The moon has no light of its own. And while we can see the sun, we cannot see its light. It is when the light of the sun meets an obstacle upon which that light then reflects that we know that both the light and the obstacle are there. We would not know that the moon is there were it not for the light of the sun and conversely, we would not know that there is light from the sun were it not for objects such as the moon that it illuminates. We cannot see light any more than we can see wind. We only see its effects.
As sentient beings, we evolved within a narrow spectrum of reality, our environment, to navigate it using among other things light. By the shade and shadows cast by opaque surfaces under the light of the sun, we can tell where we are in relation to the things around us—the ground and objects (or “figures”) that inhabit it. And even now, with clocks, we still tell time in relation to how and when opaque objects occlude light. We sense the time of day (morning, noon, afternoon and evening), what day it is (new, quarter, half and full moon) and here in southern California, the season (winter, spring, summer and fall).
Relationships among the opaque objects around us and ourselves with them are fundamental to our sense of orientation in the world and our survival in it. We depend on opacity. Not every object or surface in the world is opaque in the same way (texture, color) and that is how we know what they are made of. Some, not a lot, are not opaque at all-- they are, rather, translucent, transparent, refractive and reflective-- some so transparent that under certain (somewhat rare) light conditions they disappear altogether.
Those qualities that we appreciate in the reflection off a mountain lake, the refractions of light and color from precious jewels and metals, the interplay of varying translucency in the interactions of water and air across days and seasons (mists and clouds at sunrise and sunset) are their rarity and ephemerality. They are transcendent by virtue of their ability to unmoor us from the mundane gravity ladened world we live in.
Before not long ago, most buildings were mostly opaque. They were built of and finished with common and readily available materials taken from the earth (soil, wood, stone). The extent to which buildings had openings (doors and windows) depended on the in-born structural qualities of those materials--qualities that nature, not engineering, had bestowed, openings which by contemporary standards were and are limited and limiting in extent and experience.
With the advent of manufactured materials, such as steel and glass, we came to conceive buildings that were mostly translucent, transparent, refractive and reflective. We got more (or less?) than windows in walls, we got walls of glass. Instead of buildings and rooms shrouded in the dark, we enjoy interiors abundantly lit by the light of day—and with the right light, a seamless visual continuity between inside and out. That we have benefited is without doubt, but have we also paid a price?
What began in the 19th C as an earnest effort to apply new technologies and materials to improve construction efficiency and broaden our repertoire in building design morphed in the 20th C into rarified hyper intellectualized experiments intended to contrast with and transcend what by then had come to seem mundane—dense massive buildings punctuated by small apertures and dark interiors with (relatively) little light. Not long thereafter in the mid-century, as those experiments congealed into dogma and the economics of construction increasingly relied more on manufacturing and less on labor, we got glass and steel buildings, not as something special in distinction from their settings but as the default setting of our surroundings.
Nature is nearly always our best teacher and we would be right to wonder whether within our built environment (which to be sure is not a natural environment) the increasing deficit of opaque surfaces is nevertheless lamentable. We forget to appreciate the simple beauties of volumes lit by the sun, the gradations in lighting, shade and shadow that come with the varying orientations and shapes of surfaces and the sense of clarity, stability and permanence that comes with an opaque environment reassuring in its unchanging presence.