What I wish to do is sketch a horizon. One could go
through the cultural history of science and gather up examples of
moments in which scientists stood, not confidently, or indeed smugly
in the center of things, pointing out all that they knew with scientific
certainty — the very real things that are, ironically, no
longer central or certain for us — but at the edge of their
knowledge and the limits of their capacities. This edge is the horizon,
the place where the known fades off into the unknown. It is a place
of openness, of vulnerability and danger, and not of institutional
security and confidence. It is the end of the world, a place haunted
by dragons, monsters of the deep, and angels of the apocalypse,
a place for explorers, and not scribes and copiers of received knowledge.
To come to this place where the relationships between imagination
and perception are more clearly dark and ambiguous, the scientists
of the past have often had to come to the edge of their inherited
world and to the edge of their own mind.
