ABSTRACT
W o R K E R S in the field of mental retardation have been unable to agree how mental retardation should be defined. The problem of definition is by no means superficial. Different definitions have reflected opposing theoretical views of etiology and prognosis, and these views have had definite implications for the management and education of the mentally retarded. The issue of whether irreversibility should be included in the definition of mental retardation reflects the importance of the definition.
