Our Gemara on Amud Aleph discusses the opinion of Shmuel that Babylonia is considered outside of Israel and a Get needs the messenger to attest to the signatures. Shmuel holds that though due to the constant traffic to and from the yeshivos in Israel to Bavel, there ought to be sufficient witnesses who could attest to the signatures on the Get, the Benei Yeshiva are engrossed in their studies and nonetheless would not recognize signatures.
There is a known archetype or pattern of human behavior where certain scholarly types who get lost in their thoughts and are unable to tend to practical affairs. In popular culture this archetype is known as the Absent Minded Professor. In both secular and Jewish history, we find gifted individuals who also had difficulty focusing on the present. It is said of the ancient philosopher Thales, that walked at night with his eyes focused on the heavens and, as a result, fell down a well. Similarly, it is said of Einstein that he once walked into a store, completely befuddled, and said, “I am the world famous Albert Einstein, can you help me find my way home?“ There are recent Torah scholars from past and recent present who were also known for being so focused that they might not notice their physical pain or even family members, such as Rav Elyashiv (https://seforimblog.com/2014/01/the-vilna-gaon-part-2-review-of-eliyahu/ ) . Relevant to Shavuos and this topic, we find Rava behaving in a similar way, which was mocked by a heretic (Shabbos 88a):
הָהוּא מִינָא דְּחַזְיֵיהּ לְרָבָא דְּקָא מְעַיֵּין בִּשְׁמַעְתָּא, וְיָתְבָה אֶצְבְּעָתָא דִידֵיהּ תּוּתֵי כַּרְעָא וְקָא מָיֵיץ בְּהוּ, וְקָא מַבְּעָן אֶצְבְּעָתֵיהּ דְּמָא. אֲמַר לֵיהּ: עַמָּא פְּזִיזָא, דְּקַדְּמִיתוּ פּוּמַּיְיכוּ לְאוּדְנַיְיכוּ, אַכַּתִּי בְּפַחְזוּתַיְיכוּ קָיְימִיתוּ. בְּרֵישָׁא אִיבַּעְיָא לְכוּ לְמִשְׁמַע, אִי מָצִיתוּ — קַבְּלִיתוּ, וְאִי לָא — לָא קַבְּלִיתוּ. אֲמַר לֵיהּ: אֲנַן דְּסָגֵינַן בִּשְׁלִימוּתָא כְּתִיב בַּן: ״תֻּמַּת יְשָׁרִים תַּנְחֵם״, הָנָךְ אִינָשֵׁי דְּסָגַן בַּעֲלִילוּתָא כְּתִיב בְּהוּ: ״וְסֶלֶף בּוֹגְדִים יְשָׁדֵּם״.
The Gemara relates that a heretic saw that Rava was immersed in studying halakha, and his fingers were beneath his leg and he was squeezing them, and his fingers were spurting blood. Rava did not notice that he was bleeding because he was engrossed in study. The heretic said to Rava: You impulsive nation, who accorded precedence to your mouths over your ears. You still bear your impulsiveness, as you act without thinking. You should listen first. Then, if you are capable of fulfilling the commands, accept them. And if not, do not accept them. He said to him: About us, who proceed wholeheartedly and with integrity, it is written: “The integrity of the upright will guide them” (Proverbs 11:3), whereas about those people who walk in deceit, it is written at the end of the same verse: “And the perverseness of the faithless will destroy them.”
I should also say that there are two types, and it’s unclear to which kind Rava belongs. There is the Absent Minded Professor, as we described earlier, who is so lost in thought, that ordinary every day matters neglected. Then there is a person who has such a strong spiritual yearnings that he withdraws from this world. There is a deep yearning within the human soul, to reattach to its original source in God. Like a drop of water is joined back to the sea, when a human being encounters the godly and the spiritual, there is a magnetic tug to let go of physical bonds. Arvei Nachal Bereishis (5) writes about this experience:
There is no limit to love for God, and it is even possible that from a person’s great yearnings to attach to God, he will die. This is what it means when it states in VaYikra (16:1) by the sons of Aaron, “When they drew near to Hashem and subsequently died.”… the Sages (Berachos 63b) said that “Knowledge of Torah is not firmly established, except for those who kill themselves over it.” What they mean is that a person can study Torah with such intensity that he loses perception of physical functions such as what occurred to Rava (in the Gemara above). This is a kind of death, because the person becomes detached from physical concerns and sensations. When a person remains in this state, the physical functions begin to draw their life force from spiritual energy, and no longer require the same physical energies.
(I assume this is can explain how Moshe was able to go 40 days and 40 nights without eating.)
While we are on the topic of sages who became so distracted by their Torah study, we find a clever Ben Yehoyada who uses this to answer a question on a famous story described in Yoma (35b):
אָמְרוּ עָלָיו עַל הִלֵּל הַזָּקֵן שֶׁבְּכׇל יוֹם וָיוֹם הָיָה עוֹשֶׂה וּמִשְׂתַּכֵּר בִּטְרַפָּעִיק, חֶצְיוֹ הָיָה נוֹתֵן לְשׁוֹמֵר בֵּית הַמִּדְרָשׁ, וְחֶצְיוֹ לְפַרְנָסָתוֹ וּלְפַרְנָסַת אַנְשֵׁי בֵיתוֹ. פַּעַם אַחַת לֹא מָצָא לְהִשְׂתַּכֵּר, וְלֹא הִנִּיחוֹ שׁוֹמֵר בֵּית הַמִּדְרָשׁ לְהִכָּנֵס. עָלָה וְנִתְלָה וְיָשַׁב עַל פִּי אֲרוּבָּה כְּדֵי שֶׁיִּשְׁמַע דִּבְרֵי אֱלֹהִים חַיִּים מִפִּי שְׁמַעְיָה וְאַבְטַלְיוֹן.
They said about Hillel the Elder that each and every day he would work and earn a half-dinar, half of which he would give to the guard of the study hall and half of which he spent for his sustenance and the sustenance of the members of his family. One time he did not find employment to earn a wage, and the guard of the study hall did not allow him to enter. He ascended to the roof, suspended himself, and sat at the edge of the skylight in order to hear the words of the Torah of the living God from the mouths of Shemaya and Avtalyon, the spiritual leaders of that generation.
אָמְרוּ: אוֹתוֹ הַיּוֹם עֶרֶב שַׁבָּת הָיָה, וּתְקוּפַת טֵבֵת הָיְתָה, וְיָרַד עָלָיו שֶׁלֶג מִן הַשָּׁמַיִם. כְּשֶׁעָלָה עַמּוּד הַשַּׁחַר אָמַר לוֹ שְׁמַעְיָה לְאַבְטַלְיוֹן: אַבְטַלְיוֹן אָחִי, בְּכׇל יוֹם הַבַּיִת מֵאִיר וְהַיּוֹם אָפֵל, שֶׁמָּא יוֹם הַמְעוּנָּן הוּא? הֵצִיצוּ עֵינֵיהֶן וְרָאוּ דְּמוּת אָדָם בַּאֲרוּבָּה. עָלוּ וּמָצְאוּ עָלָיו רוּם שָׁלֹשׁ אַמּוֹת שֶׁלֶג. פֵּרְקוּהוּ, וְהִרְחִיצוּהוּ וְסָכוּהוּ, וְהוֹשִׁיבוּהוּ כְּנֶגֶד הַמְּדוּרָה. אָמְרוּ: רָאוּי זֶה לְחַלֵּל עָלָיו אֶת הַשַּׁבָּת.
The Sages continued and said: That day was Shabbat eve and it was the winter season of Tevet, and snow fell upon him from the sky. When it was dawn, Shemaya said to Avtalyon: Avtalyon, my brother, every day at this hour the study hall is already bright from the sunlight streaming through the skylight, and today it is dark; is it perhaps a cloudy day? They focused their eyes and saw the image of a man in the skylight. They ascended and found him covered with snow three cubits high. They extricated him from the snow, and they washed him and smeared oil on him, and they sat him opposite the bonfire to warm him. They said: This man is worthy for us to desecrate Shabbat for him. Saving a life overrides Shabbat in any case; however, this great man is especially deserving. Clearly, poverty is no excuse for the failure to attempt to study Torah.
Ben Yehoyada asks, how would it have been permitted for Hillel to put himself in danger? It must be that it was not originally cold outside, and the weather suddenly changed. At that point, Hillel was so engrossed in his studies that he did not notice, even as his vital signs were fading and he was slowly freezing to death. There are hints in the story to the fact that the weather suddenly changed. There is a line about “snow from heaven fell upon Hillel. Well, of course, the snow from heaven fell upon him”, but where else would it come from? The point is that it was divinely ordained to suddenly have a change of weather; for it to snow to bring out Hillel‘s greatness. Also, if it was a typically snowy day, the rabbis would not notice if the skylight became darkened, anyway, as they would expect an accumulation of snow. Shmaya and Avtalyon remarked on the sudden covering of the skylight as an unusual occurrence.
Of course, just as the earlier referenced sons of Aaron became flooded and overwhelmed by spirituality when they weren’t fully ready to tolerate it with unfortunate consequences, so too there are individuals who are not yet fully developed in character to bear this kind of focus. Without the right psychological and emotional development, it can lead to alienation from family and friends, as well as the possibility of burning out by underestimating the need for self-care and tending of the body.