All knowledge begins with experience. Entitled Pure when there is no admixture of anything empirical. A proposition which is thought of as necessary is a priori . If it is not derived from any proposition except on which also has the validity of a necessary judgment, it is an absolutely a priori judgment. A proposition which is thought of as universal is a priori .
Empirical universality is only arbitrary.
Certain modes of knowledge leave the field of all possible experience and have the appearance of extending the scope of our judgments beyond the limits of experience. The unavoidable problems of pure reason are God, freedom and immortality. Mathematics is an example of how far, independently of experience, we can progress in a priori knowledge. Those in which the connection is thought without identity. Judgments of experience are all synthetic.