Scientists are sometimes said to assume that something is not the case until there is proof that it is the case. Now suppose the question arises whether a given food additive is safe. At that point, it would be neither known to be safe nor known not to be safe. By the characterization above, scientists would assume the additive not to be safe because it has not been proven safe. But they would also assume it to be safe because it has not been proven otherwise. But no scientist could assume without contradiction that a given substance is both safe and not safe; so this characterization of scientists is clearly wrong. Which one of the following describes the technique of reasoning used above? ['A general statement is argued to be false by showing that it has deliberately been formulated to mislead.', 'A statement is shown to be false by showing that it directly contradicts a second statement that is taken to be true.', 'A statement is argued to be false by showing that taking it to be true leads to implausible consequences.', 'A general statement is shown to be uninformative by showing that there are as many specific instances in which it is false as there are instances in which it is true.']