Response Learning Disabilities: Definition or Specification? A Response to Kavale and

Learning disabilities (LD) need not be defined as such. It is satis-factory to explain what is meant by "learning ' and "disability." Disability is conceived as a structural disturbance of a particular ability. In principle, LD is a psychological term dealing with many different kinds of psychological traits or processes, and their distur-bances, respectively. LD is to be strictly distinguished from more educationally conceived "learning failures, " as well as from more medically/neurologically conceived "dysfunctions " of learning. The label LD cannot be used in clinical practice as a diagnosis, or in research as an independent variable. For both purposes, LD must be specified and/or operationally defined. If a definition ofLD (or specific LD) is needed for professional communication, then a more sophisticated definition than those currently in use is needed as a starting point for further relevant discussion. THE DIFFUSENESS OF the definition of learning disability (LD) has been very precisely described by Kavale and Forness (1985a, 1985b). Although they have ac-curately analyzed the topic from the point of view of the history of science, Kavale and Forness have not done so from the point of view of the philosophy of science. Consequently, the issue remains open for further discussion, to which I feel obligated to contribute with a few propositions that I hope will be seen as provocative and constructive. W h y Definition Is Important As the starting point for discussion, I pose this question: Is it reasonable and appropriate to strive for a definition of LD? More specifically, textbooks on logic and research methodology suggest that some definitions are constructed from labels for generally known or previously defined phenomena; they are, therefore, self-explanatory. If the components of a term are already defined, the new term does not require definition, but only an explanation of what it signifies in a particular context. In fact, the label LD rep-resents just such a general term for known phenomena relating to learning abilities that are somehow disturbed. Consequently, instead of defining LD as a new term, it is sufficient merely to explain what is to be understood by the component terms "learning " and "disabilities.&quot