Abstract

Various authors insist that some body of natural phenomena are legitimately describable or explainable only on one level of description, and would disqualify any description not confined to that level. None offers an acceptable definition explicitly. I extract such a definition I find implicit in the work of two such authors, J.J. Gibson and Hubert Dreyfus, and modify the result to render it more defensible philosophically. I also criticize the definition Shaw and Turvey offer, demonstrate some applications of my definition, and try to forestall certain misunderstandings of those presuppositions and that definition.