ESP Or Magic

We have seen that the premise of one work can be casually referenced or even summarily dismissed in another work by the same author. For example, in Poul Anderson's The Avatar, the Betans can travel through space-time via T machines but cannot enter or intervene in their own history, unlike time criminals in the Time Patrol timeline. FTL is possible and extraterrestrial intelligences are abundant in some fictional universes although not in others. There are several alternative answers to the question whether conscious AI is possible. And so on. We appreciate such systematically alternative approaches in Poul Anderson's prolific output. We also find something similar in the works of the author whom I think of as paralleling Anderson, James Blish. 

In an early novel by Blish, Jack Of Eagles, ESP is scientifically rationalized and extensively deployed. Several later works by Blish present alternative rationales for ESP. However, in his Black Easter, a black magician, Theron Ware, says to a client, Baines:

"'Then you don't really believe in magic yet - only in ESP or some such nonsense.'"

-James Blish, Black Easter IN Blish, After Such Knowledge (London, 1991), pp. 319-425 AT p. 33.

When Baines' scientific advisor, Adolph Hess, compares black magic to flying saucers, Baines replies that the reasons for thinking that anyone has seen a saucer are pitiable whereas they have seen a demon. Thus, stories about alien visitations are dismissed. 

When travelling underground in a gravity-vacuum tube, Baines' personal assistant, Ginsberg, remarks that riding in such a thing makes it hard to believe in devils. Yes, hard sf and fantasy are usually light-years apart.

Ware refers to magic as goetic art. See also here.