We often have a mistaken idea about enlightenment. To enlighten is to light up. To shine a light on. Many People seem to have the idea that to enlighten or shine a light on is an active sort of thing. Like shining a flashlight where you hear a noise in the dark. This makes the assumption of course, that the light you have to shine has to be turned on, and directed. Many people are engaged in an attempt to turn on the light.
Zen has a different idea. When you just sit, what you begin to see is that deep inside there already is a light. There is something there that perceives. There is an unblemished Buddha nature inside. Some liken it to a seed, I liken it to a star. In our life we go about actively trying to bury this light in junk that we accumulate. We pile on opinions, experience, knowledge, material goods, responsibilities, fears, impressions plans and perceptions. We try and control the light, and frame it and shape it till it can shine only one direction, we build a box around the light, so it can shine in only one way, and then we try and build another box so it can shine in only another direction and we do this again and again until no trace of that original light can be perceived.
We end up calling this nest of boxes "me", but this is not true. This nest of boxes is something we accumulate and create. If we create it, it cannot be who or what we truly are. Even the inside voice that humms the tune that shapes the boxes is only an accumulation of of debris. This light existed before the baby had language to give voice to the words that it whispers inside our head. It existed before the small voice inside uttered its first word. It existed before the small voice inside our head began to whisper of fear, and inadequacy, and the horrible things that might happen if we just let go of the boxes that contain us.
Shikan-taza is about opening the boxes. Well, more accurately, it is about getting rid of the boxes. It is about putting down the boxes until there are no more and the light that was inside the boxes just shines in every direction. It illuminates all things, like the sun having finally come out from behind the clouds.
Perhaps the idea that we should become enlightened, is just a bad translation. Maybe what the translators should have said is that we must become enlightening. We must become awake to the piling of trash on our original Buddha nature.
Dogen said practice is enlightenment. The whole of the practice that Dogen describes includes a lot more than just zazen. It includes the whole of your day, the whole of your week, the whole of your life. In each moment we must sweep clear the accumulation of debris from our life that covers up and obscures the light. Enlightenment is not some turning on of a light that did not already exist. It is the ceaseless sweeping clear of the debris of life so that the original light can shine on all things, even this bag of bones we call a body. This is why practice is enlightenment.
We must eventually even sweep clean this accumulated idea, and just shine on each and everything that comes to us. We will then illuminate the dark corners, and bring a fresh and healthy nourishing light to each thing and every place we go. We just need to let our original nature, our face before our parents were born, shine unobscured.