 The SEP editors would like to thank Fraser MacBride for helping us to organize the team of coauthors who contributed sections to this entry. We note their contribution and acknowledgments as follows. Section 1 (“Life and Work”) is by F. MacBride, who thanks Gary Kemp and Sam Lebens; Section 2 (“The Foundations of Logic and Mathematics”) is by M. Marion, who thanks Cheryl Misak and Jan von Plato for discussions related to his section; Section 3 (“Ontology”) is by F. MacBride, who thanks Frederique Janssen-Lauret, Cheryl Misak, Kevin Mulligan and Thomas Uebel; Section 4 (“Belief and Truth”) is by M. Frápolli; Section 5 (“Conditionals”) is by D. Edgington; Section 6 (“Partial Belief and Subjective Probability”) is by E. Elliott; Section 7 (“Laws and Theories”) is by S. Lutz; and Section 8 (“Contributions to Mathematics”) is by J. Paris. 