premise: Tyson, who served three years in jail for rape in the 1990s and who bit off part of Evander Holyfield's ear during a 1997 fight, still thinks he can be heavyweight champion again.
hypothesis: Tyson was out of jail by 1997.
reason: Tyson would have had to of been out of jail in 1997 in order to have bitten off the ear of Holyfield.