Re: anti-particles "moving backwards in time" ?
"But this is just the mathematics. The physics content is the identification of a mathematical construct with a physical "reality". You start with a physical situation, map it into the appropriate mathematical construct, perform mathematical operations, and map the result back to a physical situation. The intermediate calculations don't map to reality - especially in quantum field theory."
Ah gotcha. Like the imaginary number "i". There isn't a "real" dimension where numbers are all imaginary, it's just a construct to allow you to continue past the thorny "square root of minus one" bit.