To defend Rebbi Yosi's view, a beraisa is brought in regarding erasing shem Hash-m on one's skin in a mikveh, also using concept of gerama. How is it possible to compare these two scenarios, notwithstanding gerama is employed in both? In the kivuy case, the person's intent IS to put out the fire! In the mikveh case, his intent is to perform a mitzva!
Daniel Ettedgui, Boca Raton, USA
(a) The point is that, on Shabbos, if one does something through Grama, mid'Oraisa this is simply not considered as doing work and consequently it does not make a difference what one's intention is. The Gemara derives from the verse, "You shall not do any Melachah," that any "doing" is forbidden by the Torah, but if one merely causes it, this is permitted. The Torah does not want us to work on Shabbos. If we do not do it directly, the Torah does not consider this as working. Therefore, even though one intends that the water should extinguish the fire, this is permitted because the person did not extinguish the fire, but rather the water did so as an inderect result of the person's actions.
(b) Possibly, just for the sake of illustration, we could compare this to one who thinks about doing Melachah. The Torah does not prohibit one from thinking about his affairs on Shabbos as long as he is resting from Melachah in practice. (The Shulchan Aruch OC 306:8 writes that one receives the maximum pleasure from Shabbos when he does not think about his business at all. However, this could be described as praiseworthy advice, as there is no Torah prohibition involved merely in thinking about doing Melachah.) Similarly, performing Melachah merely by Grama is not forbidden by the Torah because one is not doing Melachah actively. Therefore, one is permitted to place the utensils which are full of water in front of the fire, even though his intention is that the water will put out the fire. It is permitted since he is not actively doing any Melachah.
Kol Tuv,
Dovid Bloom