 Other responses to unlimited pancomputationalism point out that transitions between physical states are not causal in nature. The computational description Putnam relies on maps onto a physical description such that the computational description does not describe the causal structure of the physical system. According to several authors, non-causal mappings are illegitimate (Chrisley 1995, Chalmers 1995, 1996, 2011, Scheutz 1999, 2001). This type of response lends support to the causal mapping account of computation.