01.KO - Information is Physical

Domain: physics
Date: 2026-04-02

Claim: A major tradition in physics treats information as inseparable from a physical representation. A stored bit, written symbol, transmitted signal, or recorded measurement must be represented by a physical system.

Problem: This physical requirement is often used when discussing computers and thermodynamics, but similar information processes in other fields may be dismissed as metaphor without first checking whether they have identifiable physical signals, states, and changes.

Why this is a problem: Calling a description metaphorical does not establish that the process is unreal. If a physical carrier and a measurable change can be identified, the proposed comparison should be tested on its evidence rather than rejected because it crosses fields.

Why it matters: Dismissing a comparison too early can hide the same relationship or process appearing in different physical systems. It can also make information seem less real in fields that study people, language, or social systems than it does in computer science.

Plain summary: Information that can be stored, transmitted, measured, or used requires a physical representation.

Authorship and evidence

• The cross-field diagnosis is Summer’s original analysis.
• Landauer supplies the published physics position that information requires physical representation.

Sources

• Rolf Landauer — The physical nature of information, Physics Letters A 217 (1996): information is tied to physical representation and therefore to the limits and possibilities of physical law.
• Rolf Landauer — Information is a physical entity, Physica A 263 (1999): https://doi.org/10.1016/S0378-4371(98)00513-5

Related notes:
03.KO - Information Processing Is Subject to Physical Law