John Locke makes an argument for majority rule in Sections 95-99 of John Locke's 2d Treatise on Government: “Of Civil Government” (in Chapter VIII, "Of the Beginning of Political Societies"). His main argument is that some decision-making procedure must be binding on every member of a civil society, otherwise it cannot function as any improvement over the state of nature. That argument does not point specifically to majority rule. However, I think he is right in something he does not say explicitly, but is relying on: simple majority rule is the default rule humans tend to revert to in cases where everyone in a group is considered equal. This points to the key desideratum for a decision-making rule binding on those in a civil society: respecting the equality of individuals within that society. Technically, the decision-making rule should be symmetric in how it treats every individual.
Social choice mechanisms different from majority rule, but obeying the equality criterion are a research interest of mine. Here are ungated versions of my papers on this topic and a links to a blog post on an early stage project of ours in this area:
- Aggregating Local Preferences to Guide Marginal Policy Adjustments, by Dan Benjamin, Ori Heffetz, Miles Kimball and Nichole Szembrot
- The Relationship Between the Normalized Gradient Addition Mechanism and Quadratic Voting, by Dan Benjamin, Ori Heffetz, Miles Kimball and Derek Lougee (video of my presentation on this here)
- Dan Benjamin, Ori Heffetz and Miles Kimball—Repairing Democracy: We Can’t All Get What We Want, But Can We Avoid Getting What Most of Us *Really* Don’t Want?
Dan Benjamin, Gabriel Carroll, Ori Heffetz, Derek Lougee and I have also been working hard on the math for dynamic versions of the "normalized gradient addition" social choice mechanism.
Contrary to John Locke's drift, I think it is possible to do much, much better than majority voting as a social choice mechanism. Part of the standard training of economists is Arrow's Impossibility Theorem, which I will briefly summarize as an ironclad proof that "No social choice mechanism is perfect." But I urge you to take John Locke's argument in sections 95-99 of his 2d Treatise as a strong argument that we need some social choice mechanism binding on all members of a civil society:
§. 95. MEN being, as has been said, by nature, all free, equal, and independent, no one can be put out of this estate, and subjected to the political power of another, without his own consent. The only way whereby any one divests himself of his natural liberty, and puts on the bonds of civil society, is by agreeing with other men to join and unite into a community, for their comfortable, safe and peaceable living one amongst another, in a secure enjoyment of their properties, and a greater security against any, that are not of it. This any number of men may do, because it injures not the freedom of the rest; they are left as they were in the liberty of the state of nature. When any number of men have so consented to make one community or government, they are thereby presently incorporated, and make one body politic, wherein the majority have a right to act and conclude the rest.
§. 96. For when any number of men have, by the consent of every individual, made a community, they have thereby made that community one body, with a power to act as one body, which is only by the will and determination of the majority: for that which acts any community, being only the consent of the individuals of it, and it being necessary to that which is one body to move one way; it is necessary the body should move that way whither the greater force carries it, which is the consent of the majority: or else it is impossible it should act or continue one body, one community, which the consent of every individual that united into it, agreed that it should; and so every one is bound by that consent to be concluded by the majority. And therefore we see, that in assemblies, empowered to act by positive laws, where no number is set by that positive law which empowers them, the act of the majority passes for the act of the whole, and of course determines, as having by the law of nature and reason, the power of the whole.
§. 97. And thus every man, by consenting with others to make one body politic under one government, puts himself under an obligation to every one of that society, to submit to the determination of the majority, and to be concluded by it; or else this original compact, whereby he with others incorporates into one society, would signify nothing, and be no compact, if he be left free, and under no other ties than he was in before in the state of nature. For what appearance would there be of any compact? what new engagement if he were no farther tied by any decrees of the society, than he himself thought fit, and did actually consent to? This would be still as great a liberty, as he himself had before his compact, or any one else in the state of nature hath, who may submit himself, and consent to any acts of it if he thinks fit.
§. 98. For if the consent of the majority shall not, in reason, be received as the act of the whole, and conclude every individual; nothing but the consent of every individual can make any thing to be the act of the whole: but such a consent is next to impossible ever to be had, if we consider the infirmities of health, and avocations of business, which in a number, though much less than that of a commonwealth, will necessarily keep many away from the public assembly. To which if we add the variety of opinions, and contrariety of interests, which unavoidably happen in all collections of men, the coming into society upon such terms would be only like Cato’s coming into the theatre, only to go out again. Such a constitution as this would make the mighty Leviathan of a shorter duration, than the feeblest creatures, and not let it outlast the day it was born in: which cannot be supposed, till we can think, that rational creatures should desire and constitute societies only to be dissolved: for where the majority cannot conclude the rest, there they cannot act as one body, and consequently will be immediately dissolved again.
§. 99. Whosoever therefore out of a state of nature unite into a community, must be understood to give up all the power, necessary to the ends for which they unite into society, to the majority of the community, unless they expressly agreed in any number greater than the majority. And this is done by barely agreeing to unite into one political society, which is all the compact that is, or needs be, between the individuals, that enter into, or make up a commonwealth. And thus that, which begins and actually constitutes any political society, is nothing but the consent of any number of freemen capable of a majority to unite and incorporate into such a society. And this is that, and that only, which did, or could give beginning to any lawful government in the world.
In practice, we use majority voting of some description as our go-to social choice mechanism. The standard for an alternative social choice mechanisms is not that they are perfect—that is provably impossible; the standard is that it is better than the current system, which is heavily reliant on majority voting. Social Choice should be—and is—a vibrant, active area of research.
Note 1: When I claimed above that majority voting is the default rule in situations where everyone is considered equal, I am using the "Boy Scout test" I used for another principle in "John Locke: Property in the State of Nature." Kids, left to their own devices, often use majority rule. It is hard to know how much this owed to the culture we live in. But I suspect it goes way back.
Note 2: When more than one candidate is running for an office, majority voting is often impossible because no candidate has gotten a majority. The rule there is often to choose the candidate with the most votes even if that is far short of a majority. Another common alternative is to have a runoff between the top two vote getters. Vermont has instituted ranked-choice voting, an interesting system, but one I think is still inferior to the one we suggest in "Repairing Democracy: We Can’t All Get What We Want, But Can We Avoid Getting What Most of Us *Really* Don’t Want?"
For links to other John Locke posts, see these John Locke aggregator posts: