The Irish teacher and poet John O'Donahue writes in his poetic blessing "For Light" of different types of light: neon light, morning light, twilight, moonlight, fugitive light and candlelight. This time of year in nature we're especially sensitive to light (or its absence). Christians think of light in the season before Christmas called Advent (beginning Dec. 1 this year), which long has had light as a major theme. The faithful remember a saying of John the Baptist, whose traditional birthdate is around the summer solstice, comparing himself to Jesus, the light of the world, whose birth date has been celebrated near the winter solstice. John said of Jesus (John 3:30), He must increase, but I must decrease.