There are other questions to consider. When we talk about inventing spells, the way it's usually visualised is a wizard spending months or years of research and experimentation in their tower, but what about spells for other classes?
- Are all Cleric and Paladin spells powers granted by their deity, or can individuals of these classes conceive for themselves new ways of channelling their divine connection?
- Do druids or rangers research new ways of interacting with nature?
- Can a bard compose a new spell in much the same way they'd compose a new melody?
- As a sorcerer grows in power, can they find new ways to channel their innate arcane powers that none have conceived of before?
- Do a warlock's specific spells derive entirely from their patron? Could they collaborate with their patron to find new ways to manifest their power?
And beyond that, what does the invention of a new spell mean for casters of other disciplines? Can a wizard learn a spell that was invented by a bard, or a druid come to understand a spell first mastered by a cleric? Or, having seen the spell in action, would they then need to research it themselves in order to create a version that was adapted to their discipline?