Rules have been defined, within behavior analysis and without, as stimuli that “refer to” or “specify” contingencies or environmental events (e.g., “Hold the base firmly and turn the top to the right,” Skinner, 1969, p. 139). Ribes-Inesta 1 (2000) suggests that the approach to rules and rule-governed behavior that developed from Skinner’s (1969) work leads to conceptual confusion. Specifically, he proposes that confusion results from the lack of a distinction between rules as stimuli and rules as outcomes. Although such a distinction may be necessary, Ribes-Inesta does not address the referential or specifying nature of rules and, consequently, fails to provide useful definitions of rules as either verbal stimuli or responses. In the first part of this response, we will outline the approach to rules and instructions provided by Ribes-Inesta’s article. In the latter half, we will point out the limitations of the definitions of rules and instructions that Ribes-Inesta proposes and, more specifically, how the inadequate definitions of rules and instructions result from the failure to address the referential nature of rules as verbal stimuli or responses. Finally, we suggest that a consideration of RibesInesta’s article draws attention to reference as a critical property of rules and rulegoverned behavior. Ribes-Inesta’s Proposed Redefinition of Rules and Instructions Ribes-Inesta suggests that the approach to rules suggested by Skinner is not clear. More specifically, he points out that a distinction must be made between “rules” that are “constructed as verbal stimuli that describe consequences” and “rules” as “instructions to be followed to cope with a set of already specified.