The importance of light

2015 is the International Year of Light (see for more about it). This is an international celebration of the importance of light in science, technology and human life.


Light is essential to life on earth. Without it, there would be no photosynthesis, the process by which plants create and store sugars and, in turn, to be useful as food. Oxygen is, of course, a by-product of photosynthesis so light even allows us to breathe, be it indirectly. The light of the sun isn’t just needed by plants. We need it in order for our bodies to make vitamin D.


What we most often think of, I suspect, when we consider light is that it allows us to see. This has made light a valuable tool for science. Telescopes, for example, capture and magnify light, making distant objects visible, and have made it possible for astronomers to study the planets in our own solar system, distant stars and even other galaxies. Isaac Newton was fascinated by light, and did several now well-known experiments with it, notably his experiments with refraction. Newton’s work on the spectrum (the colours that make up white light) paved the way for fields of science such as spectroscopy - looking at light broken apart into its component colours. Spectroscopy is used quite a lot by astronomers. Different elements absorb and reflect different wavelengths of light (equating to different colours), which makes spectroscopy a useful tool in determining the chemical make-up of distant stars. The development of fibre-optics – directing light along a thin cable - has revolutionised communications technology and been extremely useful in medicine.


As well as being central to several areas of science and technology, light has always been important within the Judeo-Christian tradition. In the creation narrative of Genesis 1, the first thing that God creates is light. In his retelling of this creation narrative at the start of his Gospel, John writes, “In the beginning was the Word, and the Word was with God, and the Word was God. He was in the beginning with God. All things came into being through him, and without him not one thing came into being. What has come into being in him was life, and the life was the light of all people. The light shines in the darkness, and the darkness did not overcome it.” Life and light are inextricably linked, and this is both a physical and a spiritual reality.


Light is an important theme throughout John’s Gospel. Light and darkness are used as metaphors for understanding and ignorance. Nicodemus comes to Jesus by night, and in the conversation that follows, Jesus expresses his dismay that, although a “teacher of Israel”, Nicodemus doesn’t seem to understand basic spiritual realities. At the end of the Gospel, Mary Magdalene comes to Jesus’ tomb, “while it was still dark.” She is, as yet, ignorant of the resurrection – and even when she discovers the empty tomb, remains in the dark about its significance. But as the resurrection story unfolds, and the day moves from the darkness of early morning to dawn, so understanding grows, and the disciples believe. Christianity doesn’t have a monopoly on this metaphorical use of light. We speak of the 17th century as The Enlightenment – a period when knowledge of the physical world and the sciences blossomed. Ignorance and previously held suppositions were replaced with knowledge based on observation and experimentation. Sadly, some have come to equate the darkness of ignorance that went before the Enlightenment not with a lack of scientific knowledge, but with religious faith. But that’s a false comparison. The lack of knowledge that preceded the Enlightenment wasn’t caused by religious practice or belief in God. It was, instead, simply that the tools by which the world could be more accurately studied, and therefore more comprehensively understood, hadn’t been there.


Now is a good time for the Church to be thinking about the importance of light in the Christian story. At Easter we will light the Paschal Candle – the light that represents Christ’s resurrection from death and the light of new life coming into the world. This is yet another retelling of the creation story, but this time, what has been made is the first light of the new creation – the promise of greater things still to come.


The light of spiritual knowledge and the light of scientific knowledge can - and should - both illuminate our understanding of the world. Scientific knowledge shows us how the world works; spiritual knowledge shows us how to live in that world. Both give us light to see by as we journey through life.

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