Rationales For ESP

James Blish's works include at least four fictitious scientific rationales for telepathy or ESP:

Jack Of Eagles;
"Get Out Of My Sky";
"Nor Iron Bars" and "This Earth Of Hours";
Midsummer Century (London, 1975).

However, when telepathy has been rationalised, it is not always clear that it remains telepathy. In Midsummer Century, Martels discovers that:

telepathy does diminish with distance;
"...it had probably started as nothing more than a sort of riding light by which like minds and like intentions could be detected..." (p. 61);
in that case, it would be selected out in favour of intelligence, leaving "vestiges" (which are explained differently in "Nor Iron Bars");
the vestiges might include mob psychology (not what we think of as "telepathy") which is anti-survival and should be selected out;
telepathy conveys emotions but not thoughts or images and requires mutual visibility;
it is simply a field force interacting with other such forces -

- but this seems to leave out everything that we would describe as "telepathy"?