But the more I [Jason Stellman] read and wrestled, the more I began to see that Geneva was not being “confused with” Saddleback at all; the two were just different sides of the same coin (or to be more precise with the metaphor, they were sister-cities in the same Protestant county). Readers of this site have no need for the arguments to be rehearsed here, so suffice it to say that, philosophically speaking, it became clear to me that Sola Scriptura could not provide a way to speak meaningfully about the necessary distinction between orthodoxy and heresy (or even between essentials and non-essentials) [From his mysteriously deleted post at Called to Communion]
Jason (539), you say that claims for the papacy are based on the Bible and history. So let’s say you’re living in Italy in 1390. You have a pope in Rome and one in Avignon (where seven legitimate popes had ministered for almost eight decades). So how does the Bible or history help you decide which pope to follow?
That’s a question better suited for a historian.
On the one hand Stellman says the papacy is necessary to be able to distinguish heresy from orthodoxy. On the other hand, Stellman says it’s unnecessary to be able to distinguish a true pope from an antipope. We can relegate that determination to the fallible judgment of church historians. (And for the record, even Catholic church historians admit that they can’t always say which claimant was the true claimant.)
That’s like saying it’s necessary to have an accurate ruler to make measurements, but unnecessary to know which ruler is accurate. The papacy is a necessity in the abstract, but the concrete question of knowing whether any particular claimant is the true successor to Peter is not necessary.