to throw light on something meaning to explain or clarify; a person’s face can light up with joy or excitement, to see something in a new light, to see something from a different angle.

In the following chapters, we will take a look at the natural phenomena of light, the development and consequences of artificial light, as well as philosophical and historical aspects of light. Click here for technical information, general terminology, scientific facts and basic information about light, light bulbs and lamps.


The quality of natural light changes in character, mood and intensity throughout a day. These properties flow like a lively river stimulating feelings and experiences and have undoubtedly always shaped human existence. How do we experience light throughout the course of a day?

Evolution of Artificial Light

Fire, torches, oil lamps and candles served to lengthen days into the night for thousands of years. The discovery of electricity has opened up even more possibilities for keeping out the night for today we can lead lives completely independent of sunlight. How did artificial light come to be?

Effects of Electric Light

Artificial light shapes our daily lives, especially our nights in the big cities. Street lights, large-format illuminated advertising, airport and stadium lighting cause massive bubbles of light over our cities, and they are getting brighter every year. What consequences does this tendency have for nature and man?

1 See the "Eureka" experiment described by Arthur Zajonc in his book "Catching the Light" (excerpt here) and astronaut reports on the dark universe. See what comes up when you ask the question: “Why is the universe dark?” The question is far more complex than one might first assume!