Does Interpersonal Justifiability Ground Normativity?

Exploration v0.2 · 2026-09-08

1. Separate contractarianism from contractualism

This page distinguishes Hobbesian contractarianism from Rawlsian, Scanlonian, Habermasian, and public-reason forms of contractualism. The former tries to derive cooperative constraints from interests, preferences, and strategic rationality. The latter begins with thicker normative inputs such as free and equal persons, reasons, reasonable rejectability, or public justifiability.

Contractarianism: preferences/interests + strategic rationality → mutually advantageous constraints
Contractualism: persons/reasons/standing + interpersonal justifiability → normative principles ?

The central question is therefore not whether agreement exists, but why justifiability to others should possess genuine normative authority.

2. Contractualism as a family of justificatory devices

Rawls's original position, Scanlon's reasonable rejection test, Habermas's ideal discourse, and Gausian public justification are not equivalent. Their common structure is the attempt to connect normative validity with what can be justified among multiple persons.

agreement ≠ non-rejectability ≠ discourse acceptability ≠ public justification.

It is useful to treat contractualism as a design space defined by who counts as a subject, what inputs count as reasons, how agents are idealized, which operator selects principles, and how the output is interpreted.

3. Rawls I — what does the original position do?

The original position is not a historical contract but a device of representation. It models free and equal citizens choosing principles for the basic structure under a veil that excludes knowledge of class, wealth, talents, religion, and particular life plans.

free and equal persons + veil of ignorance + rational choice → principles of justice

Its major strength is that it refuses to convert real bargaining power directly into justice. Being richer, healthier, more talented, or part of a majority does not automatically confer greater moral entitlement.

4. Rawls II — is the veil normatively neutral?

Yet the choice of what to hide is not neutral. Social position and natural talents are excluded because their influence is treated as morally arbitrary for purposes of selecting principles of justice.

normative judgment → design of veil → output principles

The veil is therefore not mere information reduction. It is a normatively designed information filter. In a Hobbesian world, power differentials are strategically relevant facts; Rawls removes them from the justificatory input.

Equality → fair contract is not the same as fair contract → Equality. If free and equal personhood must already be supplied, the procedure has not generated equality from nothing.

5. Harsanyi — the veil does not uniquely imply Rawls

In Harsanyi-style impartial-observer arguments, uncertainty about which person one will be can be represented as a risk over social positions and evaluated using expected utility. In a simplified form:

P(i)=1/N,   EU=(1/N)ΣU_i

This can support an average-utilitarian result. Hence:

Veil of Ignorance ⇏ Rawlsian justice.

Different assumptions about utility, interpersonal comparison, risk, and decision rules yield different outputs. More generally:

Procedure output = f(inputs, idealization, decision rule).

6. Sandel — are contractual subjects pre-social?

The useful part of Sandel's criticism here is not that communities are normatively authoritative, but that contractual subjects themselves may be socially constituted. A Rawlsian representation can make the self look prior to its particular ends and capable of choosing or revising them.

Yet:

Community + History + Relations + Institutions → Self → Ends

may be closer to the actual causal structure. Family, language, religion, class, and institutions shape not merely what agents value, but what they are able to recognize as a reason.

Still, social constitution ⇏ communal authority. A community's causal role in producing a subject does not make its values correct.

7. Subjects, preferences, and reason-judgments are endogenous

Contractual procedures often take subjects and their preferences or reasons as inputs. But institutions themselves help produce the next generation of subjects, preferences, and reason-judgments.

Institutions + Culture + Power + Education → Subjects / Preferences / Reason-judgments

Institution_t → P_t/R_t → Justification_t → Institution_t+1

A stable justificatory equilibrium may therefore be either evidence-sensitive or simply institutionally reproduced. Those possibilities need to be distinguished.

7.1 Cordasco — an internal correction to fixed-preference contractarianism

Carlo Ludovico Cordasco's 2026 paper “Abstraction as Flexibility: The Veil of Evaluative Uncertainty” is better read as a modification of Buchanan/Gauthier-style contractarian bargaining through evaluative uncertainty than as Scanlonian contractualism. It does not hold actual present preferences fixed: the present agent has prudential reason to account for the possibility that its future evaluative outlook will change.

Instead of merely P_t + bargaining → I, the structure becomes approximately P_t + uncertainty about P_{t+1} + endogenous option menu → flexibility-driven institutional agreement. Because the menu itself is institutionally generated, agents can bargain over option-generating and option-filtering meta-rules rather than only over currently available options. In this respect Cordasco supplies a significant internal response to the criticism that contractarian models treat preferences as fixed exogenous inputs.

Endogeneity nevertheless reappears one level higher. The current higher-order values that screen which futures count as recognizable members of the flexible set can themselves be products of culture, education, institutions, and history. Thus a loop such as institutions/history → higher-order values_t → recognizable futures → flexible set → future institutions remains possible. Endogenizing the menu does not by itself make the meta-values used to evaluate that menu independently normative.

It would therefore be inaccurate to criticize Cordasco as though he claimed that agreement creates objective normativity. His central argument is prudential and instrumental; it does not purport to derive strong fairness or objective moral truth from contract. The distinction Policy convergence ≠ Value / Metaethical convergence functions here as a boundary on scope rather than a refutation: a successful flexibility-driven agreement can preserve useful institutional openness without thereby discovering normative truth.

For the relation between this argument, Cordasco's later missing-menu work, and the project's broader value inquiry, see From Value Uncertainty to Normative Discovery.

8. Scanlon I — reasonable rejection, not actual agreement

Scanlonian contractualism does not ground wrongness in actual consent or bargaining advantage. An act is wrong when it is disallowed by principles no one could reasonably reject.

Wrong(a) ⇔ a is disallowed by principles no one could reasonably reject.

Actual rejection ≠ reasonable rejection. A slaveholder's objection to losing status or property does not automatically count against abolition. Contractualism thereby separates bargaining power from normative standing.

9. Scanlon II — what makes a rejection reasonable?

But this exposes the foundational question. If a slaveholder's status loss and an enslaved person's freedom and domination claims are compared, what makes the latter the stronger reason?

R_n,A, R_n,B, ... → reasonable rejection → wrongness

If this is the structure, contractualism may not generate R_n at all. It may instead be an operator for organizing already-existing reasons person by person.

This connects directly to the Reasons First exploration. If reasonable rejection depends on robust normative reasons, the ultimate burden returns to why those reasons are genuine.

10. Complaints and aggregation

A major Scanlonian attraction is resistance to simple summation. A large number of trivial benefits need not automatically outweigh a severe burden imposed on one person.

1000 × small complaint   vs   1 × serious complaint

But this creates its own aggregation questions. When do numbers matter? Which complaints are comparable? How are severity and multiplicity combined? The aggregation operator itself requires justification.

11. Who counts as a rejecter? The standing problem

Contractualism can detach standing from bargaining power, but then must explain who has standing in the first place.

ability to bargain ≠ ability to reject ≠ normative standing.

Infants, severely disabled persons, animals, future persons, digital minds, copies, and branching or merging agents cannot be handled simply by actual participation. Proxy representation also reintroduces normative assumptions about what counts as their interests or reasons.

12. Future persons and subject-set endogeneity

For future generations, policy can determine who exists. If policy X creates person A while policy Y creates person B, there is no fixed participant set N in advance.

Policy → Subject set

The nonidentity problem is therefore also a structural problem for contractual procedures: the set of subjects to whom justification is owed can itself depend on the output of the procedure.

13. Habermas — ideal discourse rather than actual consensus

Habermasian discourse ethics does not identify actual agreement with validity. It asks what all affected could accept under discourse conditions corrected for coercion, asymmetries of information, domination, and strategic manipulation.

Norm valid ⇔ all affected could accept it under rational discourse.

This is stronger than actual consent, but it moves the problem upward: why are ideal discourse conditions themselves normatively authoritative? Conditions such as freedom from coercion, reciprocity, publicity, and adequate information are already normatively structured.

14. Is idealization error-correction or normative input?

Rawls, Scanlon, and Habermas all idealize actual agents in some way.

P_i → P_i^*,   R_i → R_i^*

Removing misinformation, impulsiveness, or prejudice may seem straightforward, but the treatment of family attachment, self-preservation, nationalism, envy, fear, or anthropocentrism is much less so.

normative idealization criterion → idealized subject → consensus

If so, consensus does not independently create normativity.

15. Gaus — public justification without deep convergence

A central attraction of Gausian public justification is that deep agreement on values need not be achieved.

R_A ≠ R_B ≠ R_C

while:

R_A → X,   R_B → X,   R_C → X

can still support X as a publicly justified rule. The goal is less metaethical convergence than a mutually acceptable order under persistent pluralism.

16. Separate policy convergence from truth convergence

Agreement on institutions does not imply agreement on reasons, values, or metaethics.

Policy convergence ≠ Reason convergence ≠ Value convergence ≠ Metaethical convergence.

A religious believer, utilitarian, liberal, and egoist can endorse the same policy for different reasons. Public justification may therefore succeed precisely by avoiding deep convergence, rather than by discovering 𝒱*.

17. The Hobbesian null model — how much emerges without contractualism?

The Hobbesian contractarian exploration supplies a useful null model. Even with no robust normative reasons, repeated interaction, reputation, commitment, deterrence, and avoidance of manipulation races may generate contracts, reciprocity, publicity, non-aggression, and some fairness-like rules.

R_n=∅ + preferences + strategic interaction → morality-like cooperation

Hence the existence of moral-looking cooperation is not enough to establish contractualist normativity.

The crucial question becomes: What does contractualism add beyond the Hobbesian null model? Equal standing, reasonableness, non-strategic claims, and justification to each person are plausible answers—but those are exactly the inputs whose normative authority requires explanation.

18. Preference intervention and the genealogy of reason-formation

Manipulated consent is easy to model:

A → P′_B → B accepts X

so Consent ⇏ Justification. Contractualism is more robust than simple contractarianism because it does not rely on actual consent.

Yet if agents can shape others' reason-judgments themselves:

A → R′_B → B reasonably accepts X ?

then reasonable acceptance also needs a genealogy. Education, institutions, discourse, power, and cognitive environments can shape what agents recognize as reasons. Rationalized acceptance is not automatically independent truth-tracking.

19. Connection to reflective equilibrium

Rawls relies not only on the original position but also on reflective equilibrium among considered judgments, principles, and background theories. The two methods have different roles.

Contract / construction: models candidate principles and conditions of justification.
Reflective equilibrium: revises judgments, principles, and background theories against one another.

But both face the same higher-order problem of normative authority in input / filter / operator. Contractualism idealizes agents; reflective equilibrium filters for considered judgments. Neither filter is automatically neutral.

20. Does procedure generate normativity?

Contractualist procedures can be represented schematically as:

Input + Filter + Idealization + Operator → Output

Rawls: free/equal persons + veil + choice rule → justice.
Scanlon: reasons + reasonable filter + rejection operator → wrongness.
Habermas: participants + ideal discourse + acceptability → validity.
Gaus: diverse justificatory reasons + public justification → eligible social rules.

The key point is that a normative output does not show that the procedure created normativity from nothing. Normativity may already reside in the input, filter, idealization, operator, or interpretation of the output.

21. Complete-error-world stress test

As an extreme test case, suppose robust normative reasons do not exist at all:

R_n=∅

Agreement, discussion, consensus, reciprocity, policy convergence, and stable equilibrium can still exist. Shared psychology, common interests, coordination gains, power, education, and persuasion may generate even widespread convergence.

Agreement / Convergence ⇏ Normative truth.

If convergence is used as evidence for normative reality, one must compare not only P(Convergence | 𝒱*) but also P(Convergence | Error World).

22. Three levels of contractualist success

Weak success: multiple agents → mutually acceptable rules. This is success as social coordination.

Moderate success: public justification → stable, reciprocal, non-dominating institutions. This can be a powerful political theory of legitimacy.

Strong success: interpersonal justifiability → R_n / normative validity. This is the genuinely metaethical step and needs separate grounding.

23. Provisional judgment — strongest as interpersonal organization of reasons

Contractualism became a major tradition because it can address coercion, equality, pluralism, publicity, and legitimacy without requiring a single comprehensive conception of the good. That is a real strength.

But the strongest parts of Rawls, Scanlon, Habermas, and Gaus may lie less in creating normativity from nothing than in organizing already-given standing, reasons, equality, and justificatory constraints among multiple persons.

Contractualism may be strongest as a theory of interpersonal organization of reasons, without thereby being a theory of where reasons ultimately come from.

On a Scanlonian reading, the structure may be Reasons → Contractualist operator → Wrongness, not Contractualist operator → Reasons. On a Rawlsian reading, it may be Normative conception of persons → Fair procedure → Justice, not Neutral procedure → Normativity.

Sources / notes

Primary references include John Rawls, A Theory of Justice and Political Liberalism; John Harsanyi's impartial-observer and expected-utility arguments; Michael Sandel, Liberalism and the Limits of Justice; T. M. Scanlon, What We Owe to Each Other and Being Realistic about Reasons; Jürgen Habermas on discourse ethics; and Gerald Gaus, especially The Order of Public Reason. For an evaluative-uncertainty correction to fixed-preference contractarianism, see Carlo Ludovico Cordasco, “Abstraction as Flexibility: The Veil of Evaluative Uncertainty” (2026). Useful overviews include the Stanford Encyclopedia of Philosophy entries on “Contractualism,” “Original Position,” “Public Reason,” and “Habermas.” The aim here is not a complete history of interpretation but a comparative test of whether interpersonal justifiability is foundational normativity or an operator over prior normative inputs.