Christian Smith points out that the Westminster Confession comes up with the notion that all theological truth can be proved from the Bible using syllogistic deduction - that was in 1646, or the decade after Descartes' Discourse on Method claimed in 1637 that all philosophical truth can be proved from the mind using syllogistic deduction.
What we have in sola Scriptura is a trendy solution, by 1640s standards, for the problem of ongoing doctrinal disputes - it has now hardened from a fashionable trend to an unexamined tradition.
Thanks for your informative post.
Your mention of the Westminster Confession reminds me that it, and other confessions, would not be necessary if the basics of Sola Scriptura held in practice. All would agree negating the need.
After recently going back to study the Reformers starting with Luther, it seems clear to me that Luther had an aha moment - and scripture opened up to him in a way that answered some nagging questions he had. He saw it fit so clearly, to him anyway, that he thought once proclaimed everyone would agree with his new view: “yep, that’s plainly what scripture says and means.”
It wasn’t long before he was proven wrong, the box was opened for all manner of competing exegesis. Thus came the need for the various confessions to unify reformer congregations around a set of the “plain meaning” of scripture.
The confessions became the new authority, the reformers’ magisterium. Today, even that organization has broken down and we have each his own confession.