  There is a growing body of literature on truthmaker theory; see for example: Russell 1918; Mullligan, Simons, and Smith 1984; Fox 1987; Armstrong 1997, 2004; Merricks 2007; and the essays in Beebe and Dodd 2005; Monnoyer 2007; and in Lowe and Rami 2009. See also the entry on truthmakers in this encyclopedia.