The I-gen (異元): A Hypothetical Layer Beyond the Observable Universe and the Boundary of Scientific Inquiry

The Dual-Layer Universe model (Koku-Genki) posits two fundamental layers: the structural layer (刻宇宙, Koku Universe) and the energetic layer (元気宇宙, Genki Universe), separated by the 間 (Ma) — an energetically active domain. This paper extends the model by proposing a third, deeper layer: the **異元 (I-gen)**, defined as the origin point within the 間 itself. The I-gen is hypothesized to be the source of the 間's energy gradient and lies beyond the boundary of empirical observation — analogous to the role of imaginary numbers in mathematics: not directly measurable, yet structurally necessary for the model's coherence. We argue that the I-gen corresponds to what has historically been designated as the domain of the divine (神仏の領域) across multiple cultural and philosophical traditions — and that th