Prospects for finding unexpectedly low thresholds for the biological effects of exogenous ELF fields

Seemingly trivial exogenous ELF fields can have readily detectable biological effects if there is sufficient concentration of the fields upon appropriate structures, if each structure so affected modulates an associated sensitive process, and if the outputs of an ensemble of such processes are subsequently integrated; this mechanism is illustrated by the well-known sensitivity of sharks and rays to applied electric fields. Moreover, if an exogenous influence affects a physiological variable at all and if the probability distribution of that variable is related to the incidence of an observable sequela, then the incidence of that sequela can be doubled by an arbitrarily small change of the influence if the observable sequela was sufficiently rare to begin with! Finally, it is asserted that neither a specialized sensory system in an aquatic organism nor a speculative mechanism by which the incidence of rare events might be increased is sufficient to demonstrate convincingly the existence of ELF bioeffects of relevance to humans: only positive experimental data, quantitatively replicable upon demand, suffice to do that; and the generation of such data should be the primary goal of ELF bioeffects research.