As I noted in the previous post, I do not find the Karaite explanation of Lo Tevaaru Esh compelling at all, and indeed think it somewhat ridiculous. It is certainly an explanation on the level of peshat, but I don't think that this is the true meaning of the verse, even on the peshat level.
Why not? Well, אל יצא איש ממקומו ביום השביעי as interpreted most literally would keep Jews stuck in their homes on Shabbat. And לא תבערו אש בכל מושבותיכם ביום השבת as interpreted in this literal manner would keep those confined Jews huddled in the dark, and the cold, since they cannot have fire or light in their homes.
Yeshaya states וקראת לשבת עונג. But how is this Shabbos an Oneg, a delight, if one must stay huddled in the dark and cold all Shabbos?! This is no Oneg. This is the second-to-last of the 10 plagues Hashem inflicted on the Egyptians. In Shemot 10:
(We see a similar value in Megillat Esther, perek 8: לַיְּהוּדִים, הָיְתָה אוֹרָה וְשִׂמְחָה, וְשָׂשֹׂן, וִיקָר.)
Can you imagine that with these values, and this appreciation of the joy of light, that Hashem would impose this makka, once every seven days, on the Jews?
Now, stranger things have happened. And peshat in pesukim may well go in a different direction than we might anticipate. But that the results seem so at odds with the Biblical conception of joy vs. sadness should perhaps cause one to question whether that is indeed peshat. And that is what I meant in my earlier statement that I regard it as just a bit ridiculous.
How then are we to understand the pasuk, on the level of peshat? At this point, I am not going to advance the Rabbinic interpretation, much of which involves derash. (In fact, I wonder how much the discussion was hampered by the urge to not just disprove the Karaite position but also advance the Rabbinic position.) I do think peshat-based interpretations are available which can lead us fairly close to Chazal's practical ending position. But first, I would like to explore other possibilities.
I would put forth that on a peshat level the injuction of lo tevaaru esh is not an example of a melacha. Rather, it is something that often must be done in the course of other melachot. We have earlier that they should prepare that which they bring, and prohibitions on performing the cooking and baking on Shabbat. Another example would be metalwork, or glasswork, or firing clay pottery, or boiling dyes, and so on. Thus, the previous pasuk says that one should not perform melacha on Shabbat. And to reinforce that message, this pasuk says that one should not be burning these fires for the purpose of this forbidden labor on Shabbat.
Indeed, the most appropriate comparison may be to the laws of Pesach: שִׁבְעַת יָמִים, מַצּוֹת תֹּאכֵלוּ--אַךְ בַּיּוֹם הָרִאשׁוֹן, תַּשְׁבִּיתוּ שְּׂאֹר מִבָּתֵּיכֶם: כִּי כָּל-אֹכֵל חָמֵץ, וְנִכְרְתָה הַנֶּפֶשׁ הַהִוא מִיִּשְׂרָאֵל--מִיּוֹם הָרִאשֹׁן, עַד-יוֹם הַשְּׁבִעִי.
Seor is sourdough. People do not eat sourdough. They eat chametz, leavened bread. Sourdough is used by bakers for the purpose of making bread rise. This pasuk states that sourdough should be given a rest from your homes, because they should not be eating chametz, and so presumably there is no reason to use the sourdough. (Whether that means it must be removed, or just that it is resting and not in use may be an interesting peshat-level question.) Did you notice the word מִבָּתֵּיכֶם?
It seems more than plausible to me, then, that there is a similar intent by lo tevaaru. One should not be burning these big fires in one's home, because that would be for the purpose of engaging in the forbidden "melacha."
If so, was the intent of the pasuk that the Israelites should sit huddled in the dark and cold in their homes, like Egyptians undergoing the 9th plague? Certainly not. And so lamps were not intended, and fireplaces were not intended. It was an esh shel melacha that the Torah assur-ed.
Yet we Pharisees even have such flames in our homes. We eat hot food. Well, who says that at that point it is considered "cooking." And perhaps a difference can be made between active melacha and letting it be done, or letting the process continue.
Mind you, this is not the same as the traditional Rabbinic position. For example, if it is only a flame of melacha the Torah assur-ed, then why shouldn't someone light a lamp on Shabbos? I do think that there are further peshat-level interpretations one can make, even along the same lines as above, that would explain this as well. (E.g. extending from the injunction against active work might yield lo tevaaru as active lighting which often starts melacha, and then the prohibition could extend to all cases of the act of kindling; or since it is part of a melacha or two the act of lighting is considered a melacha.) But I think enough for now. What I have above is sufficient for this post. I don't know whether it is true, but it seems to me like a compelling peshat-level interpretation, and more compelling than certain others.
Note: Obviously not intended halacha lemaaseh.