Hal Clement was born Harry Stubbs on May 30, 1922 and died on October 29, 2003. In addition to being an author, Clement was an artist, using the name George Richard for his artwork.

Clement received the Ignotus Award for the translation of his novel Mission of Gravity and a Retro-Hugo Award for his short story “Uncommon Sense.” He received the Skylark Award from NESFA twice, in 1969 and in 1997. In 1989 I-Con presented him with the Gallun Award, and in 2001 they presented him with the Moskowitz Award. He received the Forry Award from LASFS in 1992 and was inducted into the First Fandom Hall of Fame in 1997 and the Science Fiction Hall of Fame in 1998. In 1999, the SFWA named him a Grand Master. He was the Guest of Honor at Chicon V, the 1991 Worldcon in Chicago.

“Critical Factor” was purchased by Frederik Pohl for the second volume of Star Science Fiction Stories, published in 1953. It was translated into German in 1977 for an appearance in Titan 4, edited by Pohl and Wolfgang Jeschke. James E. Gunn selected the story as representative of Clement’s work and hard science fiction for his historical anthology series The Road to Science Fiction: Volume 3: From Heinlein to Here.

Clement was one of the masters of rigorous hard science fiction, often exploring the extremes of physical science, as he did in Mission of Gravity, and once he introduces the oddity allows scientific plausibility to dictate the course of his story. In “Critical Factor,” he posits a race of amorphous beings who live within the layers of the earth, eating seams of rock, and to whom the atmosphere is deadly. Pentong has gone on a lengthy journey of discovery and found that there is a distant continent covered in a mile-thick sheet of frozen water. He postulates that melting that water would cause the ocean levels to rise, thereby increasing the area in which they can live since they can only live in earth that is covered by water (not exposed directly to air).

Although the nature of the aliens only is revealed slowly through the course of the story, it is clear from the opening lines that Clement has thought through his premise, done his research, and created an alien race that lives within the crust of our planet. The aliens’ interactions with their environment and their weaknesses are consistent as they apply a version of the scientific method to their theories and explorations. If the story has a weakness, it is that the aliens civilization is a little too similar to our own.

Clement shows them taking the first steps towards discovering more about the nature of their world. It mirrors the steps mankind was taking even in the early 1950s, which would culminate at the end of the decade with the launch of the first satellite and mankind taking the first steps towards discovering more about the nature of the universe around our planet. Perhaps more than any other author, Clement was capable of answering Campbell’s dictum to “Write me a creature who thinks as well as a man, or better than a man, but not like a man.”

Reviewed in its original publication in the anthology Star Science Fiction No. 2, edited by Frederik Pohl, Ballantine Books 1953.

---

Steven H Silver is a sixteen-time Hugo Award nominee and was the publisher of the Hugo-nominated fanzine Argentus as well as the editor and publisher of ISFiC Press for 8 years. He has also edited books for DAW and NESFA Press. He began publishing short fiction in 2008 and his most recently published story is “Doing Business at Hodputt’s Emporium” in Galaxy’s Edge. Steven has chaired the first Midwest Construction, Windycon three times, and the SFWA Nebula Conference 5 times, as well as serving as the Event Coordinator for SFWA. He was programming chair for Chicon 2000 and Vice Chair of Chicon 7. He has been the news editor for SF Site since 2002.