Hidden Dimensions is the quiet philosophical floor beneath much of the Secret Space layer: the intuition that reality is layered — that beyond the space we see lie unseen realms, reachable through consciousness or, in the bolder version, through technology.
The real physics underneath
Mainstream physics takes extra dimensions seriously. String theory and its relatives propose additional spatial dimensions curled below detection, and higher-dimensional mathematics is standard working tool. This is genuine, if unproven, science — the respectable seed the thread grows from.
Where it reaches further
The leap is from "mathematical extra dimensions" to "populated hidden realms you can visit." That crossing moves from physics into the map's consciousness and interdimensional territory — meaningful as experience and metaphor, but not established fact. The map keeps the two apart: real dimensional physics on one side, felt or claimed inner realms on the other, each honored on its own terms.
Extra dimensions may well be real; inhabited hidden worlds remain belief. The map keeps the science and the mysticism side by side without collapsing one into the other.