A Priori vs A Posteriori Reasoning: Express

I. A Posteriori

Knowledge gained by observing the world. You would have to go out in the world to gain this type of knowledge. "Elephants have large ears", or "Jupiter has a giant red storm."

II. A Priori

Knowledge gained by reasoning, not by observing the world. Mathematical knowledge, such as that 2 + 2 = 4. Or knowledge of logical structure, like "If A then B, A, therefore B". Or knowledge of tautologies, such as "All bachelors are unmarried."