Genre Requirements

 

In hard sf, when a spaceship moves faster than light, Poul Anderson has to present a scientific rationale, e.g., in his Technic History, a rapid succession of quantum jumps of the entire ship, whereas, in fantasy, when a sea vessel moves with supernatural speed, magic or the will of a god is a sufficient explanation.

In Virgil's Aeneid, Neptune, favouring one captain in a boat race, reaches up and moves that boat forward by hand! Another captain, realizing what must be happening, rallies his men by declaring that the first place is the gift of the gods and that men must strive for second place.

In Poul Anderson's multiverse, universes with quantum jumps and gods coexist and there is some limited contact between them but never enough to compromise the integrity of the distinct genres.

It is a matter of individual taste which kind of narrative we prefer.