Hans von Campenhausen
Hans Von Campenhausen, building upon Harnack’s reconstruction of Marcion, argued in The Formation of the Christian Bible that scholars cannot speak of a ‘canon’ of Pauline epistles before Marcion, as there was no normative collection of new writings or scriptures prior to his collection. Von Campenhausen understood Marcion’s primary tension to be between the law and Christian faith, and that he created the formative “Gospel and Apostle” canon format, using the writings Paul as the essential teachings in salvation-history. He argued that Marcion found his authentic gospel behind Luke’s writing because it posed the fewest questions and modifications for his theology. Von Campenhausen concluded that Marcion’s canon, with its Gospel and Apostle components, forced the creation of what became the New Testament canon of the Great Church by forcing them to answer questions about new revelation and writing. He argued that the church’s adoption of the Pauline Epistles and four Gospel accounts were directly influenced by Marcion’s use of Paul and his single gospel text. Thus it was not until after Marcion that Irenaeus of Lyons became the first Catholic theologian to accept the Marcionite principle of new scripture. Thus for Von Campenhausen, Marcion’s rejection of the Jewish scriptures because of his understood tension between law and gospel necessitated the formation of a new set of writings. His adoption of the “Gospel and Apostle” format eventually influenced the shape of the Christian Canon as it began to influence the sources accepted as authoritative by the proto-orthodox.
While Bruce Metzger did not entirely concur with the conclusions of Harnack and Von Campenhausen regarding Marcion’s influence on the formation of the canon, his perspective best fits within the Canon Formation school of thought. Metzger argued that something resembling a Pauline corpus of letters began circulating early on within the Christian tradition, quite possibly during Paul’s lifetime. Thus in one sense Marcion could not have been the first to originate a collection of new Christian writings. Additionally, Metzger argued that some of the letters of Paul and Gospel materials were being used and cited as authoritative as early on as the writing of First Clement in the late first century. However, Metzger ultimately argued that heretical perspectives forced the Great Church into forming a full-fledged practical, and eventually formalized, New Testament Canon. The formative perspectives for Metzger involved not Marcion alone, as could be deduced from Harnack and Von Campenhausen’s positions, but rather due to the combined influences from Christian Gnostics, Montanism, and Marcion’s canon. Thus Metzger conceived of a canonical process that, while neither entirely beginning with Marcion’s canon nor exclusively being influenced by him, nonetheless came about in the early church as a result of Marcion’s influence.
 Hans Von Campenhausen. The Formation of the Christian Bible. Translated by J.A. Baker. Fortress Press: Philadelphia, 1972. 145-6, 148.  Ibid., 153-4.  Ibid., 157-60.  Ibid., 163-5.  Ibid., 170-84.  Ibid., 186.  Bruce M. Metzger. The New Testament: Its Origins, Background, and Content. Abingdon Press: Nashville, 1965. Print. 274.  Metzger Canon, 40-43.  Ibid., 75-112.  Ibid., 75.