 The points made so far suggest a solution to the surprise test paradox (Sorensen 1988, 328–343). As Binkley (1968) asserts, the test would be a surprise even if the teacher waited until the last day. Yet it can still be true that the teacher’s announcement is informative. At the beginning of the week, the students are justified in believing the teacher’s announcement that there will be a surprise test. This announcement is equivalent to: