Hard Science Fiction - Scientific Rigor

Scientific Rigor

The heart of the "hard SF" designation is the relationship of the science content and attitude to the rest of the narrative, and (for some readers, at least) the "hardness" or rigor of the science itself. One requirement for hard SF is procedural or intentional: a story should try to be accurate, logical, credible and rigorous in its use of current scientific and technical knowledge about which technology, phenomena, scenarios and situations that are practically and/or theoretically possible, and later discoveries do not necessarily invalidate the label. For example, P. Schuyler Miller called Arthur C. Clarke's 1961 novel A Fall of Moondust hard SF, and the designation remains valid even though a crucial plot element, the existence of deep pockets of "moondust" in lunar craters, is now known to be incorrect.

There is a degree of flexibility in how far from "real science" a story can stray before it leaves the realm of hard SF. Some authors scrupulously avoid such technology as faster-than-light travel, while others accept such notions (sometimes referred to as "enabling devices", since they allow the story to take place) but focus on realistically depicting the worlds that such a technology might make possible. In this view, a story's scientific "hardness" is less a matter of the absolute accuracy of the science content than of the rigor and consistency with which the various ideas and possibilities are worked out.

Readers of "hard SF" often try to find inaccuracies in stories, a process which Gary Westfahl says writers call "the game". For example a group at MIT concluded that the planet Mesklin in Hal Clement's 1953 novel Mission of Gravity would have had a sharp edge at the equator, and a Florida high-school class calculated that in Larry Niven's 1970 novel Ringworld the topsoil would have slid into the seas in a few thousand years. The same book famously featured a devastating inaccuracy: the eponymous Ringworld is not (in) a stable orbit and would crash into the sun without active stabilization. Niven fixed these errors in his sequel The Ringworld Engineers, and noted them in the foreword.