Perhaps the most promising conception of protophenomenal properties is given by the view Herbert Feigl (1960) called “panqualityism”, crediting it to a conversation with Stephen C. Pepper. Versions of the view itself were held by William James (1904), Ernst Mach (1886), Bertrand Russell (1921), David Armstrong (1961), and Peter Unger (1999). More recently the view has been prominently defended by Sam Coleman (2012, 2014, 2015, 2016). According to panqualityism the protophenomenal properties are unexperienced qualities. Our conscious experience is filled with experienced qualities, e.g., those phenomenal qualities involved in seeing colour or feeling pain. Panqualityists believe that such qualities are only contingently experienced, and that in basic matter they exist unexperienced.