The Declaration of Reasonable Doubt is an Internet signing petition which seeks to enlist broad public support for the Shakespeare authorship question to be accepted as a legitimate field of academic inquiry. The petition was presented to William Leahy of Brunel University by the actors Derek Jacobi and Mark Rylance on 8 September 2007 in Chichester, England, after the final matinee of the play I Am Shakespeare on the topic of the bard's identity, featuring Rylance in the title role. As of 23 April 2016, the 400th anniversary of Shakespeare's death and the original self-imposed deadline, the document had been signed by 3,348 people, including 573 self-described current and former academics. As of December 2022, the count stood at 5,128 total signatures.
The declaration has been met by scepticism from academic Shakespeareans and literary critics. For the most part, they disparage the idea that Shakespeare is a pseudonym for one or more individuals who wrote the works attributed to him and characterise the doubt as an exercise in the logical fallacies of argumentum ad populum (appeal to popularity or the appeal to numbers) and argument from false authority.
The declaration has been signed by prominent public figures, including U.S. Supreme Court Justices John Paul Stevens and Sandra Day O'Connor, in staged signing events followed by press releases in order to gain publicity for the goal of the petition.
Doubters claimed in the declaration
The declaration named twenty prominent figures from the 19th and 20th centuries who the coalition claim were doubters: