Science fantasy is a hybrid genre within speculative fiction that simultaneously draws upon or combines tropes and elements from both science fiction and fantasy. In a conventional science fiction story, the world is presented as being scientifically logical; while a conventional fantasy story contains mostly supernatural and artistic elements that disregard the scientific laws of the real world. The world of science fantasy, however, is laid out to be scientifically logical and often supplied with hard science-like explanations of any supernatural elements.
During the Golden Age of Science Fiction, the fanciful science fantasy stories were seen in sharp contrast to the terse, scientifically plausible material that came to dominate mainstream science fiction typified by the magazine Astounding Stories. Although at this time, science fantasy stories were often relegated to the status of children's entertainment, their freedom of imagination and romance proved to be an early major influence on the "New Wave" writers of the 1960s, who became exasperated by the limitations of "hard" SF.
Distinguishing between pure science fiction and pure fantasy, Rod Serling claimed that the former was "the improbable made possible" while the latter was "the impossible made probable". As a combination of the two, science fantasy gives a scientific veneer of realism to things that simply could not happen in the real world under any circumstances. Where science fiction does not permit the existence of fantastical or supernatural elements, science fantasy explicitly relies upon them to complement the scientific elements.
In explaining the intrigue of science fantasy, Carl D. Malmgren provides an intro in regards to C. S. Lewis's speculation on the emotional needs at work in the subgenre: "In the counternatural worlds of science fantasy, the imaginary and the actual, the magical and the prosaic, the mythical and the scientific, meet and interanimate. In so doing, these worlds inspire us with new sensations and experiences, with [quoting C. S. Lewis] 'such beauty, awe, or terror as the actual world does not supply', with the stuff of desires, dreams, and dread."