Knowing it when we see it

Hard science fiction, the most science-oriented sf, enjoys greater popularity with readers and writers than with critics. Less criticism is written on hard sf than on many other aspects of sf. What criticism exists tends to try to define it compactly, thus making it easier to study retrospectively. What critics usually exclude from the sub-genre either plays too loosely with the facts, or lacks the proper attitude. (The latter is usually considered the more serious transgression.)

Sf's community of writers, readers and editors resists defining genres and sub-genres. In 1999, long-time Analog editor Stanley Schmidt, heir to John W. Campbell's job, remarked: