Paul Erlich (born 1972) is a guitarist and music theorist living near Boston, Massachusetts. He is known for his seminal role in developing the theory of regular temperaments, including being the first to define pajara temperament and its decatonic scales in 22edo.

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His definition of harmonic entropy, a refinement of a model by van Eck influenced by Ernst Terhardt, has received attention from music theorists such as Bill Sethares.

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