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  • Print publication year: 2018
  • Online publication date: May 2018

10 - Intension in the Physics of Computation: Lessons from the Debate about Landauer’s Principle


In this paper the key issues in the debate about Landauer's Principle are identified, and important lessons are drawn about how our view of computation and physics relates to and is informed by the interpretation of thermal physics. It is argued that there are several respects in which modality, and how processes and systems are represented, are crucial to both Landauer's Principle and the application of thermodynamics. After reviewing the L-machine model of Ladyman, Presnell, Short, and Groisman (2007) as an exemplification of a general account of computation and its physical realization, John Norton's supposed no-go theorem for the thermodynamics of computation, and work by David Wallace (2014) on the nature of the Second Law of thermodynamics and the relationship between thermodynamics and statistical mechanics, it is argued that both computational and thermodynamic states are intensional, but that the modal structure of physical states that represent them can nonetheless be taken to be an objective component of implementation.