Adiaphora is a term that has played an important role in Lutheran history but not much in our own, although perhaps it should. Adiaphora is originally a Greek word that has been translated in different ways depending on context. In Lutheran theology it has sometimes been rendered as “middle things,” things that are neither required nor forbidden.
To compress and badly distort the full story, after Luther’s death and Lutheran defeat in the Schmalkaldic War, Holy Roman Emperor Charles V was in a position to impose what he saw as a fair solution to achieve religious harmony, the Augsburg Interim, which would have required Lutheran congregations to accept the celebration of all the Catholic sacraments. Support for accepting the Interim among Lutherans was led by Phillip Melanchthon and others at Wittenberg. What the emperor was asking for, in their view, were mere adiaphora, things not of central importance about which the faithful could find opportunities for compromise.
Not so fast, said Matthias Flacius (“Illyricus,” as he was originally from Croatia). Flacius was a prominent voice among the party of the Gnesio-Lutherans (from another Greek word for “genuine” or “authentic”; sixteenth-century Lutherans had no qualms about branding dissenting co-religionists as crypto-Papists or outright Satanists). Flacius certainly believed that while there could be adiaphora in the church, he argued that real adiaphora must be chosen by the church rather than imposed from outside; must not be proclaimed as necessary for salvation; and must not sell ungodliness as righteousness. In one of his (exceedingly numerous) contributions to the polemic literature of his day, Flacius proposed the following rule for what constituted adiaphora.
All ceremonies and church practices, be they as neutral by nature as you wish, cease to be adiaphora when they are accompanied by coercion, vain belief that they are necessary or constitute worship, renunciation, offense, a clear opportunity for godlessness, and ultimately whatever in any way does not build up but rather destroys the church and is an affront to God.
Flacius is saying in effect that the history of the Reformation from 1517 to that moment had been (among other things) about eliminating empty ceremonies and other needless accretions; in that context, Flacius argued, there could be no merely neutral performance of the old sacraments. In his view, while the mass might consist only of words with no inherent significance in themselves, to celebrate mass in a Lutheran church in 1547 could only be seen as a rejection of one of Luther’s central teachings and thus a renunciation of the Reformation and the true gospel along with it.
While I’m more sympathetic with Charles V’s view of sacraments, I think Flacius was on to something about adiaphora. We invest words and images and objects with meaning through a communal process and in a context that includes both the church and the society in which it exists. We can’t say “It’s just a word” or “it’s just a picture” or “it’s just a piece of cloth” when the thing in question has already been elevated to a point of doctrinal significance or marker of group identity. There are certainly adiaphora in the church. But the point of the Restoration (among other things) is to be led by a living prophet, so that dismissing as mere adiophora things that the prophets regularly teach and emphasize has consequences that far outweigh the apparent significance of the thing itself.