This past Shabbos someone said over to me a particular sugia they were learning in Taharas and a maklokes Rishonim in a particular iyun. One Rishon was basing himself partially on a Tosefta and his understanding of it. Among the the Rishonim on the other side of the maklokes was those that brought a proof from Toras Cohanim (Sifra.) While we could obviously discuss and try and other stand other points of this maklokes we began thinking if there is any “klal” or general statement in regards to what’s stronger (in terms of halacha — not neccessarily practical halacha but more in the context of such a maklokes) a Tosefta or or drasha from Toras Cohanim. Similar questions have been asked in the past in regards to what’s stronger Bavli or Yerushalmi or a Tosefta or Yerushalmi.
Is there any klal in this?
To my knowledge there is no klal in regard to this.
However, the regular principles of different tana’im will apply, so that if Rabbi Akiva is quoted in one, and a different tana in the other, the halacha will follow Rabbi Akiva.
If both are stam, then the Sifra (Toras Kohanim) is Rabbi Yehudah and Tosefta is Rabbi Nechemya, between whom I don’t believe there is a halachic general principle (we know that Rabbi Yosi defers both of them).