It heralds Christmas and banishes the darkness for body, mind and soul, it represents truth and hope, and without it we are clumsy awkward creatures. It is the key to life

This time of year is characterised by the dark: we adjust to the dark mornings and to the dusky half-light of mid afternoon. We brace ourselves for more darkness until we are past the solstice. Above all, we pursue that age-old human endeavour to create and use light to fend off the encroaching darkness. Shorter days are usually a subject for regret – and for some it has serious impacts on their mental health.

Light is one of the central metaphors of Christianity. Light is equated with salvation and truth, whereas darkness represents confusion and ignorance, or even worse, hell and damnation. John Henry Newman’s famous hymn “Lead, Kindly Light” is constructed around the metaphor contrasting the dark of night with the “calm light of everlasting life”.

Christianity bequeathed us the concept of “enlightenment” as a term to describe a breakthrough in understanding and wisdom. Other spiritual traditions have a central metaphor – such as fire in Hinduism or spaciousness in Buddhism to describe the liberated mind. But in the northern hemisphere where the dark is dominant for several months of the year, Christianity absorbed many pagan beliefs about the salvific role of light.

Holman Hunt’s painting, The Light of the World, is probably the most popular religious painting of the nineteenth century, and it accentuates the symbolism of light and dark. Christ carries a lantern as he stands by the door knocking, while the rest of the canvas is cast in dark shadow.