This idea of a non-physical realm that transcends the physical has been a persistent one. What this even means will usually depend on who you ask. However, it usually has something to do with ethereal spirits working within arbitrary laws that have little or nothing to do with the physical laws we are familiar with. Sometimes it is the realm ghosts inhabit – the disembodied spirits of people who’ve died. Sometimes it is described more as a divine realm where angels and souls exist, somehow able to communicate actions into the physical realm when it pleases them. What spiritualism always has in common, though, is that it has everything to do with human beings.
In this section I discuss why spiritualism is, at best, a hypothesis that should be rejected as an explanation for consciousness.
Spiritualism is an anthropocentric idea because it was invented by humans who figured themselves to be the reason anything exists at all. The spirit realm is where purpose and free will and salvation reside. Magical thinking of all kind has always held humanity up as a paragon of existence. Magical spells purport to alter the laws of the entire universe because someone mumbled a few words in a language invented by humans for human communication. Superstitions arise because people believe their actions and words have some sort of ontological necessity over the way nature progresses.
Spirits are simply another form of this same flavor of egocentric magical thinking. Not only is the world of spirits focused on the behaviors and thoughts of humans, but it is also the purer and more important level of existence – it is divine, transcendent, and without the corruptions that come with a fleshly existence. What a spirit is, of course, always goes without explanation. Indeed, the fact that it defies explanation only lends credence to the spiritualness of it – spirits are by definition conveniently beyond explanation. This allows anything one wishes to be attributed to such sprites.
What also goes unanswered is how the spirit realm interacts with the physical world. This is an issue that’s at least as old as Descartes, who though the immaterial mind inexplicably communicated with the body via the pineal gland.
Today people might chalk the interaction up to just another aspect of the mysterious spirit realm that we cannot and never will understand. However, to say that some parallel – or transcendent, if you will – realm is reaching into our own and interacting with it, this would have physical effects that we could observe.
The first law of thermodynamics says that energy cannot be created or destroyed. This is an oversimplification. Emmy Noether’s theorem says that energy conservation is a time translation symmetry, but in Einstein’s theory of general relativity, this symmetry is broken5. This is how light can be red-shifted – lose energy – due to the expanding universe. The energy lost from the red-shift of light from other stars is not given off anywhere, but simply lost due to the stretching of spacetime itself increasing the wavelengths of the radiation.
What we can say, though, is that on the scale of the human brain, energy conservation holds because the time translation symmetry is not broken on such small scales – there is no measurable dynamic flux of spacetime.
If we were to postulate a spirit world that can interact with our own world, though, we would predict seeing increases in energy and breaking of time translation symmetry. When a human soul, acting from the spirit realm outside the closed system of the universe, caused the movement of ions inside the brain in order to induce thoughts, this would introduce new energy into the universe. There would also be a corresponding breaking of the time translation symmetry associated with energy conservation, which would cause observable changes in spacetime around the heads of human beings. Neither the introduction of new energy nor alterations in spacetime around people’s heads are observed.
One idea I can imagine people posing to this is that the passage of time is subjective. Perhaps time dilation does occur when we enter a flow state and the world seemingly passed by at an accelerated pace? This does not hold up because A) from our inertial frame of reference, time should still feel as if it passes normally – it would be everywhere else where time went fast – and so it has nothing to do with subjective time and B) the movement of ions in the brain does not change pace substantially depending on how hard one is thinking. Most brain activity is used for subconscious processes, so there would be no substantial change in the experience of passing time.
The second law of thermodynamics says that the total entropy of the universe always increases. This also takes the universe to be a closed system. An open system, such as the earth, can see a decrease in entropy because it gains energy from the sun. That energy can be used to do work, which can decrease local entropy, but still increase the total entropy of the entire universe.
A world of spirits able to interact with our universe, though, would mean that this law would not have to hold. Our universe would not be a closed system, but in fact an open system within the larger system containing the physical universe and the spirit realm. We would be able to observe decreases in local entropy without corresponding increases in total entropy throughout the universe.
Really, though, the idea of a physical-spiritual dualism, aside from not agreeing with observations, just does not have any explanatory power. Ideally what it would explain is why physical material, having no conscious experience itself, can organize into the brain and have any sort of accompanying consciousness. This merely pushes the explanation back: how is it that a soul or spirit can have consciousness? No question has been answered in such a case, instead just having the answer relegated to the realm of the inexplicable. That, of course, does not mean it is not true, but without actual evidence of a spirit realm – and, indeed, evidence that there is none, at least, that interacts with our physical world – why would we posit one?