Magnetism was once thought to be distinct from electricity until the same equations were found to describe both. Today light is said to be an electric vibration sustained by the magnetic vibration it creates, even though it is impossible for two forces to mutually cause each other!
A static charge isn’t magnetic but when it moves, a magnetic field appears around it (Figure 5.10). So if you wrap a wire around a nail and pass a current through it, the nail becomes a magnet. The magnetism stops when the current stops, suggesting that electricity causes magnetism. Yet if you wrap a wire round a magnet and spin it, a current is induced in the wire so by the same logic, magnetism causes electricity. That electricity causes magnetism that in turn causes electricity is just another paradox that current physics has learned to live with because physical realism can go no further.
If magnetism is charge in another guise, why don’t magnets affect static charges? Why does magnetism act at right angles to the electric field? Why does it reduce more as an inverse cubic function not an inverse square like electricity? Also, dividing a charged body gives positive and negative parts but dividing a magnet gives two magnets each with north and south poles, not a north pole and a south pole. These differences suggest that magnetism is somehow different from charge, even though both are somehow connected.
In current physics, when charges repel, virtual photons are said to batter them apart and when they attract, virtual photons are said to push them together. Magnetism is also attributed to the same virtual photons, even though it works quite differently. As long as the equations work, physics it seems would be happy to attribute electromagnetism to fairies with photon wands.
We understand electricity and magnetism separately but that doesn’t explain electromagnetism any more than understanding horses and birds would explain a winged horse. That a field can be electric or magnetic depending on reference frame doesn’t explain how one field has two different effects (electric and magnetic) that work in different directions and weaken differently. Physics has no answer because it has never addressed what electromagnetism actually is.
Yet Maxwell’s equations connect magnetism to electricity, so:
“We will see that magnetism and electricity are not independent things – that they should always be taken as one complete electromagnetic field.” (Feynman, Leighton, & Sands, 1977)
Quantum realism now suggests that electric and magnetic effects both come from the quantum field.