A priori is a philosophical term that refers to knowledge, judgments, and principles which are true without verification or testing. It is something that is considered to be universally valid by default. In other words, the information and assumptions that a person starts with do not need to be verified with experience, but are, instead true. A a priori deals with knowledge that does not need to be verified. An example would be "All bachelors are unmarried." This is true naturally and by definition.