Christianity is heading for a full allegorization

[polymath257]

Well it does kinda depend on your definition of substance. But, as far as definitions of "substance" go, I like drawing the line at "must interact with physical reality."

You are pretty empirically-minded, Poly, so think about it. If there IS some kind of thing out there that doesn't interact with physical matter or energy at all, it may as well not exist. We'll never sense it. We'll never know it. And if we do somehow sense it or detect it- Boom. That's interaction.

It makes sense to define substance as something that MUST interact with physical matter or energy.

Interact is the keyword.
How does matter interact with matter?
An electron interacts with another electron or any other charged particle via its electric field/magnetic field.

A neutrino, a neutron, a photon does not interact with an electron via the electric force/magnetic force.

I think that neutrinos, a neutrons, a photons can all interact together via the their gravitation forces (if you want to accept that gravity is a force. There is another concept that sees gravity as a deformation of space. I think the electric force/magnetic force can also be viewed that way.).

There is a strong interaction between baryon particles, such as neutrons, protons, anti-neutrons, anti-protons. At close distances, they can bind together.

There is another force called the weak force. Neutrinos interact with other particles via the weak force.

So, it looks like all interactions are done via fields.
If one particle has field X and another particle has field Y, they will not interact with each other.
If one particle has field X and another particle has field Y and also field X, they will interact via field X.

So what Angrboda said makes sense.

A LOT of care is required here.  Several statements are either wrong or seriously misleading.

First, all particles are associated with a field and vice versa.

So, there are electron fields. And the electromagnetic field is associated with photons.

This means that each of the forces is described by an exchange of some particle.

When two charged particles interact electromagnetically, they do so by the exchange of a photons. So, you were wrong when you said that photons do not interacts with electrons via the electromagnetic force. In fact, the electromgnetic force is *precisely* charged particles interacting with photons.

You were also factually wrong when you said that neutrons do not interact electromagnetically. While they are not charged, they *do* have a magnetic field.

The weak force is the exchange of W and Z particles. So, leptons and quarks interact via W and Z particles and that interaction is the weak force. Neutrinos are one type of lepton. Here, the W particles are charged and the Z particles are electrically neutral.

The particles associated with the strong force are called gluons. There are 8 types of gluons.

Now, there *is* a difference between the 'matter' particles and the 'force' particles. The 'matter' particles are all fermions (electrons, quarks, neutrinos), while the 'force particles (photons, W, Z, and gluons) are all bosons.

BTW, the particle for gravity is called the graviton and is spin 2. We can *also* consider gravity as the curvature of spacetime: the two descriptions are mathematically equivalent.

For each basic interaction, there is a diagram detailing that interaction. So, the diagram for an electron and a photon just has the photon, an incoming electron, and an outgoing electron. Because of symmetries, this same diagram describes the interaction of positrons and photons and describes both a single incoming photon or a single outgoing photon. For any given observed interaction, we have to write down all of the diagrams with those incoming particles and those outgoing particles and 'add them up' to get the probability of that interaction and its properties.

Interactions with W and Z particles can change leptons to quarks and vice versa. Interactions with gluons can change the type of quarks.