Beware of the "Black Swan" fallacy. Deductive logic is tautological; there is no way to get a new truth out of it, and it manipulates false statements as readily as true ones. If you fail to remember this, it can trip you—with perfect logic. The designers of the earliest computers called this the "GIGO Law," i.e., "Garbage in, garbage out." Inductive logic is much more difficult—but can produce new truths.