One of the main difficulties in the debates between Protestants and Catholics is the differing definitions of tradition on offer. Muller, quoting Heiko Oberman, can help us here.
For Oberman, the question of authority in the later Middle Ages rests not so much on differing views of Scripture as on differing views of tradition. There was, in fact, an “encounter,” according to Oberman, “of two general notions about tradition.” In one view, Scripture is identified as the unique source of revealed truth and, therefore, as the sole norm for the understanding of Christian doctrine, but is viewed as standing in accord with, rather than in contrast to, an interpretive tradition. In the other view, tradition is more than the ongoing churchly interpretation of the biblical revelation-it contains truths handed down orally in the church from the time of Christ and the apostles, but never placed in written form. In particular, this view of tradition assumed that the apostles had written down all of the teachings of Jesus belonging to his earhly ministry between baptism and cricufixion but had not reported fully Jesus’ teachings between the resurrection and ascension. “In the first case,” Oberman writes, “tradition was seen as the instrumental vehicle of Scripture which brings the contents of Holy Scripture to life in constant dialogue between the doctors of Scripture and the Church; in the second case, tradition was seen as the authoritative vehicle of divine truth, embedded in Scripture but overflowing in extrascriptural apostolic tradition handed down through episcopal succession” (Muller, pp. 52-53, quoting Heiko Oberman, “Scripture and Tradition: Introduction,” pp. 54-55).
I want to point out one further qualification that must be kept in mind here. The Protestant position can generally be identified with position 1 (though with the qualification below), and the Catholic position with position 2. The qualification that needs to be made here is that Protestantism sees itself in continuity with tradition, but recognizes that tradition may err. This is usually misinterpreted by the Catholics as saying that Protestants throw off tradition altogether. This is, of course, not true. Just because we reject Roman Catholic traditions that they have invented out of thin air does not mean that we reject all tradition. Tradition has a subordinate, ministerial position to Scripture, not an equal, magisterial position in relation to Scripture. Herein lies the difference between Protestants and Catholics on the issue of tradition. The problem Catholics have had in the past is that they see Protestants subordinating tradition to Scripture, and interpret that move as throwing off all non-individual authority. We can illustrate this very well by speaking about the confessions of the Reformed church. The Scripture is the “norming norm,” whereas the confessions are the “normed norm.” The confessions have more authority than the voice of a single individual, since, obviously, the principles that govern a group of people are not necessarily the same as those that govern individual people. However, the authority of confessions is not equal to the authority of Scripture. So, rather than having three equal sources of authority in Scripture, tradition, and pope, Protestants acknowledge one supreme authority in Scripture, and then subordinate, ministerial authority in confessions (which yet have greater authority than individual voices).