In my room atop Lowell House, studying for exams, I take time off to reflect on the generalities and fragments of my educational experience. Reading through my notes--often hasty and incomplete scrawls--I can nonetheless close my eyes and immediately see the attendant lecture on the blackboard before me.

My scrawls are a shorthand for blackboard writing--itself the professor's shorthand--and from this the ideas come flooding back. (Thus I know that the blackboard is involved in what I know.)

So if one were to ask, in the usual sociological way, what relic an alien culture might use to intuit our pedagogy, my vote for the blackboard would be immediate. Here is an artifact whose interdisciplinary presence is rivaled only by the desk and the pencil. Greek classes, French classes, math classes and Core classes all revolve around its inimitable black surface. Professors and TFs--who do not speak the same language--will, in their turn, pick up a piece of chalk and begin to write.

My blackboard-heavy experience is in part due to Harvard's great blackboards: the room-wide expanses of Sever's corner classrooms, the perfectly automated n-piece boards of Maxwell Dworkin, the unfinished lemmas on the wall of the math lounge, the nearly square boards in the string theorists' fourth-floor playground.

Likewise, I have suffered through notorious blackboards: the bobbing layers of Geological Sciences Laboratory classrooms, the odd lighting in Science Center D, the squeaky free-standing board on the Science Center's eighth floor. (Among 20 students, the only thing moving was the edge of the blackboard.)

But the very idea of erecting an erasable surface for the explanation of concepts goes far beyond aesthetics. Its dual names--blackboard, chalkboard--reflect a changing emphasis on the surface and the tool of writing. From its size and placement, its inherent economy of scale, we intuit a notion of ideal class size: fifteen students can be taught as easily as one, but double or triple this and the precision of chalk-shapes becomes difficult to read.

At the same time, the blackboard points to an education which is continually supplanting itself. In the course of an hour's lecture, it must be erased regularly, as ideas are continually grasped and give way to new ideas. In this strange reversal of roles, it becomes the speech of the lecture, and not its written manifestation, which is "permanent."

Thus the strange inaccessibility of blackboard fragments: Slavic grammar left from a previous class, six contextual uses of "tre," metaphor underlined six times, the outlines of tensor products hidden beneath organic compounds. Who is to say what these meant to the people in the room before us? The blackboard, unlike a book, rarely contains an explanation of its own context; its fragments are as foreign to the observer as pieces of a telephone conversation caught in an instance of crossed lines. (It is a small part of the pantomime.)