Landauer's Principle: An Engineering‑Thermodynamic Limit, Not a Fundamental Law of Physics

Abstract

This article analyses Landauer’s principle — the frequently cited claim that erasing one bit of information requires at least kT \ln 2 energy dissipation. This principle is often presented as “proof of the physical nature of information” and as a fundamental link between information and thermodynamics. It is shown that Landauer’s principle is not a fundamental law of physics but represents an engineering‑thermodynamic limit applicable to a certain class of computing devices. The critique is based on the work of Lairez (2024), Alicki (2014), Bennett (1982) and others. Three main problems are identified: (1) confusion between logical and thermodynamic irreversibility; (2) two unnecessary constraints imposed by Landauer on the erasure procedure (one‑to‑one mapping and uniqueness of the procedure); (3) the existence of reversible and quantum computations in which dissipation can be reduced to zero. The three senses of “information” (configuration, observer’s knowledge, pseudosubstance) introduced in Article 1 are distinguished. It is shown that the claim “information is physical” arises from substituting the first sense by the third. A reformulation is proposed: instead of “information is physical”, one should say “in specific computing architectures, erasure has a thermodynamic cost”. Landauer’s principle is analogous to the Carnot efficiency — useful for engineers, but not an absolute limit for all conceivable devices. Keywords: Landauer’s principle, information, logical irreversibility, thermodynamic irreversibility, reversible computation.