What does it mean to “Heal”?

The etymology of the the word Heal, as posted in the online etymology dictionary reads as follows:

heal (v.) Look up heal at Dictionary.comOld English hælan “cure; save; make whole, sound and well,” from Proto-Germanic *hailjan (cognates: Old Saxon helian, Old Norse heila, Old Frisian hela, Dutch helen, German heilen, Gothic ga-hailjan “to heal, cure”), literally “to make whole,” from PIE *kailo- “whole” (see health). Intransitive sense from late 14c. Related: Healed; healing

It’s important to consider that many healing methodologies pit the person against their illness, which enforces duality: