This standalone preprint presents the basic principles of Relative Duality, a relational approach to foundational physics in which no background, observer, descriptive role, or external law is physically preferred at the fundamental level. The article introduces the core postulate that physical content consists only of relations and quantities invariant under admissible exchanges of descriptive roles. The paper is written as an accessible foundational note, partly in the spirit of early principle-based formulations of relativity. It explains the intended reciprocity between information and transformation, state and law, geometry and interaction, observer and effective law, and symmetry and admissible dynamics. At the formal level, the article summarizes the role-exchange idea through invariants, equivariant rewriting, and a mutual-commutant relation between represented role symmetries and compatible laws. The article also states a conditional observer-relative reading of space, energy, time, and neutrality, and briefly discusses how the standard Born probability form may be interpreted as an information–transformation pairing once a quantum event structure is assumed. These discussions are explicitly conditional and are not presented as derivations of established physical theories. This work does not claim to derive observed particles, the Standard Model, measured constants, general relativity, quantum field theory, or quantum measurement probabilities from first principles. It is intended as a concise statement of the foundational principles and open requirements of the Relative Duality research program.
Daniel Hendriks (Sat,) studied this question.