The discussion of trapping an animal on Shabbat leads to a discussion of the animal hide parchment used for writing phylacteries. Among the topics presented is the following:
And this question was asked by a Boethusian to Rabbi Yehoshua HaGarsi:
From where is it derived that one may not write phylacteries on the hide of a non-kosher animal?
He said to him, it is as it is written: “So that God’s Torah will be in your mouth.” The Rabbis derived that one may write the passages only on an item that is permitted to be placed in one’s mouth, i.e., eaten.
He said to him: If that is so, on the skin of neveilot and tereifot coming from kosher animals, one should not write phylacteries, as they may not be eaten.
He said to him: I will tell you a parable. To what is this similar? To two people who were sentenced to death by the king. One was killed by the king himself, and one was killed by an executioner [ispaklitor]. Which one is more praiseworthy? You must say: The one that the king himself killed. Therefore, an animal that died at the hands of Heaven and not by a human action is superior.
He said to him: If so, then the neveilot and tereifot should be eaten, as they were killed by the king.
He said to him: The Torah said: “Do not eat any neveila” (Devarim 14:21) and you say they should be eaten? A Torah decree determines that they may not be eaten, but that does not mean they are inferior. The Boethusian said to him: Well put [kalos].
The Boethusians were a sect similar to the Sadducees, who rejected the authority and customs of the Sages. According to the Talmud, this sect was named after its founder, Boethus. The exact differences between this sect and the Sadducees are unknown because the terms are used interchangeably in some sources. Apparently, the Boethusians followed the Written Torah based on their own interpretations, e.g., they always celebrated the festival of Shavuot on Sunday. Nevertheless, they may have been similar to the Pharisees in their basic outlook.