Christians have wrestled with conscience from Christianity’s beginning to the present. Does it exist? Do religious and nonreligious people have it? Is conscience a subjective or objective reality? Christians have asked if it is God’s voice, human beings’ own voice, or the voice of the community. Is conscience found in natural law? Is it a combination of the mind, will, heart, and/or the soul? Is it a divine judgment or a self-evaluation? What are the consequences of following an erroneous conscience? Lately, questions have arisen about conscience in a pluralistic society. What ought to be the relationship between conscience and law? Commentators also struggle with questions about accommodating institutions’ conscience claims. Which institutions might qualify and why? Lawmakers also contend over conscience claims made by individuals concerning military service, or over state laws about family matters increasingly at odds with Christian commitments. This book explores sources having lasting influence upon questions about conscience, including the New Testament, Aquinas, Luther, Calvin, Roger Williams, US federal and state constitutions, and Pope Benedict XVI, among many others.