Paradox is a situation or statement which seems difficult to understand because it contains two opposite facts or characteristics. Example: "This statement is false." If you think it's true, then it must be false, but if you think it's false, it must be true. Now, that's a paradox! "I always lie" is a paradox because if it is true it must be false Contradiction: when something is the complete opposite of something else or very different from something else, so that one of them must be wrong Example: You say that you're good friends and yet you don't trust him. Isn't that a bit of a contradiction?

I would use paradox when I'm considering (philosophical) questions that I need to think about. Contradiction is more common for things that happen every day.