One could ponder this line for a long while, but I will interpret it thus: It is what we don't know that infuses the world with beauty.
The sudden and unexpected lover's touch that comes out of the blue. The extravagance of a sunset that seems to overwhelm the laws of reflection, scattering and refraction. The exquisite aerodynamic perfection of the dragonfly that lands on a fingertip. Even the perception of beauty itself, which, so far at least, defies the neurologist's understanding.
The usual, the well-understood, the commonplace, seldom move us to ecstasy. It is the inexplicable occurrence, if benign, that warms the heart and drops the jaw.
Mystery is the mother of beauty.
In his book The Language of God: A Scientist Presents Evidence of Belief, Francis Collins tells us how he found God:
On a beautiful fall day, as I was hiking in the Cascade Mountains during my first trip west of the Mississippi, the majesty and beauty of God's creation overwhelmed my resistance. As I rounded a corner and saw a beautiful and unexpected frozen waterfall, hundreds of feet high, I knew the search was over. The next morning, I knelt in the dewy grass as the sun rose and surrendered to Jesus Christ.I don't want to belittle Collins' epiphany. Many of us have had similar experiences, moments when the inexplicable overwhelms us. It is the response that separates us. Collins gives the experience a name, a personhood. One might argue that he transfers the experience of his own personhood onto the mystery. He is confident he has found the well in the desert. In effect, he has replaced the mystery with the commonplace.
The Little Prince might say that the beauty of the waterfall arises precisely because its source cannot be named, that it eludes every metaphor.
The greatest discovery of science is ignorance, an awareness of how little we know. Every extension of knowledge -- such as the sequencing of the human genome, which Collins led -- extends the shore where we encounter the sea of unknowing. What makes the desert beautiful is that somewhere it hides a well.