One of the greatest and oldest of images for expressing living change is that of the movement of waters. Rivers particularly, in their relentless motion, in the constant searching direction of their travel, in the confluence of tributaries and the division into channels by which identity is constituted and dispersed and once more reestablished, have stood as metaphors for movements in a variety of realms-politics, religion, literature, thought. Among philosophic movements, phenomenology and existential ism are discernible as one such movement of ideas analogous in configuration to the flow of...