The big idea
Three words, three rules
AND joins two facts. Both must be true. "I have a brother AND a sister" → I have BOTH.
OR offers a choice. At least one must be true. "I have a brother OR a sister" → I have at least one (maybe both).
NOT flips a fact. "I have a brother NOT a sister" → brother is true, sister is false.
These three words are the building blocks of computer programs, court arguments, and rule systems. Mastering them lets you read fine print, write clear rules, and win debates.
- AND = both have to be true.
- OR = at least one has to be true.
- NOT = flips a fact to its opposite.