Now, this principle of morality, precisely on account of the universality of the legislation that makes it the formal supreme determining basis of the will regardless of all subjective differences of the will among individuals is declared by reason at the same time to be a law for all rational beings insofar as they have a will at all,.e., a pow to determine their causality by the presentation of rules, hence insofar as they are capable of performing actions according to principl and consequently also according to practical a priori principles (for these alone have that necessity which reason demands for a principle).