We are told that the supernatural is the domain of religion, of spirituality, and lies outside of science. It is said that science deals with the natural world only, and the supernatural is therefore off-limits. It is asserted that posing questions and finding answers through observation is simply not a valid way to knowledge when it concerns the supernatural.
Under Nominalist Determinism it becomes clear that this is a fiction. In this framework, there remains no valid notion of the supernatural at all. By keeping to what we know about the world, using the only methodology that has ever reliably informed us about objective reality, we strip away the abstract things and notions that do not actually exist (the reifications), and land on a base, the substrate, that constitute all of the things we operationally know to be real, namely matter and space.
As this applies to every natural process, we arrive at the conclusion that every product of the brain is built by matter, moving about and interacting according to its habits. These habits of matter are what we discover and express as laws of nature. Consequently, every thought is a change in (brain)matter — neurons, glial cells, vascular cells, fluids and extracellular matrix, and signaling molecules — and this substrate is all there is. Software is hardware.
By moving from "thought is a ghost" to "thought is a physical configuration," we turn psychology into a branch of engineering. Rather than merely asserting that everything is substrate, we use this Nominalist Determinism framework, with its semantic audit, as a universal acid to dissolve any supernatural claim.
I. Thought is Matter
A thought is not a ghost inhabiting the brain. It is the brain: a specific physical configuration of neurons, glial cells, and signaling molecules, changing state as electrochemical gradients shift and synapses fire. There is no separate mental event running alongside the physical one; there is only the physical event, which we call a thought because of what it does, not because of what it is made of.
This matters because it eliminates what philosophers call the interaction problem before it can arise. If thought were something other than matter, we would need to explain how it manages to move matter — how the immaterial pushes the physical. Jaegwon Kim made this point precisely: for a mental event to have any causal power at all, it must be the physical event. There is no other option. A thought that causes nothing is not a thought; a thought that causes something is matter.
The semantic audit applied here is simple: "mind" and "thought" are nominals for physical configurations of the substrate. They name real things — the configurations are real, their causal consequences are real — but they do not name a second kind of stuff. Software is hardware.
II. Elisabeth's Ghost
Any entity that acts on the world must touch it. This is not a philosophical preference, but a physical constraint. To move an atom, you must reach it. To reach it, you must occupy space. To occupy space, you must be matter.
Princess Elisabeth of Bohemia saw this clearly in 1643, in her correspondence with Descartes. If the soul moves the body, she asked, how? What is the mechanical interface? Descartes never answered satisfactorily, because there is no answer that does not smuggle matter back in. Any push requires a surface. Any surface is physical. The ghost that moves your hand is, at the moment of moving it, not a ghost.
This applies without exception. A spirit that fires a neuron must displace the surrounding cellular fluid, scatter adjacent molecules, and generate the molecular agitation that we call heat. A spirit acting directly on electrons or charges fares no better: electromagnetic interactions require photon exchange, and photon exchange is a measurable physical event. These are not incidental effects — they are the interaction. An entity that leaves no physical trace has, by definition, never acted. And an entity that does leave a physical trace is, by definition, part of the substrate.
There is no outside from where to push.
We notice a deeper point here. Some will grant that spirits must cross a boundary into the natural realm to act, while insisting they originate beyond it. But this concedes too much to the supernatural, because for a spirit to exert a physical force, it must itself possess the capacity for physical force. That capacity is a physical property, and an entity with physical properties is a physical entity. The supernatural therefore does not become natural at the boundary. It was never anything else but physical, and the boundary was always fictional.
III. The Physics of Spirits
To perceive the world, a spirit must receive information from it. In the physical world, visual information travels as photons — discrete packets of momentum that interact with matter by transferring that momentum on contact. A spirit that sees must intercept photons, and this spirit thereby deflects or absorbs those photons. Deflected or absorbed photons do not reach what lies behind the spirit. The result is a shadow.
An invisible spirit is therefore a physical contradiction. Invisibility means photons pass through unaffected. But a spirit through which photons pass unaffected has received no information from them. It is blind. It would be physically impossible for such a spirit to see without casting a shadow.
The same logic extends to any sensory interaction. To hear, a spirit must disturb the pressure waves we call sound. To touch, it must displace matter. Every mode of perception is a mode of physical interaction, and every physical interaction leaves a trace in the substrate.
A spirit that perceives the world is part of the world.
IV. The Divine Substrate
Observation is the primary source of knowledge. If a deity exists as a real entity, i.e., one that acts in the world, creates, intervenes, or performs miracles, then it interacts with the substrate. Any interaction with the substrate is, by the argument of section II, a physical event. Physical events are in principle observable. An observable entity is part of nature and therefore subject to the same investigative methods we apply to any other natural phenomenon. The scientific method is precisely the tool for detecting and modeling entities that interact with the world. A deity that is genuinely real is therefore not exempt from science. One could argue that it would be science's most important potential discovery, though I root for aliens. The consistent theist, if genuinely committed to the existence of a real acting deity, should be the most rigorous empiricist of all.
Biologist Kenneth Miller, a practicing Catholic and author of Finding Darwin's God, proposed that God acts by manipulating the outcomes of quantum mechanical events — nudging the results of otherwise random processes without violating physical law. It is the cleverest available move for a scientifically literate theist. But it does not survive the substrate audit. Probability distributions are nominal descriptions of our uncertainty about what matter will do, not things that exist independently and can be adjusted from outside. To shift an actual outcome, God must touch matter. There is no knob with which the distribution can be tuned, except for the substrate itself. A miracle large enough to be recognized as miraculous implies a physical anomaly large enough to be detected by ordinary scientific observation. It has not, and we are epistemologically forced to infer one thing. A God who acts only at quantum scales, invisibly and indistinguishably from noise, is a God whose existence makes no observable difference. Within the ND framework, that is equivalent to not existing at all.
The retreat from observation into testimony, revelation, and faith is therefore a revealing diagnostic: it signals that the claim is not structured as an assertion about the territory, but as the social and psychological practice that it reveals itself to be. While not necessarily dishonest, that is a different kind of claim, and one that cannot be evaluated by the same standards as claims about what actually exists independently of who observes it.
V. Conclusion
Arthur C. Clarke observed that any sufficiently advanced technology is indistinguishable from magic. In Nominalist Determinism, it extends further, to explaining where the supernatural comes from. What we call magic is either a fiction, or a natural process we have not yet identified, or a technology we do not yet understand. Under no case does it escape the substrate, because anything that affects the natural world must itself be natural, and thus observable. The supernatural is not a coherent domain beyond nature, but merely a nominal we apply to our own ignorance of nature.
The semantic audit applied throughout this essay has not disproven any specific deity or dismissed any particular spiritual tradition. It has done something more fundamental: shown that the entire category of the supernatural is incoherent. Any entity that acts leaves physical traces. Any entity that leaves no trace has never acted. Any entity that acts and leaves a trace is in principle observable and subject to investigation. There is no domain left in which the supernatural can hide.
The universe is not haunted, not supervised, not a product of will, desire, or intention operating from outside the substrate. It is substrate moving according to its habits, producing everything we know, including the minds that ask these questions. That is the most honest account we have.
Software is hardware.
Bjørn Østman, Svendborg, June 2026.
