Q. If Rashi and Rabeinu Tam wore different sorts of Tefillin that means that they received different traditions from Sinai – so how can we be sure that any of the traditions about anything are accurate? [Shai aged 12]
A. The reason why there are two types of Tefillin is not because Rashi and Rabbenu Tam had different traditions of how the Tefillin should be made but they had different understandings of exactly what order the parshiot – passages should be placed in the Tefillin Shel Rosh. Most people follow the opinion of Rashi whilst some also have a second set of Tefillin that are in line with Rabbeinu Tam’s opinion.