 Other accounts of reduction also countenance the levels concept, albeit in different ways. In his “ruthless” account of reductionism, Bickle (2003) abandons the idea of reduction progressing stepwise from level to level, and argues that cellular and molecular neuroscience can directly replace psychology. If one can intervene onto the molecular level to change variables at the behavioral level, then, Bickle contends, one has discovered the “genuine” causal mechanism for those variables (Bickle 2003). Here ‘levels’ figure into ruthless reductionism as useful fictions, where intermediary levels such as tissues, organs, and the like provide a scaffolding for emerging molecular-level explanations. These intermediary levels exhibit “merely” heuristic value, but only in the service of constructing behavior-to-molecules reductions (Bickle 2003: 130).