The story
rational + or rationalist + -sphere (“designating a particular realm or interest of a group of people, object, etc”)
Etymology from Wiktionary, CC BY-SA 4.0.
rationalsphere
Today it means: An online community of individuals, centered around the forum LessWrong and the blog Slate Star Codex, who discuss philosophy, psychology, and futurism through the lens of Bayesianism and rationality. Full definition →