When I wake in the wee hours of the morning, the darkness comforts me. It is heavy, grounding, peaceful. The stillness is alluring. I turn on as little light as possible to protect my ostensible solitude. Darkness invites me inward, a natural encouragement toward pratyahara, the practice of withdrawing the senses. And as the business of life falls away, if only for a moment, my being is allowed freedom to explore questions such as the purpose of life, and what is it that I really love (different versions of the same question really.) If only for a moment, clarity seeps into awareness.
Yoga does not dispel the darkness. Yoga illumines the darkness.