GEOMETRY. During the last two millennia BCE, the period that produced most religious texts, geometry (lit., "earth measurement," from Greek gaia, ge, "the earth," and metrein, "to measure") was essentially a "geometrical algebra" with a focus on number. Problematic allusions to number and space, which abound in sacred texts, are presumably inspired by this early mathematical protoscience. During the much later development of Christianity and Islam, Euclidean geometry—based, so it seemed, on irrefutable deductive logic built from definitions, postulates, and theorems—became the rational paradigm for all sciences, including theology. The discovery of other geometries in the last two centuries has brought the realization that Euclidean geometry is merely a special case within a wider realm. Efforts to rid mathematics of its logical paradoxes have taught that perfect consistency and certainty are unattainable in rational thought. These developments, together with a new awareness of the complexity of...