ABSTRACT
A priori knowledge is knowledge of propositions that do not require (sense) experience to be known to be true. Knowledge that can be established only through experience is a posteriori. The a priori-a posteriori distinction is about how to check or establish knowledge. It is not about how we acquire the concepts or words of the proposition. Babies are not born knowing that all bachelors are unmarried! Yet this is a truth that clearly doesn’t need testing against experience: we know it is true just by knowing what it means. Of course, we first have to learn what it means, but that is a different issue from how we check if it is true.
