The Amish exist because of an argument about shunning. The Anabaptists of the Reformation had recovered the ban as the discipline of a voluntary church, and their 1632 Dordrecht Confession included avoidance of the expelled. But practice diverged: the Swiss Brethren congregations in the Emmental applied the ban at the communion table and left ordinary social life intact.
Jakob Ammann, an elder in Alsace, insisted from 1693 on the strict reading: the expelled must be avoided in eating and daily dealings, Meidung in full, alongside other rigors, more frequent communion, foot washing, plainness of dress and the untrimmed beard. His confrontation with the senior Swiss elder Hans Reist split the Brethren; Ammann, in the heat of it, excommunicated his opponents wholesale, and though he later, remarkably, excommunicated himself in penance for his harshness and sought reconciliation, the division held. Ammann's party became the Amish; the Reist party's descendants merged into the Mennonite stream. The genealogy explains the practice's weight. Strict Meidung is not an incidental severity; it is the founding conviction, the point on which the community judged that a church unwilling to make exclusion cost something could not keep its baptismal promises meaningful. Every subsequent Amish schism, and there have been many, has tended to run along the same seam, stricter and milder applications of the ban, the eighteenth-century quarrel replaying in each generation's terms.