Paul Gordon Barker, also referred to as Hermes Pan, is an American musician, best known as the former bass guitarist, producer and engineer for industrial metal band Ministry from 1986 to 2003. Prior to Ministry, he provided bass for the Seattle post-punk ensemble The Blackouts alongside future Ministry drummer Bill Rieflin and his brother, one-time Ministry touring keyboardist/saxophonist Roland Barker, from 1979 until 1985.

Ministry is an American industrial metal band founded in Chicago, Illinois, in 1981 by producer, singer, and instrumentalist Al Jourgensen. Originally a synth-pop outfit, Ministry evolved into one of the pioneers of industrial rock and industrial metal in the late 1980s. The band's lineup has changed frequently, leaving Jourgensen as the sole remaining original member. Musicians who have contributed to the band's studio or live activities include vocalists Nivek Ogre, Chris Connelly, Gibby Haynes, Burton C. Bell and Jello Biafra, guitarists Mike Scaccia and Tommy Victor, guitarist Cesar Soto, bassists Paul Barker, Paul Raven, Jason Christopher, Tony Campos and Paul D'Amour, drummers Jimmy DeGrasso, Bill Rieflin, Martin Atkins, Rey Washam, Max Brody, Joey Jordison and Roy Mayorga, keyboardist John Bechdel, and rappers and producers DJ Swamp and Arabian Prince.