Hilchot Shabbat 1:5-6 (Davar She’eino Mitkaven and Pesik Reisha)
11:23 pm
In this shiur, the Rambam explains the Halachic concepts of Davar She’eino Mitkaven (the performance of a permitted action which may or may not cause a prohibited action as a consequence)and Pesik Reisha (the performance of a permitted action which certainly will cause a prohibited action to occur).