Cobb, John B., Jr.  "The Philosophy of Charles Hartshorne."  Process Studies 21, no. 2 (Summer 1992): 75-84.

Abstract

Hartshorne's extraordinary contribution to twentieth-century philosophy has been recognized by Volume XX of "The Library of Living Philosophers".  This volume shows the breadth and depth of his contributions - from philosophical studies of physiological psychology and bird song to metaphysics and philosophy of religion.  At the age of ninety-six he is still writing.  He differs from Whitehead by adopting a more rationalistic approach.  He resolves the dualism of the mental and the physical by opting for physicalism, whereas Whitehead proposes events that are both mental and physical.  [Abstract from The Philosopher's Index]