The Phenomenon of Man, by Pierre Teilhard de Chardin, has been characterized as metaphysics, poetry, and mysticism-virtually everything except what its author claimed it was: a purely scientific mmoir.Professor O'Connell here follows up on a nest of clues, uncovered first in an early unpublished essay, then in the series of essays contained principally in The Vision of the Past. Those clues all point to Teilhard's intimate familiarity with the philosophy of science propounded by the celebrated Pierre Duhem. It was Duhem's central claim that science, to remain true to itself, must aim at...