In classical logic, the universal negative is one of the four types of categorical proposition. The universal negative states that no member of a class is a member of another given class. In other words, *No X are Y*.

No monkeys eat soy.

No noders are neurotic.

The universal negative also implies its converse. From the examples above, we know that nothing that eats soy is a monkey and nobody who is neurotic nodes.

The rule *You cannot prove a universal negative *is sometimes invoked against atheists, but this is false (as well as being a universal negative itself!). Provable universal negatives include