Hussar
Legend
D&D rules, as written don't logically follow this principle. If magic has no sentience then anyone can invoke it - hence in the world view above there cannot logically be a split between the spells of wizards and clerics. Game balance demands otherwise though - so we arrive at a quandary.
My own setting divides magic into five distinct types. Study of any given type of magic precludes study of the others. No given character can master all spells.
Also, the above world type perforce bans spells that do put spell casters into direct contact with outer powers (or can do so) such as contact other plane, planar ally, and gate.
Not really though. Game balance does not demand that magic be split between divine and arcane. After all, lots and lots of spells cross the boundary anyway, so, there's never really been a hard and fast split between the two. Never minding something like a 3e bard which casts cleric spells as arcane. Or a 2e Specialty Priest, many of whom gain Magic User list spells as part of their own spell list.
Cleric and wizards cast different spells, sure, but, there's no real game balance reason we can't include them both under the same umbrella.