Landauer Defended: A Reply to Norton

Landauer's Principle states that logically irreversible computations
can only be performed by thermodynamically irreversible physical
processes. Its proof has been challenged by John Norton.  Ladyman,
Presnell, Short and Groisman responded with an analysis of the
implementation of logical operations by physical systems, and a proof
based on the construction of a thermodynamic cycle, essentially
arguing 'if not-LP then not Second Law of Thermodynamics'. Norton's
latest papers repudiate that proof and generalise with a 'no-go'
theorem for the thermodynamics of computation further challenging the
orthodoxy that has Landauer's Principle at its heart.  This paper
argues that Norton's arguments against LPSG fail, and begins a
response to the no-go theorem and his broader concerns.