Four-valued logic

Four-valued logic is a system of thinking that includes four possible outcomes instead of the two outcomes (true/false or yes/no) that we normally use. Think of it like a four-sided dice. Instead of just rolling a 1 or a 2 (yes/no or true/false) you can also roll a 3 or a 4. 3 and 4 represent two other possible outcomes. This can be useful when you want to make a decision with four options.