liv | Technical rabbinic text question (Reply)

So does anyone know anything about the prohibition on writing down halachot / writing down the oral Torah? Behind the cut is deeply technical stuff, and I'm sufficiently confused about it that I don't think I can explain if you can't follow my description. But there's quite a few people reading this who are likely to know more about the topic than I do, so I'm posting about it to ask for help.

cjwatson tracked some of it down to Temura 14a-b, which is a tractate I hadn't even heard of (I assumed at first it was a typo for Terumah). We tried to learn it (well, from the Steinsaltz translation, it's far beyond my Gemara skills to do it properly). It's a very complicated sugya about technicalities of sacrifices, except buried in middle there's this really interesting bit about what can and can't be written down.

The bit we're most excited to understand is this:

Rather, Rav Yosef said: The meal offering accompanying the libations may be sacrificed at night, and therefore one should delete from this baraita the item: 'Meal offering that accompanies the libations', from the list of the offerings that may not be brought at night.

When Rav Dimi ascended from Babylonia to Eretz Yisrael, he found Rav Yirmeya sitting and saying in the name of Rabbi Yehoshua ben Levi: From where is it derived that libations that come with an animal offering may be sacrificed only in the day? The verse states: “These you shall offer to the Lord in your appointed seasons, beside your vows, and your voluntary offerings, and your burnt offerings, and your meal offerings, and your libations, and your peace offerings” (Numbers 29:39). The juxtaposition of these two items teaches that just as peace offerings may be sacrificed only during the day, so too libations may be sacrificed only during the day.

Rav Dimi said to Rav Yirmeya: If I find someone who can write this opinion in a letter, I will send it to Rav Yosef in Babylonia, and in light of this ruling he will not delete the phrase: The meal offering that accompanies the libations, from the baraita. [...]

The Gemara raises a difficulty with regard to Rav Dimi’s suggestion to write this opinion in a letter. And even if he had someone to write a letter for him, would it have been possible to send it? But didn’t Rabbi Abba, son of Rabbi Ḥiyya bar Abba, say that Rabbi Yoḥanan said: Those who write halakhot are considered like those who burn the Torah, and one who learns from written halakhot does not receive the reward of studying Torah. Evidently, it is prohibited to send halakhot in letters.

Before resolving the difficulty, the Gemara further discusses the prohibition of writing down the Torah: Rabbi Yehuda bar Naḥmani, the disseminator for Reish Lakish, expounded as follows: One verse says: “Write you these words,” and one verse says, i.e., it states later in that same verse: “For by the mouth of these words” (Exodus 34:27). These phrases serve to say to you: Words that were taught orally you may not recite in writing, and words that are written you may not recite orally, i.e., by heart.

And furthermore, the school of Rabbi Yishmael taught: The word “these” in the command “write you these words” serves to emphasize that these words, i.e., those recorded in the Written Law, you may write, but you may not write halakhot, i.e., the mishnayot and the rest of the Oral Law.

They said in response to the question of how Rav Dimi could propose writing down the halakha in a letter: Perhaps with regard to a new matter it is different, i.e., it might be permitted to write down new material so that it not be forgotten. One proof for this suggestion is that Rabbi Yoḥanan and Reish Lakish would read from a scroll of aggada, containing the words of the Sages, on Shabbat. And they did so because they taught as follows: Since one cannot remember the Oral Law without writing it down, it is permitted to violate the halakha, as derived from the verse: “It is time to work for the Lord; they have made void your Torah” (Psalms 119:126). They said it is better to uproot a single halakha of the Torah, i.e., the prohibition of writing down the Oral Torah, and thereby ensure that the Torah is not forgotten from the Jewish people entirely.

I have a number of questions about this:

What's going on with the relationship between Babylonia and Palestine at this point?

Is the discussion implying that they aren't sure of the fidelity of transmission of baraitot?

Is writing a letter explaining a point of interpretation really the same as writing down halachot?

I have just been learning that the Rambam invented the modern conception of Torah min haShamayim, that is the idea that God directly dictated the content of all the Oral Torah to Moses on Sinai. According to my teacher R' Mark Solomon, at the time of the Talmud the mainstream view was that the Oral Torah came from God's revelation in the more narrow sense that God gave the rabbis the ability and right to interpret the written Torah. What's the conception of revelation being discussed here?

The example from Exodus seems to completely contradict the conclusion about not writing down Torah transmitted orally, because God explicitly spoke the words to Moses, and explicitly commanded Moses to write down what God spoke! But maybe God speaking to Moses doesn't count, since that was the method by which we received what became the Written Torah anyway.

Is the Gemara implying that R' Yoḥanan and Reish Lakish derived halacha, or more specifically the basis to make an exception to halacha, from Psalms? That's not supposed to happen.

This whole discussion is in the Gemara because it got written down! So what on earth was the redactor thinking when they wrote down a big discussion about how it's forbidden to write down halachot?

How did we get from here to the post-Talmudic tradition of writing down all the things in all possible circumstances?

Does anyone know this Gemara? Or is there anyone with better Gemara skills than me who would be willing to help me sort it out? Further, does anyone know where we should be looking in the halachic material to work out how this prohibition on writing down the Oral Torah was developed?

Help?