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.

In this chapter, I address important preliminary challenges to any discussion of deontic principles in ICL. Thoughtful scholars have raised concerns that familiar liberal principles may be entirely out of place in ICL. I will argue: (1) For any system that chooses to punish individuals, deontic principles do matter, and thus they should constrain ICL. (2) This does not necessarily mean replicating formulations of fundamental principles familiar from national systems; instead we can return to our underlying deontic commitments and see what they entail in these new contexts. (3) We can learn from common critiques of liberal accounts, to build a sensitive, humanistic account of deontic principles.

In response to various criticisms of criminal justice and liberal principles, I emphasize the ‘humanity’ of criminal justice. Criminal justice and its restraining principles are sometimes portrayed as abstract, metaphysical, retributive, vengeful, Western, or ideologically unmoored from experience. But criminal law serves pro-social aims. Its constraints are rooted in compassion, empathy, and regard for humanity. An intelligent liberal account considers all facets of human experience, including social context, social roles, and collective endeavours. Principles reflect broadly shared human concerns, and can be refined through human conversation.