 Experience never gives its judgments true or strict, but merely assumed or comparative universality (through induction), so that, properly speaking, it must be formulated: so far as we have observed until now, no exception has been found to this or that rule. If, therefore, a judgment is thought with strict universality, i.e., so that no exception at all is allowed to be possible, then it is not derived from experience, but is valid absolutely a priori. Empirical universality is thus only an arbitrary augmentation of validity from that which is valid in most cases to that which is valid in all—as, e.g., in the proposition: all bodies are heavy. By contrast, where strict universality essentially belongs to a judgment, this [universality] indicates a special source of cognition for [the judgment], namely a faculty of a priori cognition. Necessity and strict universality are thus secure criteria of an a priori cognition, and also inseparably belong together.