  The statements the Stranger considers, “Man learns,”  “Theaetetus is sitting,” and “Theaetetus is  flying,” are all positive predications, the first two true, the third false. But as noted above (§ 5.5), we need negative  predication to analyze the false statement, “Theaetetus is  flying.” Since the statement is false, the statement  “Theaetetus is not flying” is true.