  The early influence of philosophical logic on logic in AI was profound. The bibliography of  McCarthy &amp; Hayes 1969,  one of the most influential early papers in logical AI, illustrates the point well. There are 58 citations in the bibliography. Of these, 35 refer to the philosophical logic literature. (There are 17 computer science citations, one mathematical logic citation, one economics citation, and one psychology citation.) This paper was written at a time when there were hardly any references to logical AI in the computer science literature. Naturally, as logical AI has matured and developed as a branch of computer science, the proportion of cross-disciplinary citations has decreased. A sampling of articles from the first Knowledge Representation conference,  Brachman et al. 1989,  held in 1989, shows only 12 philosophical logic citations out of a total of 522 sampled citations; a sampling of articles from  Cohn et al. 1998,  held in 1998, shows 23 philosophical logic citations out of a total of 468 sampled.[7]