Where's the boundary between "natural" and "artificial"? If we're allowing processing in the definition of "natural" (e.g. extracting a chemical from a plant us

Where's the boundary between "natural" and "artificial"? If we're allowing processing in the definition of "natural" (e.g. extracting a chemical from a plant using a solvent) then everything is natural: it's all ultimately derived from something that naturally occurred on Earth.