From the time of the ancient Greeks, we have been counseled: “Know thyself.” As if we could. And yet we know instinctively that the advice is right. We should know what moves us, what we truly desire, the limits of what we can know, what we really believe and really do not believe, what we are in doubt about, all the bets we are willing to hedge. And even after we have made a thorough inventory of all this, we will have only scratched the surface.

I put the whole sense of self-knowledge in the strange and tangled context of dreaming. Since I was very young I have had vivid and strange dreams, dreams so powerful that I have often wondered which of my memories are true and which come from dreams. In some dreams I remember dreams from other dreams, or seem to, as if I had a separate dream-world self with its own dream life. My dreams involve cities, landscapes, philosophies, religions, people I have never known in my waking life. This world is in some way larger and stranger than the one I inhabit consciously, stranger for obvious reasons (since one person or place so easily morphs into another), and larger because spatial and temporal boundaries are not as confining.

In one dream the moon is covered or replaced by a shining skull. In another, my father and I travel the world, pursuing rumors of a hieroglyph that is somehow vital to the life of the world and appears on walls and cliffs, and we always arrive too late to see it. In another, someone I know, with whom I have had a difficult relationship, appears weeping, saying “You have no idea how lonely I am.” This dream in fact changed my relationship with her in real life, for the better.

It isn’t wise to make too much of dreams, or to see them as always significant. But they do show us that the borders of the self are strange, and much wider than we usually think they are. They show us that we are like a planet only half inhabited, with whole undisclosed continents. Our practical day-to-day self is a little afraid of this, or maybe more than a little, but this dream dimension is an essential part of who we are—and of everyone else who, whether he or she knows it or not, carries the same unbounded fullness. The unknowable parts of ourselves and of everything around us have to be set aside in our moment-to-moment engagement with the world. They have to be hidden so that we can get through the day, swinging from one necessary tendril of perception to another, like an ape going from branch to branch, a whole deep jungle around us. We could not, in our present limited state of consciousness, proceed if the whole of what we live in were fully present to us.

Here I think of Gregory of Nyssa’s wonderful observation: Concepts create idols; only wonder comprehends anything.

As a practical measure, we need concepts, limited images, maps, momentary and fleeting impressions. But stopping there—acting as if this were as deep as it gets—is not only a mistake but a tragic diminution of consciousness. This sense of wonder goes beyond consciousness to the world of the objects that lie beyond us, all of the natural world surrounding us. Science, seen properly, leads to wonder. When I was a child I loved reading about science, and my first serious encounter with perception and its limits came when I read about light and about the parts of the spectrum our eyes can’t take in. There was a tree I loved in a field across the street from our house. I loved the tree not only because it was beautiful but also because it was a perfect climbing tree, its branches placed just right to get you from the ground to the top. When I read about the spectrum I realized that I was limited to seeing only part of the tree—the part of the spectrum my eye could register. But also I could only see the tree from one side or another, from the vantage point of a short nine-year-old, looking at it from, say, the north side. If I were a giant standing directly above it and it was small to me, like a broccoli spear, it would seem very different. Furthermore, time limited my “seeing” it: the tree went from seed to decay, but I was there for neither the tree’s beginning nor its end. So I wondered about the mystery of the tree in itself: What was it apart from my seeing it? What was it in God’s way of knowing it?

This sense of the limits of knowledge can bring us into a place of wonder, gratitude, and humility. I think of Paul, in speaking of what we are to become (1 Corinthians 13:12): “For now we see through a glass, darkly; but then face to face: now I know in part; but then shall I know even as also I am known.”