The Gravitational SETI Channel Why Electromagnetic Observation Cannot Detect Cosmological Civilisations, and What Can

The Search for Extraterrestrial Intelligence (SETI) has operated for decades on the assumption that electromagnetic signals are the natural medium for interstellar and intergalactic communication. This paper argues, from the axiomatic structure of Quantum-Geometry Dynamics (QGD), that this assumption is structurally false: the electromagnetic channel is physically incapable of cosmological-scale civilisation detection, and the gravitational channel established by QGD's two axioms is the only channel with the required properties. Five structural limitations of the electromagnetic channel—finite causal depth of propagation, flux attenuation as d⁻², directionality requirement, causal alignment requirement, and background contamination—combine to make electromagnetic SETI structurally precluded at cosmological distances regardless of the technological capability of the transmitting civilisation. QGD's gravitational channel dissolves all five limitations simultaneously: it propagates with causal depth 2 regardless of spatial separation d, its amplitude grows as d² through the n-gravitational interaction G⁻ (a;b) = mₐ · mb · (d² + d) / 2, it is inherently omnidirectional, it requires no causal alignment, and natural and artificial signatures are in principle discriminable by their causal complexity structure. The paper further establishes that the gravitational channel supports passive technosignature detection: any civilisation engaged in technological activity at sufficient scale produces a non-natural gravitational causal signature whether or not it intends to communicate. The Fermi Paradox is reframed: silence in the electromagnetic channel is not evidence for the rarity of civilisations but evidence that we are searching in the structurally wrong channel. A falsifiable observational programme—Gravitational SETI—is proposed, with specific detection targets, detector candidates, background characterisation methods, and a rigorous null-result criterion. All claims are derived from QGD's two axioms; no assumptions about alien technology, behaviour, or intent are required