Aristotle said: "To say of what is that it is not, or of what is not that it is, is false, while to say of what is that it is, and of what is not that it is not, is true." However, a statement may be about how things once were; this would be a true statement if it is clear that it is not a statement about how things are now. Most often, the tense of the verb will indicate this, but there may be other ways in which the statement is qualified: for example, by saying when the statement was true.