The general will is infallible; but the deliberations of the people are not necessarily so. The people may be, and often are, deceived. Particular interests may gain an advantage over general interests, and in that case the rival particular interests should be allowed to destroy each other, so that the true general interest may prevail. In order to secure the clear expression of the general will, there should be no parties or groups within the state; if such groups exist, they should be multiplied in number, so that no one party should get the upper hand. While, under the contract, each person alienates his power, his goods, and his liberty, he only alienates so much of these as are of concern to the community; but it belongs to the sovereign to determine what is of concern to the community and what is not. Whatsoever services a citizen owes to the state, he owes them directly the sovereign demands them; but the sovereign, on its part, must not charge its citizens with any obligations useless to the community; for, under the law of reason, nothing is done without cause, any more than under the law of nature. The general will, let it be repeated, tends always to public utility, and is intrinsically incapable of demanding services not useful to the public. A law is an expression of a general will, and must be general in its terms and import. The sovereign cannot legislate for part of the individuals composing the state, for if it did so the general will would enter into a particular relation with particular people, and that is contrary to its nature. The law may thus confer privileges, but must not name the persons to whom the privileges are to belong. It may establish a royal government, but must not nominate a king. Any function relating to an individual object does not appertain to the legislative power. As a popular assembly is not always enlightened, though the general will when properly ascertained, must be right--the service of a wise legislator is necessary to draw up laws with the sovereign's approval. The legislator, if he be truly wise, will not begin by writing down laws very good in the abstract, but will first look about to see whether the people for whom he intends them is capable of upholding them. He must bear in mind many considerations--the situation of the country--the nature of the soil--the density of the population--the national history, occupations, and aptitudes.