is the apparent dominance of the electric component of the Lorentz force expression at low frequencies, a field-related conception that draws attention away from the rising importance of the magnetic component of a propagating field as the frequency declines [@hr75; @hr82]. Inappropriate emphasis on the electric field has caused conceptual errors even in relativistic phenomena, as discussed in Section IV in the context of vacuum pair production. A potentials-related approach obviates this electric-field-dominance hazard. The concept of the *critical field* is often mentioned in connection with strong-laser interactions [@arb; @ssb]. The critical field refers to that value of electric field at which spontaneous pair production from the vacuum becomes significant. It has been applied to laser fields in terms of the electric component of a plane-wave field. This is devoid of meaning for laser beams in vacuum because pure electric fields and plane-wave fields are disjoint concepts, as is evident from Section II. The conservation conditions applicable to critical-field considerations cannot be satisfied by a laser. Even were the electric component of a laser field equal to the critical field, pair production cannot occur because pair production from the vacuum by a laser pulse cannot occur unless there is a 