Takanah: when the sages establish something new תקנה
The law of the Torah is not changed. But when life breaks against the law, the sages set an enactment beside it—and it holds not by force but because the community accepts it.
A takanah is an enactment introducing something new; unlike a gezerah, which forbids the permitted as a fence.
The model: the prozbul. The Torah commands the release of debts in the seventh year. Hillel saw that before the Sabbatical year people had stopped lending: "This is one of the matters that Hillel the Elder instituted, because he saw that the people were refraining from lending to one another" (Gittin 36a). The prozbul hands the debt over to the court, and the court collects. The law of the Torah is not annulled—what is changed is whose the debt is.
How this is possible. The Gemara takes the question apart and does not pretend there is none. Abaye's answer: in our time the Sabbatical release is itself established by the sages and not by the Torah—and therefore the sages may amend their own.
What holds a takanah up. Not authority but acceptance. An enactment the community has not accepted does not bind; one accepted binds for centuries. Hence in Jewish law enactments are named by place and time: the takanot of Shum (Speyer, Worms, Mainz), the takanot of Fez, the ban of Rabbeinu Gershom.
Where it is visible on the timeline. Hillel's prozbul, Rabbeinu Gershom's ban on polygamy, the enactments of the exiles in Fez, the Council of Four Lands. Each time it is not a new law in place of the Torah but an amendment to how one lives with it in a changed world.
On the timeline
Related
Sources
Chazal: Mishnah, Talmud, midrash, Zohar
- Gittin 36a — Hillel's prozbul and the analysis of how the sages may establish it
- Mishnah, Sheviit 10:3–4 — the prozbul in the Mishnah itself: what it is and how it is written
Basis: Talmud and midrash.