Kosc's response to our work provides a good example of the complex problems encountered when one attempts to define learning disabilities. Although his approach to an a priori definition of the terms "learning" and "disability" is appealing in its simplicity, it is clear that such terms do not lend themselves to such easy explanation. His narrow interpretation of disability from an "anatomico-physiological" viewpoint further clouds the issue. Kosc apparently fails to recognize that analysis of the definitional problem in learning disabilities goes far beyond the historical imperative of the Strauss and Werner paradigm to more substantial problems that seriously impede scientific progress in the LDfield. K O S C ' S P A P E R O N learning disability ( L D ) definition, which appeared in R A S E 8:1, p r o v i d e s valuable insights i n t o t h e p r o b l e m s i n h e r e n t in defining L D . Alt h o u g h w e find m u c h t o agree with, w e also n o t e p o i n t s o f disagreement w i t h Kosc's analysis. W e w o u l d like t o take this o p p o r t u n i t y t o outline o u r reaction in t h e h o p e t h a t it, like Kosc's paper, will b e p r o v o c a t i v e a n d constructive.