Since I’ve been researching what darkness means—what it means to dive into dark depths and exploring those hidden places of spirituality and human-ness that are so unnerving they are considered mythic, I was fascinated to learn recently about something quite human and relatively normal: the pineal gland. This gland, which I vaguely remember from high school biology as being a fingernail-sized gland above the brain stem, is also called "the third eye” and is associated with telepathy and the seat of the soul. It is considered the place from which we see the brightness of our futures and recognize our potential from the darkness of uncertainty. But I was surprised to learn that the pineal gland actually has photoreceptive rods and cones just like the retina of the eyes. The pineal gland, tucked deep into the folds of the brain and nowhere near the eyes, is what allows us to perceive, while asleep, whether it is day or night, and it makes me wonder: How do we perceive dark—the real Dark, with a capital D?

How does a darkness so mythic and powerful as the dark of unknowing reach into our minds and even our souls? Darkness is a part of our lives—we call it various names, including uncertainty, confusion, sadness, and grief. We call it fear and trepidation and danger. We have common phrases such as “afraid of the dark” and we use darkness to symbolize bad things (unfortunately at the expense of dark-skinned people who bear the brunt of a limited vocabulary of symbols). We install light bulbs in every room, carry cell phones with built-in flashlights, and we generally work to “shine a light” for others.

Which is all very good. But darkness has its place too, especially when we are working to understand ourselves, or to create a shift in our lives, or to transition from one state-of-being to another. These shifts and transitions are dark experiences lacking clarity and structure. And here is this little gland in the body that rides around in our brains with us, helping us perceive whether it is day or night, light or dark, stop or continue, yes or no. I’m inclined to think that this hidden jewel of the brain is not only a night-time regulator but also the source of the deep, overwhelming sense of imbalance and extraordinary "lightness of being" and loss of firmament that we experience when, for instance, we go caving.

I used to go caving (spelunking) a lot in grad school; I loved donning thick wool pants and helmets with carbide lanterns or battery lamps and descending into the depths of various caves throughout the Appalachian mountains. Some of the caves we explored were very small and tight, often nicknamed “birth canals” because they led us into the heart of the earth, squeezing through narrow openings of slick rock into darkness and wetness, surrounded by the erie sounds of dripping water and the echoes of our own bodies scraping against the rocks. But other caves were grand caverns--giant extraordinary rooms with tunnels and passages that went miles into the darkness, whose distant points have never been reached and where saber tooth tiger bones have been discovered from unfortunate animals that fell in long ago.

The darkness in these deep caves is hard to explain--it goes beyond dark to a sort of pitch black experience that unnerves you. I remember blinking repeatedly and trying to get a hint of some glimmer of light but there was absolutely nothing, no point of reference or shape of an object or anything to give you a sense of whether you are up or down or sideways. Gravity seems twisted. It's a frightening yet liberating feeling that is almost an out-of-body experience.

I've wondered before if an unborn baby can sense the light of the outside world through the mother's belly; it seems that light must penetrate in some way and that the pineal gland would develop its extraordinary sensing ability during this phase of growth, allowing us as children and adults to sense the rhythms of the world using the special senses of our inner eye.

But in a cave! The dark of a cave is the epitome of an idea even more dreaded than sadness or grief or uncertainty. It is the darkness of death itself, and it makes our minds and souls push the boundaries associated with non-being and explore what the transition of death might mean for us, because when you are in the depths of a cave you are faced with the beauty and the terror of a darkness as you have never known. It is exhilarating to feel the crush of dark and the expansion of thought and perception in a way like never before, in a way in which your body is secondary and your perception of timeless and limitless spirit is primary.

And despite the fear, we humans need this totality of dark. We need silence and downtime and we even need uncertainty and confusion and sadness and grief. These are elements of our souls that challenge us and ultimately make us stronger.

Dark is the Mother Cave. It is the womb. It is where we go when we need to sort things out and grow. It’s where we began and it’s why we continue. It’s what stimulates us to question, Who am I and What shall I do next? Dark is an innate part of ourselves—our personal selves as well as our collective selves, since humans have lived through eons of pitch-black nights and have questioned our purpose in the shelter of countless welcoming caves and in the abiding embrace of our Mother’s arms. Dark is central to who we are. We should not be afraid of dark, of silence, of unknowing; we should embrace it as the part of our lives that makes light worth it. It makes certainty and vision and creativity and understanding worth it. Without dark, we would have no way of knowing which way is up and which path leads forward. Because without dark, we cannot appreciate light.