Then the people stood at a distance, while Moses drew near to the thick darkness where God was.
(Exodus 20:21)
You may remember “rods and cones” from high school biology. These are the photoreceptors in your retina that absorb light and transmit signals to your brain. You can think of them like the pixels in your eye camera. Rods absorb low light and let us detect brightness. They are most effective for our night vision, and when you walk by the light of the moon, you see everything in shades of silver and gray. Cones detect color and more subtle differences; when the sun rises, the world is crisper and colors pop.
In addition to rods and cones, your retina contains the melanopsin system. Melanopsin is a photopgiment that was first discovered in light-sensitive frog skin, before we discovered receptors in our eyes that use the same chemical. It is crucial to the function of clusters of nerves called “intrinsically photosensitive retinal ganglion cells” (ipRGCs).
These nerve clusters transmit directly to parts of your brain responsible for your circadian rhythms, interrupting the production of melatonin (which makes you sleepy). One of the odd side effects of this system is that some people who are image-blind can still regulate their sleep cycles to the sun! In other words, they can’t “see” images, but their brain knows when the sun is shining.
There has been a lot written about the way light—natural and artificial—affects our sleep cycles and moods. We are spending more time inside, not only because of the change in the weather but because of the pandemic. Human biology evolved to be outside, and many of our modern psychological problems are made worse by exposure to screens. As our physical activity level goes down (and it’s usually lower in the winter), we get fewer opportunities to produce natural mood boosters. We are not sleeping as well. We are stressed. We are in brain fog. And the darkness exacerbates all of it.
A lot of this seasonal moodiness is natural. Our bodies are responding to a change in the seasons, telling us to conserve energy because wild forage will not be as abundant. We feel more drawn to carbohydrate-heavy foods. We want to snuggle with loved ones, not just for warmth but for comfort. All of this is natural and helped our ancestors stay alive. But it becomes a “disorder” when it makes it hard for us to function.
I think it’s important not to pathologize these natural experiences of being human, but at the same time to recognize some of us are especially sensitive to this seasonal change. There are some things we can do to help, and you may be familiar with them: getting outside, especially in the morning, to let the morning sun regulate our melatonin production. Staying off screens a few hours before bed. Using special bright lights to give us an artificial “sunshine boost” —again, especially in the morning. We purchased a “happy light” last year and I think using it makes a difference.
But I think it’s also helpful to reframe the darkness, to see it as a friend. There has been a trend in theological circles lately to rescue “the dark” from its religiously negative connotations. In the passage above, and in several Psalms, the authors describe God as dwelling in “thick darkness,” a darkness so deep you can feel it. These mystics describe the darkness as the place of germination, where buried seeds send out their first tender filaments to probe the rich, dark soil. It is the darkness of the womb, where we first hear our mother’s heartbeat. It is a place that forces us to rely on other senses besides sight. Darkness can be healing. Darkness can be welcome. It is in the “valley of the shadow of darkness” where the author of Psalm 23 says God guides us with rod and staff, giving us comfort.
If you feel thick darkness around you this season, in this winter of COVID, remember that it’s in the darkness that God does some of God’s best work.
Also, put on a coat and get outside.
Prayer:
Dweller in Darkness and Source of All Light, walk with us in both night and day.
—Rev. Dr. David Barnhart, Jr.
Dave Barnhart 
