"Synthetic a priori proposition, in logic, a proposition the predicate of which is not logically or analytically contained in the subject—i.e., synthetic—and the truth of which is verifiable independently of experience—i.e., a priori".

"In general the truth or falsity of synthetic statements is proved only by whether or not they conform to the way the world is and not by virtue of the meaning of the words they contain. Synthetic a priori knowledge is central to the thought of Immanuel Kant, who argued that some such a priori concepts are presupposed by the very possibility of experience''.