KEENER ON QUASI-CONTRACTS, 481. rather than another. It might prescribe one standard of conduct to-day, and another to-morrow, and a third the day after. Being without a reason in fact, it would necessarily violate all reasons, and would literally be unreasonable. Unreasonableness, however, is irrationality ; and municipal law, therefore, not being irrational, must be founded upon a reason. Any definition which neglects to indicate this is, so far at least, defective. Every juridical inquiry which purports to be exhaustive and rationally sufficient must, in view of the foregoing considerations, be pressed back to the ultimate reasons of law. Of course, any such requirement may be urged beyond legitimate bounds. A demand for ultimate reasons continually pressed would not stop short of the foundations of the universe, and would include the most recondite investigations of philosophy. This, however, is obviously unnecessary in anything but philosophy, and therefore jurisprudence, like all other special sciences, may with propriety rest upon assumed postulates. All that can be rightfully de- manded is that its postulates be clearly expressed as postulates, and that they do not illicitly contain a predetermination of its conclusions. These conditions being complied with, any investi- gation into the postulates themselves will lie outside of law, and will properly belong with that investigation which relates to the postulates of science generally, that is, philosophy. One of the postulates of jurisprudence has been already indi- cated. Being a science, and law, as its subject matter, being therefore rational, its determinations must be ascertained by the process of reason and must endure the tests of logic. The validity of the syllogism in matters juridical, as the antecedent condition of any possible juridical argument, is thus the first postulate of jurisprudence. Another involves the mooted question of the freedom of the will. A standard of human conduct, as distinguished from neces- sary laws like those of mechanics, implies the possibility, together of course with the impropriety, of disobedience, and therefore of necessity implies the ability of the human being to whom the rule is prescribed to choose in the alternative between obedience and disobedience. That ability to choose is freedom, and the posses- sion of it under the prescription of law is juridical responsibility. Freedom in the individual as the antecedent condition of juridical responsibility is thus a second postulate of jurisprudence. 64
