It's literally just
"Hey you know how there's like a bunch of particles that don't interact with EM forces?"
"Yeah"
"Well what if there's like a BUNCH of particles that don't interact with EM forces?"
"...oh hey that makes this math way easier"
It's literally just
"Hey you know how there's like a bunch of particles that don't interact with EM forces?"
"Yeah"
"Well what if there's like a BUNCH of particles that don't interact with EM forces?"
"...oh hey that makes this math way easier"