  Von Neumann explicitly referred to Szilard's argument in (von Neumann 1932, Chapter V.2), when discussing the irreversibility of wavefunction collapse on measurement, although it is unclear precisely what role this was intended to play. Both Gabor and Brillouin's measurement procedures, using light, required the quantised treatment of the electromagnetic field to produce dissipation. Gabor stated quite clearly his belief that measurement by classical electromagnetic fields could take place non-dissipatively and would lead to unconstrained violations of the second law. The Landauer-Penrose-Bennett argument does not require measurements to generate heat, so for them, classical statistical mechanics need not lead to untamed demons. Although it might still be argued that quantum electrodynamics dissipates heat if used for measurement, the fact that some physical processes for measurement dissipate heat does not undermine Bennett's claim that other physical processes can perform measurements non-dissipatively.