 The critical method, on the other hand, begins with the assumption that there are universal, absolute values which all subjects ought to recognize and conform to. It postulates a “normal consciousness whose principles must be recognized, insofar as anything at all is to have universal validity” (Windelband 1883: 280). This normal  consciousness,[18]  inasmuch as it embodies a norm, is not an empirically real subject and cannot be investigated using the genetic method. The “axioms”, which form the subject matter of philosophy, are the principles that must have normative force if there is to be a normal consciousness at all. These axioms are “means to the end of universal validity” (1883: 281)—they are the norms that must be recognized if there are to be any universally valid norms at all. For example, there could be a normal consciousness in a world where ripe tomatoes are blue and not red. Thus the norm “Believe that ripe tomatoes are red”, though it is true and thus universally valid in our world, is not an axiom—not a norm whose recognition is a precondition of universal validity. The law of contradiction, on the other hand, is a precondition of universal validity. No matter what color ripe tomatoes are in our world, there would be no point in adopting the norm “Believe that ripe tomatoes are red” as a norm of truth, unless we also recognize the demand to avoid contradictions. The proof that these axioms are the indispensable preconditions of universal validity cannot be empirical, as the genetic method would require.