Newton’s world solid, mechanical, predictable, and closed. Everything that happens is the direct result of forces acting on matter. In such a world, a god could exist only as another physical object — bound by the same laws, limited by the same constraints, and unable to act beyond the machinery of nature. This produces the “grey‑headed old man” problem: a god who is present, perhaps, but not powerful in any meaningful sense.
Einstein’s world softens the machinery but keeps the determinism. Space and time become geometry; gravity becomes curvature; motion becomes relative. But the system remains complete. A god here would not be physical, but would still be confined to the structure of spacetime itself — unable to intervene without rewriting the geometry of the universe. This is a universe that allows elegance, but not agency.
Planck’s world is different. At the quantum scale, reality is not fully real until it is observed. It exists partly as potential, partly as probability, and partly as information. This is the first universe that is not closed, not fixed, and not fully determined. Only a semi‑real, quantum world leaves room for an effective God — not a physical being inside nature, but an informational presence acting through the structure of reality itself.