Rationalism differentiates between a priori and a posteriori knowledge defined often as "independent/dependent of experience" and as a property of the object of knowledge, such as "analytic" and "necessary", which are not depends on subjective perspective (they are the same for all subjects).
However, taking for example the stick example of Kripke, we found that "The stick is one meter long" is a priori for the person which established this length unity (a prescriptive act of baptism "We will call 'meter' to the length of this iron stick), and a posteriori for the rest, which must to know or test if actually this stick is the standard unity of length (for example, looking for in books about history of science).
Moreover, for example the Morgan's Laws can be known a posteriori for somebody which is constructing a truth-table in order to be sure that it is a tautology, but a priori for which is making a demonstration making use of this equivalence without questioning its true.
What do you think?