"Only if you fail to take the obvious step of looking for the external influence--and finding it in the case of the radio receiver, but not in the case of the brain." The neutrino was hypothesized back in the 1930s solely on the basis of missing mass/energy in beta decay. (One of the papers describing this was rejected by Nature on the grounds that it was too far from reality.) It was only decades later that the neutrino was found (in whatever sense a weakly interacting uncharged particle can be "found"). At any rate, I'm just saying that it's not illogical to hypothesize that the brain is more like a radio receiver than a tape player; whether it really is, is a different question.