Another comment the TVTropes article makes is that the “hardness” of SF doesn’t relate to realism. So what is realism, anyway? One definition is that it’s a philosophy that accepts things as they are and deals with the situation. On the other hand, it means a literary quality of representing a person or a situation accurately in a true-to-life way.

Science fiction might pass on the first definition, but you can see where it would fail on the second one. For one thing, good, well-thought out SF is often concerned with different worlds or societal structures or changes in human nature brought about by advances in technology. If it’s well-done, then it gives us a glimpse of a possible future, but not necessarily one that true to the present. TVTropes notes that some works that “some works that barely qualify as SF might be unsparingly realistic … and some of the hardest SF imaginable might deal in out-and-out fantasy.”

So, is realism a desirable quality in SF? It’s always nice if readers can actually identify with the characters in a story, so a reasonable correspondence to the current human condition is helpful. Because realism means avoiding fantastical and supernatural elements, then this would also be the characteristic that separates science fiction from fantasy. But actually, most people have an idealized idea of reality. According to some research, the clinically depressed have the most accurate view of reality.

What fun is that?