Positions in the ongoing debate about free will are characterized and compared, that is, determinism, indeterminism, chaoticism, stronger and weaker versions of indeterminism and chaoticism, and hard and soft determinism, and libertarianism. Libertarianism is claimed to be the most adequate of these alternatives and is defended from the process perspectives of A. N. Whitehead, Charles Hartshorne, and the psychologist-philosopher William James. The defence is developed by responding to three objections to libertarianism: (1) that scientific explanations in psychology and other disciplines (...) require belief in causal determinism; (2) that indeterminism, assumed by libertarianism, makes impossible moral or other kinds of responsibility for human acts; and (3) that libertarianism must assume an untenable mind-body dualism. The article concludes that liber4tarianism is a more subtle and cogent position than most of its opponents have recognized, that determinism has glaring deficiencies of its own, and that libertarianism is an appropriate position for psychology—even for a scientific psychology. (shrink)