Rethinking the Social Contract (1): On the Concept of Convention in Hume and Rousseau

[Abstract]

Introduction

In contemporary society, we are constantly confronted with various claims to “rights.”
What is particularly striking is that rights have a peculiar character: even without any explicit agreement or contract, one can nonetheless unilaterally demand action or inaction from others — or, more directly, issue commands. (This point will be examined in detail later.)

Historically, in the West, absolute monarchs issued such unilateral commands to commoners, justified under the doctrine of the divine right of kings.
But in the age of civil society, where all citizens are presumed equal, a new problem arises: How can one citizen suddenly declare to another — with whom they have made no contract — “This is my right,” and demand compliance? What, then, is the legitimate basis for such authority?

The Scottish philosopher David Hume (1711–76) sought to ground the foundation of rights and order not in divine law or abstract reason, but in convention: socially shared and self-evident practices that arise not from deliberate reasoning, but from intuitive and spontaneous patterns of human judgment.
According to Hume, because human cognition is held in common, certain forms of self-evidence spontaneously emerge as social conventions. The legitimacy of demanding that others comply with such conventions constitutes the very foundation of what we call rights.

Now, the term convention also appears in the work of Hume's contemporary, Jean-Jacques Rousseau (1712–78), in The Social Contract (1762).
According to my reading, Hume and Rousseau share a structurally similar stance toward convention. In fact, reading their respective concepts of convention in relation to one another may help render Rousseau’s notoriously difficult Social Contract more coherent.

Hume did not adopt contractarian theories of society based on promise — that is, theories that define society through explicit agreements among autonomous individuals. In my view, Rousseau, too, belongs in this camp. Both thinkers regarded spontaneous, tacit convention — not explicit agreement — as the foundation of a free society where no one is subject to the arbitrary will(*1) of another.

To substantiate this claim, let us begin by examining Hume’s account of convention — the foundation upon which his conception of justice and rights is built.

What Is Convention?

⚠️ This section is the core of the present essay. Please proceed as carefully and attentively as possible.

In §3.2.2 of A Treatise of Human Nature, Hume presents his account of “the origin of justice and property.” What follows is not a direct summary of Hume’s text, but an attempt to explain — in my own words — what he is trying to convey.

At some point, when humans still lived as primitives, we began to form small groups and hunt cooperatively.
When it came time to divide the catch, they must have learned to distribute it in a way that avoided conflict — that is, artificially but skillfully.
The methods of distribution that emerged would have been those guided by intuitive and spontaneous patterns of human judgment — patterns perceived by all as fair or self-evident, arising from an intuitive alignment of judgment (Übereinstimmung; see Note below).

Note: This alignment of judgment is not the same as an agreement or promise.

The phrase alignment of judgment here is similar to what Wittgenstein called Übereinstimmung. Übereinstimmung is not something reached through negotiation or reasoning, but rather something people follow intuitively — often without even realizing they are doing so.

For example, suppose that five primitive humans cooperated to catch ten fish. They would likely have divided them [2,2,2,2,2]. That, in this case, would have been the self-evident distribution — a division that no one questioned.
We will refer to this unquestioned state — in which nothing appears out of place to anyone — as “alignment of judgment (Übereinstimmung)”.

To avoid the misunderstanding that such alignment is simply a matter of numerical division, let us consider a more complex case. Suppose that these same people transitioned from a hunting society to an agricultural one. In that case, a distribution like [6,1,1,1,1] may have become the new “self-evident” pattern — where the “6” corresponds to the village leader. Even here, no one questions the distribution.

The key point here is that in all such cases, the distribution arises not from deliberation or explicit agreement, but from the intuitive structure of human cognition — a spontaneous and tacit alignment, not something consciously constructed. It is perceived as so evidently appropriate that there is no need for discussion or negotiation. This is what constitutes an alignment of judgment(Übereinstimmung), not an agreement or promise.

Footnote: The phrase alignment of judgment (Übereinstimmung) is borrowed from Wittgenstein’s notion of “language games.” For further exploration of this concept, see: Wittgenstein’s Paradox — The Ultimate Foundation of the World. (*written in Japanese)

Once an “evident share” is established through alignment of judgment, an additional intuition arises just as spontaneously: that it would be wrong to take what belongs to someone else. This feeling, too, is a product of human logic — or, more precisely, of the internal structure of human cognition — and arises spontaneously from the same alignment of judgment.

Hume regarded this very process of alignment as the mechanism by which the concepts we now call justice and property come into being. These concepts do not preexist human interaction as abstract ideas. Rather, they emerge not as theoretical constructs but as practical forms of mutual acknowledgment — products of recurring patterns of human behavior.

After this convention, concerning abstinence from the possessions of others, is entered into, and every one has acquired a stability in his possessions, there immediately arise the ideas of justice and injustice; as also those of property, right, and obligation. The latter are altogether unintelligible without first understanding the former. Our property is nothing but those goods, whose constant possession is established by the laws of society; that is, by the laws of justice. Those, therefore, who make use of the words property, or right, or obligation, before they have explained the origin of justice, or even make use of them in that explication, are guilty of a very gross fallacy, and can never reason upon any solid foundation.（§3.2.2）

No one can doubt, that the convention for the distinction of property, and for the stability of possession, is of all circumstances the most necessary to the establishment of human society, and that after the agreement for the fixing and observing of this rule, there remains little or nothing to be done towards settling a perfect harmony and concord.（§3.2.2）

The convention referred to here is not the result of deliberate agreement, but rather a self-evident alignment of judgment (Übereinstimmung) that arises spontaneously from the intuitive structure of human cognition. Precisely because it is self-evident, all members of the group feel internally bound by the rule. This is why, as Hume writes, “there remains little or nothing to be done towards settling a perfect harmony and concord.”

Over time, this self-evidence takes root within the group as what Hume calls human conventions — that is, socially embedded forms of practical understanding. And it is precisely the mutual adherence to such tacitly shared conventions that, in Hume’s view, constitutes the origin of human order — and of rights themselves.

This is why one can validly say to another, “Don’t touch my share”: the other already intuitively feels it as yours. The legitimacy of such an instruction — or right — lies in its being mutually felt, intuitively acknowledged by all, rather than unilaterally imposed. The binding force of rights does not derive from conscious contract or agreement, but from convention — from the tacit alignment of judgment shared by all members of the society.

(Supplement) Hume as an Anti-Modernist

Although it diverges slightly from the main thread of this essay, let me briefly outline Hume’s basic philosophical orientation. If I were to summarize it in a single phrase, I would say that Hume was an anti-modernist.

By “modernism” here, I mean the view that human beings are autonomous and rational subjects — the starting point of the world — and that, by applying reason to understand and act upon the world, they can bring about social progress. In political theory, this view — what might be called social atomism — underlies the idea that society is formed through contracts: explicit agreements made by rational individuals pursuing mutual benefit.

The phrase “social contract” typically evokes this model — a society built upon promises, that is, explicitly constructed agreements among autonomous individuals. But Hume rejected this kind of contractarian theory grounded in rational individualism.

As we shall see later, Hume argued that for a promise to carry real binding force, it must rest upon a prior convention — a framework of shared expectations that arises spontaneously and tacitly from human interaction. In his view, the true foundation of social order lies not in the promise itself, but in the underlying convention: not something consciously constructed, but something that emerges from the alignment of human judgment (Übereinstimmung).

The Difference Between Convention and Promise

It is important to note that Hume draws a sharp distinction between convention and promise, emphasizing that the two differ fundamentally in kind.

This convention is not of the nature of a promise: For even promises themselves, as we shall see afterwards, arise from human conventions. It is only a general sense of common interest; which sense all the members of the society express to one another, and which induces them to regulate their conduct by certain rules. （§3.2.2）

But as there is naturally no inclination to observe promises, distinct from a sense of their obligation; it follows, that fidelity is no natural virtue, and that promises have no force, antecedent to human conventions. （§3.2.5）

The second quotation may appear difficult at first glance, but its meaning is this:
The obligation to keep a promise does not stem from the promise itself, but from the underlying convention that gives it meaning. Only when a convention is already in place as a matter of social fact does a sentiment — or tendency — to honor promises arise. There is no natural (or spontaneous) feeling of “I must keep this promise” that emerges from the promise alone. In Hume’s terms, fidelity is not a natural virtue. Promise has no binding force prior to the existence of human conventions.

In short, a promise may exist in form without convention, but it lacks substantive force — it cannot bind without a shared framework of judgment. This distinction is of great importance.

As we saw in the example of distribution among primitive humans, the concept of property arises from a shared sensibility — a kind of mutual acknowledgment grounded in human judgment. Once this common recognition is socially established, it becomes the basis of convention. Only when such a convention is in place does it become meaningful to define something as “property,” or to promise to respect it. It is precisely because this process has taken place that we feel compelled to honor such promises. Without convention, a promise cannot function as an independent force. Severed from the framework of shared judgment, a promise becomes unintelligible.

Let us consider one more simple example to clarify the relationship between convention and promise.

The Basis of Rights

A. Rights as given by God to human beings, who are obliged to live according to divine will. (theological theory)
B. Rights as rationally invented through logical reasoning. (modernist theory)
C. Rights as discovered through human practices — as human convention. (Hume / anti-modernist view)

Consider, for instance, the right in modern society to receive child support payments from a divorced spouse. Why does such a right exist? Because it has been discovered through human practice and reflection, and because this awareness is socially shared as a common interest. That is, everyone’s judgment spontaneously (or intuitively) aligns on this point.

By contrast, the claim “I have a right to receive 100,000 yen each month from a complete stranger” is unintelligible. Such a notion does not spontaneously arise within human judgment, and therefore cannot be shared as a common interest.

In this way, both the right to child support and the right of property are discovered through shared human sensibility. They are felt as self-evident and thereby become solidified as convention. It is this transformation into convention that makes it legitimate to establish such rights as “law” — that is, to formally promise them as binding obligations.

(The point here is that the basis for rights such as child support or property lies not in A — divine authority — nor in B — rational invention — but in C: the human convention discovered through social practice.)

As noted at the outset, rights possess a peculiar quality: they allow one to demand action or inaction from others. The right of property, for instance, is the right to demand non-interference — “Don’t touch what is mine.” But why can such demands be made?

According to Hume, it is because they are felt as self-evident — not unilaterally imposed, but mutually acknowledged. A right, in essence, consists in the legitimacy demanding conformity to what is recognized as self-evident — something tacitly and intuitively shared among members of society.

Rights that are disconnected from this shared structure of judgment and self-evidence cannot meaningfully exist.

The Principle of Authority and Loyalty

Why do we pledge loyalty to someone? It is likely because we perceive in them some form of psychological legitimacy — whether it be military strength, divine lineage, or material generosity (such as the granting of land). To obey a command perceived as legitimate is part of human judgment. Such obedience rests on a convention that is spontaneous — or voluntary — by its very nature. But once that sense of legitimacy disappears, the convention itself dissolves.

Government, therefore, arises from the same voluntary conversation of men; and it is evident, that the same convention, which establishes government, will also determine the persons who are to govern, and will remove all doubt and ambiguity in this particular. And the voluntary consent of men must here have the greater efficacy, ...（§3.2.10）

On this point, Rousseau argues in The Social Contract (§1.4) that “when the vanquished obey the victor in war, this is not a convention — it is slavery.” In short, this is not the kind of voluntary adherence to convention that Hume had in mind. ……We will return to the significance of this distinction on the next page.

Grotius and others derive the supposed right of slavery from war. The victor, they say, has the right to kill the vanquished; therefore, the vanquished may redeem his life at the cost of his freedom — a convention all the more legitimate because it benefits both parties. (The Social Contract(SC), §1.4)

Whether between one man and another, or between one man and a people, such a proposition is always equally absurd: “I make with you a convention that is entirely to your detriment and entirely to my advantage, which I shall observe for as long as I please, and which you shall observe for as long as I please.” (SC, §1.4)

For as soon as force makes right (droit), the effect changes with the cause. (...) But what sort of right perishes when the force ceases? If one must obey by force, there is no need to obey out of duty; and if one is no longer forced to obey, one is no longer obliged. Thus, the word “right” adds nothing to force; here, it means nothing at all. (...) Let us agree, then, that force does not make right, and that one is obliged to obey only legitimate powers. My original question therefore remains. (SC, §1.3)

(Related essay)
Avoiding the Tyranny of the Majority: The Role of Convention in Rousseau’s Social Contract

(Aside: On the Resemblance Between Convention and Language Games)

Those familiar with Wittgenstein’s theory of language games may have noticed a resemblance between convention and what he calls “rules.”(*2) Indeed, certain passages in Hume suggest a mode of thinking that closely anticipates the language-game perspective.

Two men, who pull the oars of a boat, do it by an agreement or convention, though they have never given promises to each other. Nor is the rule concerning the stability of possession the less derived from human conventions, that it arises gradually, and acquires force by a slow progression, and by our repeated experience of the inconveniences of transgressing it. On the contrary, this experience assures us still more, that the sense of interest has become common to all our fellows, and gives us a confidence of the future regularity of their conduct: And it is only on the expectation of this, that our moderation and abstinence are founded. In like manner are languages gradually established by human conventions without any promise.（§3.2.2）

Rousseau’s Use of Convention

On the next page, we will examine Rousseau’s concept of the general will in detail, but first, let us briefly review his use of the term convention here.

At the beginning of The Social Contract, Rousseau uses convention in several key formulations:

(*Note: The following are paraphrased representations — not direct quotations — from each section.)

Social order and rights are based on conventions. (The Social Contract, §1.1)

Even familial relationships among humans are maintained only through convention. (SC, §1.2)

Since no person has natural authority over others, and since force can never generate right, the only foundation of all legitimate authority among human beings is convention. (SC, §1.4)

The terms of the social contract may never have been formally declared, but they are everywhere the same and everywhere tacitly accepted and affirmed. Once this contract is broken, one loses liberté conventionnelle and reverts to liberté naturelle — the natural liberty of man in the Hobbesian state of nature. (SC, §1.6)

The term liberté conventionnelle is sometimes understood as “freedom by contract.” Let us conclude this section by clarifying what conventionnelle means in the context of Rousseau.

You sometimes hear news reports like this:
“A bear was sighted in XX Village. It broke into a house, stole food from the refrigerator, and fled.”

Naturally, the bear does not suffer pangs of guilt. This is because it has no conception of property — it simply follows instinct.

In this sense, Gian in the state of nature (*3) is just like the bear: governed by animal impulse, acting without any sense of social constraint. *4

By contrast, Gian in the social state has internalized a human convention: the idea that property belongs to the first occupant.
He spontaneously falls into the assumption that the marble Nobita found in the vacant lot (by first claiming it) now belongs to Nobita. (Once one enters the social state, and a convention such as “property arises from first occupancy” has taken root, it becomes impossible to erase that idea from one’s mind.)

Thus, even when Gian in the social state wants to take the marble, he inevitably experiences a moment of hesitation — not one based on rational calculation of legality, but a purely intuitive response.
And because of this ingrained assumption, even if he does take it — by force, that is — he may later return it. (The Gian in the state of nature would not even have the idea of returning it.)

When imprisoned, the natural Gian has no idea why he has been captured and experiences the situation as absurd or unintelligible. But the social Gian, even without explicit reasoning about law or legality, intuitively accepts his arrest — not as a logical conclusion, but as something obvious and self-evident.

The social Gian is internally and cognitively bound by human conventions. As a result, Nobita can live in peace — that is, with enhanced safety.

……This is what Rousseau calls liberté conventionnelle — “freedom by convention.” (not by contract)

This transition from the state of nature to the civil state produces a very remarkable change in man: it substitutes justice for instinct in his conduct, and gives to his actions a moral character that they previously lacked. (The Social Contract(SC), §1.8)

Far from destroying natural equality, the fundamental pact, on the contrary, substitutes a moral and legitimate equality for whatever physical inequality nature may have placed among men. Thus, though they may be unequal in strength or intellect, they all become equal by convention and by right. (SC, §1.9)

Up to this point, we have seen that convention binds individuals from within — by virtue of its self-evidence. (Although we have not yet examined Rousseau’s use of the term in detail, the reader will soon see that it closely resembles Hume’s conception.)

On the next page, we will examine Hume’s and Rousseau’s respective uses of convention, in order to explore the notoriously elusive concept of the general will.

*1) “Freedom of men under government is, to have a standing rule to live by, common to every one of that society, and made by the legislative power erected in it; ... and not to be subject to the inconstant, uncertain, unknown, arbitrary will of another man.” (John Locke, Second Treatise of Government, §22)

*2) Here, the term “rule” may be understood as equivalent to “convention” in the present context: “When I follow a rule, I do not choose. I follow the rule blindly.” [Wenn ich der Regel folge, wähle ich nicht. Ich folge der Regel blind.] (Wittgenstein, Philosophical Investigations, §219)

*3) The natural state referred to here denotes the condition of primitive humans prior to the formation of social groups. Such a state likely never existed in any literal sense; rather, it is a hypothetical construct used for explanatory purposes. In this natural state, humans act individually and in isolation, and thus have no concepts of property or justice — only a crude notion of “whoever takes it, owns it.”
However, once humans begin to form groups and enter the social state, the process described in the main text gives rise to concepts of property and justice as human conventions, which then become psychologically binding. Hume and Rousseau both criticize Hobbes for introducing notions such as property and justice — which, by their nature, presuppose social interaction — into the natural state in his construction of Leviathan.

*4) A bear, having no concept of property, feels no pangs of conscience when it steals food from a refrigerator. Likewise, Gian in the natural state — though he possesses human logic (i.e., the brain’s structure and latent capacity) — has not yet internalized any human conventions such as property rights (see *1). For this reason, like the bear, he feels no guilt when taking things from Nobita and does so without hesitation. This is what Rousseau calls liberté naturelle — the kind of freedom that exists in the state of nature — and it is an inherently dangerous condition. It is a world in which force makes right.

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(Japanese ver. @2021.10.3)