The soul theory’s contradiction with neuroscience isn’t the end to its implausibility; it’s strongly at odds with modern physics as well. While neuroscience may be a more subjective field, physics is certainly not, and here I shall present problems that the soul theory faces according to physics (some of my arguments are directed specifically at ghosts aka wandering souls).
The 1st Law of Thermodynamics
The 1st Law of Thermodynamics, which is the principle of conservation of energy states that the overall energy within a closed system will remain constant, although it may be converted into other forms. For its energy level to change, it must come into contact with another system. In such a case, the energy level of the system will increase if work is done onto the system, and vice versa. As far as evidence goes, the Universe is a closed system.
Here comes the problem. For the soul to be able to do work in the material world, some of the soul’s energy must be converted into physical energy. Since the soul exists independently of the physical universe, the total energy in the universe will increase when the soul does work, and this must mean that the universe is an open system, which is contradictory to modern science.
Another saying that I’ve heard from my friends is that instead of existing in a separate realm, the soul enters the physical world when one is born (or during fertilization, gastrulation etc.). Somehow, the soul can affect physical entities, but not the other way around. This hypothesis doesn’t make sense, as they’re implying that the energy that makes up the soul is limited, and being unable to receive energy from the physical universe, it will use up its energy quickly and cease to exist.
Light
For us to see something, then that thing must either reflect or emit visible light. Ghosts are supposedly visible in quite some anecdotes, but that’s not possible if we’re to follow the usual definition for ghosts. Let me explain.
First of all, a ghost shouldn’t be able to reflect light. For light to be reflected, it must hit a surface. Since the soul is defined as being made up of only energy, there’s no way it can reflect light, and if I’m not wrong, all forms of light emission require matter as a source of fuel. Thus, for us to see ghosts, they must be made up of matter (at least partially). However, as the soul is supposed to survive physical and material death, such a definition is self-contradicting.
Gravity
In every single anecdote that my friends gave me, ghosts have the ability to float. This, however, simply contradictory to most widely established model for gravity – general relativity. Unlike previous models, general relativity describes gravity not as a force, but as a curvature of space-time, and everything in this universe is subject to the effects of gravity – matter, light, electromagnetic waves, energies etc.
If the souls exist within the material plane, then it must be subject to the gravity as well, no matter what it’s made of. No matter what universe you’re in, you’re going to subject to it’s time-space constraints. It’s logically contradictory for a ghost to float and not be affected by gravity. If a ghost is to float, then it must exert force against the centre of gravity. Such an act would require massive amounts of energy, and the soul would quickly cease to exist. Unless the 1st law of thermodynamics is violated, of course.
And by the way, if ghosts are free from gravity, they should be hurtling into space.
Conclusion
Here I have put forward a few points showing that the concept of the soul is quite problematic from the viewpoint of modern physics. It’s a wonder that mind-body dualists can still insist that the soul theory is true even when it contradicts one of the most objective fields of science.
Of course, the list is far from complete, and I would be thankful if anyone can come up with even more ideas showing how the soul contradicts physics.

