Today I was reading for my Modern Physics class and something I read struck me in a way. The author claimed that all electrons are identical; they have the same measured mass, electric charge and magnetic dipole moment. This statement bothers me, and I haven't been able to stop thinking about it. So I come to you for some closure. How do we know that all electrons are the same? I understand that electrons are measured to have the same characteristics, but without infinitely precise measurements we can only be sure to a certain degree.