Richard Feynman suggested anti-particles behave like they are traveling back in time. We think that is nonsense: in a ring current model, one distinguishes matter and anti-matter by the direction of travel of the charge inside. That is all. Using (or abusing) Minkowski’s notation, we may say the spacetime signature of an electron (or an antiproton) is + --- while that of a positron (or proton) would be + +++. Indeed, in the ring current model of matter-particles, the magnetic moment alone does not allow one to distinguish between an electron with spin up and a positron with spin down. All we know is that the current that generates the magnetic moment must be different: one carries a negative charge, and the other carries a positive charge – and the direction of the physical current (the motion of the zbw charge) is opposite. The question then becomes: what distinguishes the positive and a negative zbw charge inside the zbw electron and positron? We suggest that the assumption of a (finite) fractal structure, in which the zbw charge itself also spins, may provide a logical answer to that question. The second topic of this paper are ‘other questions’ on the ring current model. Indeed, we all do have a number of philosophical or conceptual questions on the ring current model, which we thought we might, perhaps, insert in this paper – if only because we didn’t quite know where to put them else.