the epr experiment-which is how he thought of it-involved two spinning electrons , paired and spinning in opposite directions on their respective axes so that their total spin always equals what the physicists referred to as zero , the opposite directions negating each other-and , this being part of the order of the particle universe , they always do ; should one electron shift direction of the spin , the other will , too , instantly , to maintain the zero-which must not , not even for a millionth of a millionth of a millionth of a second , be allowed to be other than zero , no matter how far apart spatially .