What is still mystifying is how a bracha on shabbos candles not provided in the Gemara could be made for an ostensible mitzvah (as even reported by R. Amram Gaon, the Rosh, etc.). Chazal gave a nusach in the gemara for chanukah candles, and could have equally done so for shabbos candles. This is not explained in the sources for some reason, nor is the source for the bracha itself (as is the case of a number of other brachas).
With regard to Yomtov, until modern times the only source of light was candles of some kind, so lighting some for Yomtov was not a chiddush. But in our day it would seem to be definitely unnecessary, and certainly not with a bracha, since as the source points out there was no takkana for candles on Yomtov, and it would be a kal vachomer for the second day of yomtov, which R. Chaim of Brisk and others have pointed out is only a minhag bizmanenu.
Finally, the suggestion about using the lights is only according to a shita that holds that electricity is fire, but not otherwise. Indeed, there is no consensus at all as to what makes electricity prohibited on shabbos as a melacha at all, and it was R. Shlomo Zalman Auerbach who explained that really there is no melacha involved in electricity (he explained how it is not fire, boneh, molid or makeh bepatish). He considered abstaining from electricity to be a minhag.
David Goldman, USA
I will attempt to clear up some of the confusion and summarize points that I have been making in recent answers.
1) Many major Mefarshim cite a source for the Berachah on Shabbos and Yom Tov candles from the final chapter of the Yerushalmi Berachos. Possibly, the most accesible of these Mefarshim for us is the commentary of the Gra on Shulchan Aruch (OC 263:5). The Shulchan Aruch writes that when one lights the Shabbos candles, one says a Berachah "l'Hadlik Ner Shel Shabbos." The Gra writes that the source for this Berachah is the aforementioned Yerushalmi.
If we now look up one of the major Rishonim, the Ra'avyah, we find that he opens Hilchos Yom Tov (#712) by writing: "The Yerushalmi in the fourth chapter of Maseches Beitzah [says]: 'When lighting the Yom Tov candles one must say the Berachah... l'Hadlik Ner Shel Yom Tov.'" The Ra'avyah also cites the last chapter of Yerushalmi Berachos, as mentioned above in the name of the Gra, as a source for the Berachah for Yom Tov lights. In addition, the Ra'avyah in Maseches Shabbos #199 cites sources for lighting the Shabbos and Yom Tov candles from the Yerushalmi Berachos.
See note 10 to the Ra'avyah, Shabbos #199, who cites a number of Rishonim who mention the Yerushalmi as the source for the Berachah.
We do not have the above text in our editions of the Yerushalmi. However, it is not unusual to find that the Rishonim possessed a different text in the Yerushalmi than our text.
The Berachah on Shabbos candles therefore has a source from Chazal, namely from the Talmud Yerushalmi.
2) Tosfos to Shabbos 25b (DH Chovah) and the Rosh there do not cite the Yerushalmi but they do cite Rav Amram Ga'on, a very early source, who lived not long after the completion of the Gemara. It is well-known that the Rishonim often write that all the words of the Ge'onim are "Divrei Kabalah." Kabalah means "receiving"; the Ge'onim received the traditions of Torah from the Sages of the Gemara, because the Ge'onim lived not long after the Gemara. Therefore, Tosfos and the Rosh assume that Rav Amram possesed a tradition from Chazal that one says a Berachah on lighting Shabbos candles.
3) We have also seen the Taz (Orach Chayim 46:7) who justifies saying ha'Nosen la'Ya'ef Ko'ach every morning, even though this Berachah is not mentioned in the Gemara. The Taz writes that since there is a custom to say this Berachah, one should not abolish this custom, even though it is not stated explicitly in the Gemara, because it may be that the Ge'onim who instituted this Berachah had a tradition from the time of the Gemara that one should say it. We also saw that the Bach (Orach Chayim 46) writes that the text of the Gemara of the Semag included the Berachah of ha'Nosen la'Ya'ef Ko'ach.
4) In short, even though we do not find the Berachah on Shabbos or Yom Tov candles in our text of the Talmud Bavli, nevertheless many Rishonim possessed such a text in the Yerushalmi. Alternatively, they knew that Rav Amram Ga'on possessed such a text, so it is reasonable to assume that he received this Berachah from Chazal.
5) The Gemara in Beitzah 4b calls the second day of Yom Tov a Minhag, but Maseches Sofrim (14:18) states that "custom abolishes Halachah." Therefore, the well-established custom of second day Yom Tov is powerful enough to enable us to make a Berachah on the candles of second day Yom Tov.
1) Regarding the Yerushalmi the point was that if something was cited in the Yerushalmi that we do not have, and there is no statement there about a gezeyra from Chazal, and we have no support for it in the Bavli at all, we would not consider it to be binding. Indeed, some Jews, including Yemenites, made no bracha on yomtov candles.
2) Presumably the same source that mentions a gezeyra for lighting shabbos candles in the Bavli for shalom bayis could have also added a few word of a bracha for a binding bracha.
3) About the Rosh and your alternative explanation to resolve the contradiction. I had suggested that the statement about the obligation to light the candles may have been an misattributed addition into a manuscript. Indeed, we know about statements attributed to Rashi and others that are not actually from Rashi.
Finally, I thought that the many brachas we have that are shevach (in the siddur and davvening) are the ones that did not have to be mentioned in the Talmud and could have been derived from Maseches Sofrim, the Gaonim or even later but are still optional, but brachas required for a mitzvah ("asher kideshanu....vetsivanu....") are the ones that need to be from the Talmud. But the person you spoke with seems to have it the other way around because the Rosh in Bechoros is talking about only making brachas that ARE in the Talmud.
1) (a) The fact that a number of Rishonim do possess the text in the Yerushalmi that one says a Berachah on Shabbos candles and Yom Tov candles is a stronger proof for us than the fact that our Yerushalmi does not possess this text and that our Bavli also does not possess the text. The Yerushalmi is no less reliable than the Bavli, unless the Bavli explicitly contradicts the Yerushalmi (in which case we say that since the Bavli was compiled later than the Yerushalmi, it must be that the Bavli is deliberately arguing with the Yerushalmi).
(b) I would say that the fact that Yemenite Jews do not make a Berachah on Yom Tov candles is actually a proof that they do make a Berachah on Shabbos candles. There is a side reason why they do not make a Berachah on Yom Tov candles -- namely, that since it is possible to light them on Yom Tov, no special institution was made that one must light them before Yom Tov starts. Since there is no fixed time for lighting the Yom Tov candles, they argue that you do not make a Berachah. However, the fact that Yemenites light Shabbos candles with a Berachah proves that they believe this is an obligation according to the Rambam.
2) Again, the fact that the Yerushalmi does say it is a stronger proof for us than the fact that the Bavli does not say it. Sometimes one can infer from the silence of a particular source, but it is much more powerful if one has a different source saying something explicit.
3) The Gemara in Shabbos 25b states explicilty that it is an obligation to light Shabbos candles, and this cannot be a manuscript error.
I'm sorry. Regarding your 3), maybe I wasn't clear. I meant that the contradiction in the Rosh about the bracha on shabbos candles could still possibly be a misattribution in a manuscript because the contradiction is so glaring. The Bavli could certainly have added a few more words for an explicit bracha "asher kideshanu".
In a related matter, I am not sure why one would consider something binding that is found in Meseches Sofrim as if it were equivalent to the gemara, which it isn't since it was produced after the Talmud was sealed (similar to the concept of "divrei kabbalah").
I assume that you agree that the Rosh at the end of Maseches Bechoros -- who says that we have no Berachah that is not mentioned in the Mishnah, Tosefta, or Gemara -- remains. What you are suggesting is that we make an emendation in the Rosh in Shabbos 2:18. If so, I think we would have to erase the entire piece, from where he cites Tosfos that some say one should not say a Berachah on the Shabbos candles, until the beginning of the Rosh on Shabbos 26a. This is quite a lot to have to erase. Usually, when the Acharonim make emendation, they change a few letters, or at most 2 or 3 words, but not one third of a page. The Rosh is a Sefer that has been very thoroughly studied by Klal Yisrael for hundreds of years. If there is a contradiction between the Rosh in Shabbos and the Rosh in Bechoros, why did nobody notice it?