Introduction

A major source of division in Christianity concerns the source of moral principles and the relative authority of the Bible, Church and reason.

Early Christianity had no single unified institution with an agreed New Testament. Instead, it developed organically across geographically scattered communities. Different churches inherited different apostolic traditions and circulated different gospels, letters and other Christian writings. These writings were increasingly brought together and their authority debated as the organisation of the Church developed, with its structure of bishops, councils and shared doctrine. Over the following centuries, agreement grew around the books that became the New Testament canon. Scripture and Church authority therefore developed together.

Medieval Christianity increasingly developed a role for reason alongside Scripture and Church tradition. Theologians such as Aquinas systematised this approach, arguing through natural law that human reason can discover basic moral principles. Catholic ethics therefore came to combine Scripture, Church tradition and reason as sources of moral guidance.

The Reformation challenged this Catholic framework of authority. Reformers criticised corruption within the Church and were suspicious of treating unaided human reason as an independent source of Christian moral truth. They concluded that Scripture is the supreme earthly authority by which Church teaching must be judged (sola scriptura). Protestants and Catholics generally agreed that the Bible was God’s word, but disagreed over the authority of the Church and tradition.

The Enlightenment greatly increased confidence in independent human reason and encouraged traditional religious authorities to be questioned. Scientific, historical and literary criticism increasingly revealed the Bible’s human authors, sources and historical contexts. Later moral criticism also questioned whether teachings on issues such as slavery, women, violence or sexuality could express the timeless will of an omnibenevolent God. Debate therefore increasingly concerned not only the Bible’s authority, but what kind of book it is. A liberal/subjective view of inspiration emerged which regarded biblical teachings as partly reflecting human culture and limitations. This increased the role of reason in deciding which teachings remain authoritative and, alongside political liberalism and growing emphasis on individual responsibility, contributed to greater autonomy in ethics.

The result of this history is three main views on the source of moral principles, and two main views on the nature and authority of the bible:

On the source of moral principles:

Heteronomy (other-law) means the moral law comes from a source outside the individual’s own independent judgement.

• Catholic ethics has a strong heteronomous element because Scripture and authoritative Church tradition determine individual moral judgement.
• However, its use of natural law and reason also gives it an autonomous element.

Theonomy (God-law) means the moral law comes ultimately from God.

• Sola scriptura is a common Protestant form of theonomy.
• The Bible is treated as the supreme revealed authority, above Church tradition in cases of conflict.

Autonomy (self-law) means individuals must themselves use rational judgement to determine what morality requires.

• Aquinas introduced a limited form of autonomy into medieval Christian ethics through natural-law reasoning.
• The Enlightenment later pushed autonomy much further, especially in Kant, who made rational moral judgement substantially independent of revelation.
• In the twentieth century, Fletcher’s situation ethics likewise gave individuals substantial autonomy in deciding what agape requires in each situation.

On the nature and authority of the bible:

The conservative/objective view of inspiration holds that the Bible itself is genuinely inspired by God and communicates God’s word.

The liberal/subjective view of inspiration understands the biblical text primarily as human interpretations or expressions of encounters with God.

Today, Christians combine these approaches in different ways:

Type of Christian	Source of moral principles	View of the bible
Conservative protestants	Sola scriptura Theonomy	Conservative/objective inspiration
Conservative Catholics	Heteronomy	Conservative/objective inspiration
Liberal Christians	Autonomy	Liberal/subjective inspiration

These are tendencies rather than fixed combinations, since a view of biblical inspiration does not by itself determine how Scripture must be interpreted or applied ethically. Christian approaches can also overlap. Catholic ethics gives an important role to autonomous reason, while liberal Christians may retain forms of biblical or Church authority.