I am going to answer this question based on sources in Maseches Sanhedrin.

1) The Mishnah in Sanhedrin (66b) states that one is not liable for the sin of Na'arah ha'Me'urasah (Rashi explains that this means one is not liable for Sekilah) unless she is (a) a Na'arah (i.e., between 12 and 12 1/2 years old, and not yet a Bogeres of 12 1/2 years old), (b) a Besulah, and (c) an Arusah (i.e., betrothed but not yet Nesu'ah, married). If these three conditions are not fulfilled, the punishment is Chenek and not Sekilah. We learn from here that the Halachah is indeed that the Bogeres receives Chenek.

2) Now let us go to another Mishnah in Sanhedrin, this one on 49b. The Mishnah states that there are four different punishments given by Beis Din: Sekilah, Sereifah, Hereg, and Chenek. Rashi writes that the order of the punishments is intentional because Sekilah is the most severe and Chenek is the least severe. We learn from here that the punishment given to the Na'arah ha'Me'urasah is actually worse than the standard capital penalty.

3) Now we go to Sanhedrin 50a to see why the crime of the Arusah, who is only "betrothed" (to use an approximate translation) but not yet married is worse than that of the Nesu'ah who is fully married. Rashi (DH Al Korchach) explains that when someone does a bad thing, it has three repercussions: (a) it is a crime against Hash-m; (b) it is a crime and a disgrace to other people; (c) it

is a disgrace to the person himself who commited the transgression.

4) If we focus on reason (c) we can understand why the crime of the Arusah is worse than that of a Nesu'ah. The crime is that

she stained her honor. The Chidush here is that the honor of the Arusah is even greater than that of the Nesu'ah. Rashi writes

that the Nesu'ah has already been "stained." This cetainly does not mean that the Nesu'ah has done anything wrong merely by getting married. What Rashi means is that a woman who is already married is not quite as special as a new bride who has not actually been yet with her husband. Rashi explains this a little more in Sanhedrin 73b (DH v'Lo Nafish). He writes that the groom has a special affection for his Arusah bride who possesses an extra grace. If she is unfaithful, this is an extra strong disgrace. The stain to her honor is even greater than that of a Nesu'ah.

I will close here and next time will relate to why the Bogeres gets a different punishment.

Chag Kasher v'Same'ach,

Dovid Bloom

Here is a beautiful explanation that I saw about why the Bogeres receives a less severe punishment than the Na'arah, based partly on the ideas we saw above.

1) The Toras Chaim (one of the early Acharonim who lived not long after the Shulchan Aruch, who is sometimes even cited by the Shach) in

Sanhedrin 50b (DH Iy) cites Rashi (mentioned above) who says that the punishment for the Arusah is more severe than for the Nesu'ah, and then he writes that the Bogeres is less severe than the Na'arah for similar reasons. He cites the verse (Bamidbar 30:17), "bi'Ne'ureha Beis Aviha" -- "in her youth-hood in her father's house," from which we learn that a Na'arah is still considered to be in the father's house and included in his responsibility.

2) The difference between the Na'arah and the Bogeres is as follows. In those days, at the age of 12 1/2, the girl was considered already independent. We see this in the Gemara later (Kesuvos 46b), that even

though the Na'arah got married through Erusin, the father still may annul her vows (this is learned from the aforementioned verse, "bi'Ne'ureha Beis Aviha"), while the father may not annul the vows of the Bogeres even though she is only an Arusah. The Toras Chaim writes that for this reason if the Na'arah sins it is a greater disgrace for the father and the rest of her family because she is still a closer part of the family. This is why she gets Sekilah. In contrast, if the Bogeres sins, it is slightly less of a Bizayon for the family, because she is already an independent individual and not so closely associated with the family any more.

Kol Tuv,

Dovid Bloom

Here is a different explanation, this time from the Maharal of Prague, to explain why the punishment for an Arusah is different from the punishment for a Nesu'ah.

1) In Sefer Be'er ha'Golah, Be'er 6, DH v'Achar Kach, the Maharal explains why we find in many places in Chazal (and also in the Din of the Torah that the Arusah receives the most severe punishment) that the sin of a Na'arah ha'Me'urasah who was unfaithful is considered the worst sin of all. The Maharal writes that this is because a sin with the Arusah is a sin "in Kedushah" -- the Erusin of the Torah is considered the highest level of holiness. The Maharal then writes a rather surprising thing: if a woman is already married, this is no longer a state of Kidushin. Even though the original Kidushin has not gone away, she is no longer considered an Arusah, and this is why the punishment for the Arusah is worse than for the fully married woman.

2) I will try to explain this rather difficult concept with the help of what I saw in the other books of the Maharal, particularly in Netzach Yisrael (chapter 47, and note 11 in Rav Hartman's edition). The Gemara in Sanhedrin 59a cites the verse (Devarim 33:40) that we say with every young child once he is old enough to talk: "Moshe commanded us the Torah, the Morashah (inheritance) of the congregation of Yakov." The Gemara says that one should not read the word "Morashah" but read it "Me'urasah." The idea is that the Torah is the Arusah of the Jewish people. Klal Yisrael is married to the Torah, since the Torah is the holiest thing in the world.

3) Why, though, is the Torah compared to an Arusah and not to a Nesu'ah? The answer is that the relationship of an Arusah to her future husband is actually a more spiritual relationship than that of a Nesu'ah. A Nesu'ah is actually living with her husband and there is already a physical relationship. In contrast, the Arusah -- even though she is already strictly forbidden to everyone else in the world -- is nevertheless not yet physically together with her husband. This means that the link of the Arusah to her husband is totally spiritual, and this is why it is compared to Torah which is totally spiritual. This is why someone who violates this relationship receives the most severe punishment, even more severe than the Nesu'ah.

Kol Tuv,

Dovid Bloom

Chaim, it is not clear to me when you refer to the Tana Kama in our Sugya in Kesuvos 45 who exactly you are referring to, so my answer is not going to relate specifically to Kesuvos 45 but instead to the general concept of Tana Kama in Shas. Of course Tana Kama means literally the first Tana because it is the first opinion mentioned, but it is usually an anonymous opinon and this can be very important.

1) There is an important Rashi at the end of the second chapter of Bava Metzia (33b, DH b'Mai) who tells us about how Rebbi Yehudah ha'Nasi ("Rebbi") compiled the Mishnah. He tells us how, in the days of Rebbi, there were finally peaceful times which enabled Rebbi to gather together all the scholars and arrange the teachings they had received into the Mishnah. What is relevant to us is that Rashi writes that Rebbi wrote "Stam" -- i.e. anonymously -- in the Mishnah the opinions of individual scholars whom he maintained the Halachah followed, in order that the Halachah should be fixed according to these opinions.

2) We learn an important principle from here, which is possibly the opposite of what one might have thought. If an opinion is mentioned anonymously in the Mishnah it is likely that this is actually a sign that it is the most weighty opinion and that the Halachah follows it. I understand that the logic behind this is that if no author is mentioned, then this indicates that this is the standard accepted opinon, while if the name of the author is mentioned this suggests that this is only the opinion of an individual but was not accepted by others.

3) Usually, when we refer to the Tana Kama, we are referring to an anonymous opinion, but we now know that the reason no name was given is because this is most likely the most important opinon in the Sugya. If we have a majority of the Sages siding with a certain opinion, this may also very often be mentioned as an anonymous opinon, with the same reasoning applying, because we are thereby being informed that the Halachah follows this opinion because it is the majority opinion.

4) In Maseches Bechoros, in most of the standard editons of Shas, at the end of the Maseches is printed Hilchos Bechoros of the Maharit Algazi. In the 6th chapter, in #55, he gives us an important rule. He writes that, generally speaking, when the Tana Kama is mentioned, this is synonymous with the Rabanan who are the majority. He writes that it is obvious that unless the Gemara states explicilty that the Tana Kama is only the opinion of an individual, we can assume that the Tana Kama is the majority opinion.

5) Now we can summarize and arrive at some conclusions. The Tana Kama is the first opinion mentioned, and he is usually the same as the Rabanan, which is the majority opinion. The "Sages" and the "Rabbis" ("Chachamim" and "Rabanan") are usually the same.

6) According to the above, if the anonymous Mishnah is Rebbi Meir, and since we say that the Tana Kama is anonymous, then it is difficult to see how Rebbi Meir could disagree with the Tana Kama since he himself is the Tana Kama.

7) After writing all of the above, I should point out that these are general rules, but there are exceptions to every rule. However, I think that the above would hold true in the majority of cases.

Kol Tuv,

Dovid Bloom