Most current theories of meaning and mental content accept externalism. One of its forceful exponents is Ruth Garrett Millikan. She argues that externalism leads to the abandonment of "the last myth of the given", that is, of the idea that identity of meaning and mental content is somehow unproblematically given to us, and that we can easily recognize the sameness of meaning and mental content. If one refuses such a "mythical" giveness or meaning rationalism, one has to admit that there is no logical possibility known a priori . The paper tries to show that even if one abandons meaning rationalism one can still hold that there are logical possibilities known a priori . The claim is defended by arguing that a priori knowledge is not completely independent from experience and does not demand the absolute transparency of meaning from the first-person point of view. A priori knowledge requires only a priori justification, that is, such a justification that is based merely on relations between meanings or contents.