David R. Law, The Historical-Critical Method: A Guide for the Perplexed (London: Continuum, 2012), 43.
Johann Salomo Semler (1725-1791) was a pupil of [Siegmund Jakob] Baumgarten and took the next logical step by dropping Baumgarten’s notion of the supernatural understanding of Scripture and arguing for a biblical interpretation free of doctrinal presuppositions. It was with Semler and his contemporary Johann David Michaelis (1717-1791) that the historical study of the New Testament came into its own. Indeed, Semler is sometimes described as the ‘father of historical-critical research.’
In his Historical Introduction to Dogmatic Theology (1759-1760), Semler distinguishes between ‘outward’ and ‘inward’ religion. Outward religion is the public form of religion practised by a community of faith and includes its rituals, clergy, and traditions. For Semler, this outward, public religion is characteristic of all religions, including faiths such as Judaism, Islam and Hinduism. Religious differences are due merely to the local, historical traditions which have moulded the distinctive practices of the outward religion of a particular faith. Private religion on the other hand is ‘inward’ and ‘moral.’ This distinction between outward and inward religion and his view that outward religion is historically conditioned allowed Semler to treat the Bible as a historical artefact. The Bible should not be treated as a unified work containing timeless truths, but as a collection of works which bear the mark of the historical period in which the biblical writings were composed. This insight opened up the possibility of treating the books of the Bible independently of the interpretive framework provided by the canon into which they had been incorporated by the Church.