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."
Robert Heinlein, "Time Enough For Love"