TY - JOUR T1 - Languages with self-reference I: Foundations JF - Artificial Intelligence Y1 - 1985 A1 - Perlis, Don AB - It is argued that a proper treatment of cognitive notions such as beliefs and concepts should allow broad and consistent expression of syntax and semantics, and that this in turn depends on self-reference. A theory of quotation and unquotation is presented to this end that appears to make unnecessary the usual hierarchical and non-first-order constructions for these notions. In the current paper (Part I) the underlying theory is presented; a sequel will treat in more detail the applications to cognition. VL - 25 SN - 0004-3702 UR - http://www.sciencedirect.com/science/article/pii/000437028590075X CP - 3 M3 - 16/0004-3702(85)90075-X ER -