James Henry Fetzer (born December 6, 1940) is a philosopher of science and conspiracy theorist. Since the late 1970s, Fetzer has worked on assessing and clarifying the forms and foundations of scientific explanation, probability in science, philosophy of mind, and philosophy of cognitive science, especially artificial intelligence and computer science.
In the early 1990s Fetzer began promoting John F. Kennedy assassination conspiracy theories, then later 9/11 conspiracy theories, Holocaust denial and conspiracy theories regarding the 2002 death of Senator Paul Wellstone. He cofounded Scholars for 9/11 Truth in 2005, and claims that the United States government and the Israeli government are involved in these and other conspiracies. Fetzer's allegations and speculations have drawn strong criticism.
Fetzer was born in Pasadena, California, on December 6, 1940, to a father who worked as an accountant in a welfare office in Los Angeles County, and grew up in a neighboring city, Altadena.