This volume contains six new and fifteen previously published essays - plus a new introduction - by Storrs McCall. Some of the essays were written in collaboration with E. J. Lowe of Durham University. The essays discuss controversial topics in logic, action theory, determinism and indeterminism, and the nature of human choice and decision. Some construct a modern up-to-date version of Aristotle's bouleusis, practical deliberation. This process of practical deliberation is shown to be indeterministic but highly controlled and the antithesis of chance. Others deal with the concept of branching four-dimensional space-time, explain non-local influences in quantum mechanics, or reconcile God's omniscience with human free will. The eponymous first essay contains the proof of a fact that in 1931 Kurt Goedel had claimed to be unprovable, namely that the set of arithmetic truths forms a consistent system.