​Harry Potter and the Methods of Rationality (HPMOR) is a work of Harry Potter fan fiction written by Eliezer Yudkowsky, a rationalist philosopher and AI safety researcher who has been influential in raising awareness about potential existential risks from advanced artificial intelligence.

​The work, published as a serial over five years concluding on March 14th 2015, totals over 660,000 words, and has become one of the top rated pieces of fan fiction of all time. It adapts the story of Harry Potter to explain complex concepts in cognitive science, philosophy, and the scientific method. HPMOR was written by Yudkowsky to popularise ideas he pioneered on LessWrong, and became for many their introductory text to contemporary rationalism.

​Let's celebrate the one decade anniversary. Newspeak House is hosting one of several parties going on around the world.

​The Patronus Challenge

​Consider what scientific or rational concept most fills you with wonder and joy. Be prepared to share it as we collectively cast our rationalist Patronuses against the darkness of cognitive biases.