Terminology Tuesday: Rational
Quality of belief or action that is in accord with reason. There are many different forms of rationality. A person is deontologically rational when that person has fulfilled his or her rational obligations or duties (whatever those may be). In this sense, a person may be rational to hold a false belief so long as the person has good reasons for the belief or has not violated any duties in forming it. Another sense of rationality relates to truth. In this sense we may say that a belief-forming practice is rational if it is likely to result in a true belief.
Evans, C. S. (2002). Pocket Dictionary of Apologetics & Philosophy of Religion. Downers Grove, IL: InterVarsity Press.