Our Gemara on Amud Aleph discusses a particular sage, Rav Chana bar Chanilai who was so involved in his studies, that Rav Huna told him his meat was more prone to being under the ban of unknown meat because he would not pay attention to where it was placed and therefore may have been switched with Non Kosher meat. In essence, with all due kavod, Rav Chana bar Chanilai was being called absent-minded.
The absent-minded processor archetype is indeed an old one, stemming back to ancient times. In Plato’s Theaetetus, written around 400 BCE, Socrates relates a story that the mathematician Thales was so intent upon watching the stars that he failed to watch where he was walking, and fell into a well. (Thales lived around 600 BCE. By contrast, Rav Chana bar Chanilai lived around 900 years later, in 300 CE.) Presumably, we are dealing with a fellow who was so preoccupied with his intense deliberations, thoughts, theories and calculations that he failed to notice basic hazards, and his actions. Another Amora, Rava, also was observed in an absent minded moment, to have been so intensely focused on his studies, that he didn’t notice that he was sitting on his fingers, crushing them to the point of bleeding (Shabbos 88a).
In actuality, there are two kinds of absent-mindedness. One is the above character, who is kind of endearing, and clearly engaged in life. If anything, he is too intensely engaged and focused to the point of missing out on basic mundane concerns. This kind of absent mindedness is treatable through mindfulness and meditation, as well as using apps and other cues to act as reminders. All in all, a somewhat annoying but mostly benign condition.
However, there is a darker form of absent mindedness such as those who disassociate and blank out. Persons such as this are not necessarily engaged in anything. They more or less daydream or just shut down. Barring organic causes, that form of disassociation often comes from prior traumatic and Abusive experiences. There are children who are misdiagnosed with ADD because they don’t pay attention. However, the root cause is not ADD. It is trauma anxiety leading to high distractibility and difficulty focusing. Persons such as this should be assessed for trauma and Dissociative Disorder, because there are significant quality of life and quality of relationship issues at stake.
Translations Courtesy of Sefaria, (except when, sometimes, I disagree with the translation .)