Explain why phantom limb sensation is considered one of the best-known and most clearly understood examples of an organic hallucination.

Phantom limb differs from other organic hallucinations in having a specific and very well-documented mechanism related to altered nerve signalling after limb loss, which makes the causal link between the physical event, amputation or congenital absence, and the resulting perceptual experience unusually clear and well understood compared with other organic hallucinations, where the underlying physical cause may be present but the precise mechanism linking it to the specific hallucinated content is less well characterised. This clarity is part of why phantom limb is so often used as the illustrative example when explaining what distinguishes an organic hallucination from a hallucination occurring in a primary psychiatric illness.