Might what Lewis said about his space travel stories give us any clues about his fantasy writing in general: «No merely physical strangeness or
merely spatial distance will realize the idea of otherness which is what we are always trying to grasp in a story about voyaging through space: you must go into another dimension.»
As Whitehead observed, since the advent of relativity, «spatial relations must stretch through time» (Whitehead 1925, p. 6); in other words, there are only spatio - temporal, but
no merely spatial distances.