Why was this taught here? Our Mishnah discusses a meal!

Rav Elyashiv (51b): Since they discuss one who says Havdalah on the Kos Shel Brachah, it was taught with this.

How could they argue about matters that are done every week, e.g. the order of Kidush and Havdalah? Did they not see how their fathers and Rebbeyim blessed?

Anaf Yosef: We hold that the order of Berachos is not Me'akev (12a). We find that they used to bless Ahavah Rabah without Yotzer Ohr (Tamid 5:1). Everyone chose his own order, until Beis Shamai and Beis Hillel fixed an order. We can say similarly about all such arguments.

Which tense is proper for this Berachah?

Rashi: It is good to use past tense, for we praise Hash-m for creating light in the six days of creation. It was created on Motza'ei Shabbos, like it says in Pesachim (54a). Beis Shamai hold that Borei is improper, for it implies something created constantly. Light was already created!

Etz Yosef: Rashi hints to the Yerushalmi, which challenges Beis Shamai from Borei Peri ha'Gafen. It answers that wine is renewed every year; fire is not. Rav Elyashiv - Birkas ha'Peros thanks Hash-m for creating now and renewing His goodness every day. The Berachah on fire is because He gave Da'as to Adam ha'Rishon to bring fire from potential to actualization. It is past tense, for fire was created earlier, just it was actualized. The Ramban says that Borei Me'orei ha'Esh is like the Berachah on the sun. One who sees it in the place where Hash-m [first] put it, he praises for what was done in Ma'ase Bereishis. Also here, on Motza'ei Shabbos we bless on fire created n Motza'ei Shabbos of the days of Bereishis.

If all agree about Bara, why do Beis Hillel say Borei?

Tosfos: They hold that it is better to use the expression found in a verse.

Daf Al ha'Daf citing the Ga'on from Tshabin: We said above (38a-b) that it is not good to bless 'Motzi', for one should teach a Chidush via his Berachos! On 50a, Rava told Rafram 'why get involved in arguments?' (You should follow R. Yishmael, for even R. Akiva agrees that ha'Mevorach is better!) (NOTE: i.e. it seems that Amora'im argue about whether one should teach a Chidush via his Berachos, or fulfill all opinions. Why did Tosfos not suggest that Beis Shamai and Beis Hillel argue about this? - PF)

Why did Rav Yosef bring three verses?

Rashi: They show that Beis Shamai must agree that 'Borei' can refer to things that were created.

How can Rav Yosef say that all agree about 'Bara' and 'Borei'? They argue about them!

Anaf Yosef citing the Vilna Gaon (Shenos Eliyahu): 'Bara' is only past tense; and 'Borei' is past and present. Both of them apply to fire, for Hash-m created the Yesod (element) of fire. The difference is, the Yesod is one color, and our fire has many colors. Rather, they argue about Me'or and Me'orei - do we bless on the Yesod, or on our fire. Beis Shamai bless on the Yesod, which is one color; they must say Bara, for it was created before. Beis Hillel say that we bless also on our fire, which has many colors, and it is constantly made anew. We say Borei, which applies to the creation of the Yesod.

What are the many lights in a fire?

Rashi: The flame is red, white and yellow.

Surely Beis Shamai agree that there are colors in a flame. Why do they bless in the singular?

Ha'Boneh: Hash-m is compared to fire - "Hash-m Elokecha Esh Ochelah." Hash-m is alone - we should not mention more than one light. Beis Hillel hold, even though He is the ultimate unity, we can say that there are in Him many lights that are not divided, like fire.