Rashi vs Rabbeinu Tam

The Tiff Over Two Tefillin

Is wearing both Rashi and Rabbeinu Tam tefillin a fulfillment of mitzvos—or a violation of baal toseif? This article explores the halachic logic behind wearing two pairs of tefillin, the Chofetz Chaim’s resolution, and how similar issues arise in mezuzah placement. Along the way, we examine intent, appearance of transgression, hybrid fulfillments, and how poskim deal with irreconcilable disputes in practical halacha.