The Emergent Origin of the Speed of Light Constant: Maximum Signal Speed in Emergent Spacetime

The speed of light in vacuum, c, is a core constant in modern physics, but in standard theories, it is merely an empirical parameter derived from observational induction. Based on the Instantaneous Teleportation Cosmos (ITC) framework, this paper derives the constant nature of the speed of light from first principles. The ITC framework takes “zero-latency transmission between any two points in the universe” as its first principle, redefining spacetime as an emergent phenomenon from the absolute basal structure. Within this two-layer reality framework, the speed of light c is not a fundamental constant, but the maximum signal speed in the emergent spacetime. By introducing the manifestation time τ of basal information in the emergent spacetime and utilizing the homogeneity and isotropy conditions supported by cosmological observations, we strictly derive the linear relationship between spatial distance d and propagation time T, i.e., d = c·T, where c = 1/(ρ¹/³τ) is uniquely determined by the basal node projection density ρ and the manifestation time τ, and is the same for all observers. This derived c matches the experimentally measured speed of light in vacuum. This derivation reduces the constancy of the speed of light from a fundamental postulate to an emergent result, providing a new perspective for understanding the nature of spacetime.