Double negation

Double negation

The law of double negation states that the negation of a negation returns the original proposition.

Statement

• ¬(¬p) ≡ p

Explanation

If it is not the case that p is false, then p must be true. This allows simplification of expressions with two consecutive negations.

Example

• "It is not true that it is not raining" is equivalent to "It is raining".
• In Python: not (not p) evaluates to the same as p.

Truth Table

p	¬p	¬(¬p)
T	F	T
F	T	F