According to Khelben Arunsun, what is the nature of magic?
Here's what the lore says, drawn directly from the indexed sources:
Khelben Arunsun > Khelben Arunsun Khelben "Blackstaff" Arunsun was the Lord Mage of Waterdeep, a masked Lord of Waterdeep, and powerful archmage. He resided in Blackstaff Tower until his death. One of the few spellcasters to become one of Mystra's Chosen, and the last survivor of House Maerdrym, Khelben was a serious, imposing wizard and a grim proponent of law and order.
Source: Khelben Arunsun
Magic > Magic Magic was the ability possessed by some individuals to manipulate the ambient energies of the world to produce desired results, or so most thought. In the Realms, arcane magic was commonly referred to as "the Art", while divine magic was referred to as "the Power". In addition to granting spellcasting abilities, magic was an influential force in the Realms. It served as the source of energy for enchanted items, allowed Faerûnians to travel across Toril and through the extra-planar cosmology and even shaped the physical landscape of the planet. The basic essence of magic was…
Source: Magic