 The original version of this article, entitled “Replication”, was written by the late David Hull. In January 2005, John Wilkins became a co-author, with the responsibility for revising and updating the entry, so as to keep it current. Thus, revisions on or after January 2005 were introduced by Wilkins and, from October 2018, by Wilkins and Pierrick Bourrat. Although the current version includes some of Hull’s original essay, it does not represent his final views.