Rabbenu Tam (c. 1100–1171)

Jacob ben Meir of Ramerupt, called Rabbenu Tam — Rashi's grandson, and the dominant legal mind of northern France in the generation after him. A Tosafist: the school whose method was to take the Talmud's own arguments apart and find the tension Rashi had smoothed over.

He is in this house for one disagreement. On the order of the four scrolls in the head-box he differed from his grandfather, and because neither position could be dislodged, both survived — so that a minority of the Jewish world has worn a second pair of tefillin every morning for eight hundred years in order to satisfy an argument between two men in one family.

Worth keeping for what it shows about how this tradition handles an unresolved question. It does not vote, and it does not split. It keeps both, marks which is which, and lets the practice carry the doubt around in public. This app does the same thing on every page where it says a dispute is live — and it did not invent the habit. ⚠ And see tef-qumran: the frequent claim that archaeology has since vindicated him is not supported.