1. A method, in a data processing system comprising a processor and a memory configured to implement a question and answer system (QA), for providing confidence rankings based on temporal semantics, the method comprising: responsive to receiving an input question, identifying a set of candidate answers from a knowledge domain based on a correlation between an identified one or more predicates and an identified one or more arguments to the knowledge domain; associating a confidence score with each of the candidate answers; refining each confidence score associated with each candidate answer based on a set of temporal characteristics identified in the input question, wherein each confidence score is refined based on the set of temporal characteristics using a temporal confidence function computed against a temporal interval between a reference time of the question and a respective reference time associated with the set of candidate answers; and providing a set of temporally refined candidate answers to the user.