Four beautiful women

תנו רבנן: ארבע נשים יפיפיות היו בעולם: שרה <ואביגיל רחב> [רחב ואביגיל] ואסתר. ולמאן דאמר אסתר ירקרוקת היתה, מפיק אסתר ומעייל ושתי

The rabbis teach: There have been four super-beautiful women in the world: Sarah, Avigayil, Rahav, and Esther. According to the opinion that Esther was sallow, [the list] would exclude Esther and include Vashti.
(Megillah 15a)

As you can see from the Hebrew, there is a difference of opinion as to how this teaching should be worded. The list of women, as it appears in normal gemaras, goes as following:

Sarah, Avigayil, Rahav, Esther.

But on the side of the page is a note saying צ"ל רחב אביגיל – "It should say Rahav, Avigayil”. Thus the order becomes:

Sarah, Rahav, Avigayil, Esther.

Usually this kind of “it should say” correction appears when there is a relatively obvious and inconsequential error (let us say “typo”) in our printed gemara. Out of respect for the text (and humility regarding the certainty of our conclusions) we do not actually correct the typo. But we add the correction note so people know how to learn the gemara correctly, and don't puzzle for hours over a cryptic phrase that wasn't intended to have a deep meaning.

In our case, though, it's not obvious what the error is. In this list of names, how do we know, and why does it matter what order the names are in?

Let us try to understand the case by first looking at the “corrected” list. Here, the order is Sarah, Rahav, Avigayil, Esther. That corresponds to the chronological order in which the four women lived. In the “uncorrected” list, the names are out of chronological order. Evidently, whoever wrote the “correction” assumed that the list must be chronological, and reordered it accordingly.

In my mind, that is a rather reasonable assumption. (After all, the list is already mostly chronological, and one would hardly expect the names to be ordered randomly.) But there's another possibility.

After listing the four women, the gemara mentions that according to some opinions, Esther was actually rather ugly. If so, then what happens to our list of four beautiful women? The number four is preserved by replacing Esther with Vashti. Then, the “uncorrected” list becomes:

Sarah, Avigayil, Rahav, Vashti.

That list is not in chronological order – but it does make perfect sense without any correction. The first two women in the list are Jewish, and the last two are not.

Now let us return to the “uncorrected” list involving Esther:

Sarah, Avigayil, Rahav, Esther.

Perhaps, the list was intentionally ordered this way. In and of itself, the list has no logical order. But whoever wrote it also wrote the part about Vashti. They knew that later on they'd substitute Vashti for Esther in the list, so they wrote it with the Jewish/non-Jewish listing of women in mind.