We begin our investigation of aesthetics by postulating a structurefor algorithms for criticizing or designing works of art. Thisstructure fixes both the basic components of criticism algorithmsand design algorithms and the relations of these components. Issuesin aesthetics are investigated in terms of the structure postulatedfor criticism algorithms and design algorithms.The main aesthetic concepts used in the postulated structure forboth criticism algorithms and design algorithms are description,interpretation, and evaluation. Each of these concepts is given aprecise definition in terms of the components of the algorithms.Description, interpretation, and evaluation also play a centralrole in more traditional investigations of aesthetics such as Beardsley's.Beardsley is concerned with the classification of statementsmade by critics about works of art as "critical descriptions," "criticalinterpretations," and "critical evaluation