Kenneth B. Haase
MIT Media Lab., 20 Ames St., Rm. E15-482, Cambridge, MA 02139-4307
A ``rational reconstruction'' of the jazz improvisation system implemented in [David Levitt, ``A Melody Description System for Jazz Improvization,'' MIT S.M. thesis (1981)] will be discussed. A rational reconstruction is a reimplementation of a computer program in a way which clearly reveals its basic mechanisms and the fundamental issues it addresses. Levitt's program did melodic improvisation from an initial chord progression, based on a collection of heuristics operating over a simple constraint representation. Its rational reconstruction reveals a number of basic issues in computational aesthetics: The use of constraints to model aesthetic choice; the use of representation to encode stylistic background; and the tension between randomness and structure in creative process.