15. If any one asks how the State and the civil power is of God any otherwise than the railway company with its power, or even the fever with its virulence, a moment's reflection will reveal the answer in the facts, that railway communication, however convenient, is not an essential feature of human life, as the State is: while diseases are not requirements in order to good, but incidental defects and evils of nature, permitted by God. Why God leaves man to cope with such evils, is not the question here. _Readings_.--Ar., _Pol_., I., ii.; III., i.; III., ix.: nn. 5-15. SECTION IV.--_Of the Variety of Polities_. 1. _One polity alone is against the natural law; that is every polity which proves itself unworkable and inefficient: for the rest, various States exhibit various polities workable and lawful, partly from the circumstances, partly from the choice, of the citizens: but the sum total of civil power is a constant quantity, the same for all States_. We proceed to establish the clauses of this statement in succession. 2. If a watch be necessary to a railway guard, and he is bound to have one accordingly, it is also necessary, and he is bound to procure it, that the watch shall go and keep time. A watch that will not keep time is an unlawful article for him to depend upon, being tantamount to no watch, whereas he is bound to have a watch. Otherwise, be his watch large or small, gold, silver, or pinchbeck, all this is indifferent, so long as it be a reliable timekeeper. In like manner, we must have a State, we must have a government, and we must have a government that can govern. Monarchy, aristocracy, parliaments, wide or narrow franchise, centralisation, decentralisation, any one of these and countless other forms--apart from the means whereby it is set up--is a lawful government, where it is a workable one; unlawful, and forbidden by God and nature, where it cannot work. A form of government that from its own intrinsic defects could nowhere work, would be everywhere and always unlawful.