Eruvin

Shvus and Shvus L'Shvus: Tosafos on Permitted Rabbinic Violations

Why does Tosafos permit shvus l'shvus (double rabbinic Shabbos violations) for milah but forbid single shvus violations? The shiur distinguishes two categories: single shvus as negative prohibitions preventing melacha, and shvus l'shvus as positive obligations preserving Shabbos sanctity. Since milah can override positive commandments even non-simultaneously, it permits shvus l'shvus but not the negative prohibitions of single shvus.