## 1. Origins



Public justification arose to resolve problems for social contract
theory.



Classical social contract theorists grounded political legitimacy on
consent. The chief social contract theorists were Thomas Hobbes, John
Locke, Jean-Jacques Rousseau, and Immanuel Kant. They had different
standards of consent; the first three oscillated between an empirical
and a normative standard. The empirical standard draws on actual
mental states: consent justifies political power because it draws on
each party's beliefs and values. The normative standard draws on
somehow rational mental states: we appeal not to what people believe
and value but what they have reason to believe and value. Political
power is justified when grounded in what parties ideally affirm. In
the latter case, we sometimes speak of hypothetical consent as a proxy
for rational justification.



In general, empirical standards gave way to normative standards.
Theorists wanted to legitimize uses of power that contradict what
people actually will. By Kant's time, actual consent views had
disappeared. Hypothetical consent was the state of play. The normative
standard of legitimacy had won out.



All four theorists recognize the diversity of private judgments about
justice. All allowed moral judgments to diverge for any number of
reasons. They all concluded that private judgment could not ground
legitimacy for a diverse public. As Rawls (2005, vii) would put it,
these theorists recognized reasonable pluralism. Citizens who reason
freely will disagree about fundamental values and principles. Contract
theorists concluded that justifications for political power had to
respect diverse judgments. So justification could not rest on one
specific set of beliefs and values. A public justification had to be
impartial, at least among respectable but diverse viewpoints.



The idea of public justification surfaced in Kant's work but
then entered hibernation for a century. Social contract theory gave
way to utilitarianism, Hegelianism, and Marxism. These three schools
of thought rejected the idea of a social contract, though they have
distinct reasons for doing so. The social contract tradition revived
only after World War II, first in the United States.



One of the first new forms of social contract theory was
contractarianism, which justifies coercive institutions through
instrumental rationality: justified political arrangements are
rational bargains among parties for dividing social resources. The
first contemporary contract theorists were economists like John
Harsanyi and James Buchanan. But neo-Hobbesian philosophers pursued a
similar project, especially David Gauthier, Jean Hampton, and Gregory
Kavka.



But the dominant strand of the new contract tradition was Kantian.
Here John Rawls leads the pack in *A Theory of Justice* and
later in *Political Liberalism*. *Political Liberalism*
features public justification as this entry understands the concept.
Rawls first understood public justification as a hypothetical
contract: idealized members of the public choose principles of
justice. Only *Political Liberalism* articulates the challenge
that reasonable pluralism poses for political legitimacy. For Rawls,
the public must adopt principles justified for them despite their
differences. Political power is legitimate only when exercised in
accord with publicly justified norms. (Some theorists use
"justified" and "publicly justified" as
synonyms. See 2.3 below.)



The modern idea of public justification thus only comes into full view
in the early 1990s. Works on public reason and justification published
in rapid succession. They produced a new tradition of political
thought that flourishes today; indeed, public justification is now a
core concept in political philosophy. Yet the idea admits significant
variation, so we now examine those differences.


## 2. The Public Justification Principle



Public justification theories vary. But we can categorize them
according to the *Public Justification Principle* (PJP). Define
the PJP as follows:



> 
> 
> *The Public Justification Principle (PJP)*: A coercive law
> \(L\) is justified in a public \(P\) if and only if each member \(i\)
> of \(P\) has sufficient reason(s) \(R\_i\) to endorse \(L\).
> 
> 
> 



The principle permits individuals 1 and 2 to have different reasons to
endorse \(L\). Public justifications can consist of reasons some in
\(P\) reject. But in this case, \(L\) is still justified for the
public as a whole. The justification encompasses the public but as
distinct individuals. The justification also need not be public as
common knowledge; an individual's reason \(R\_i\) need not be
common knowledge in \(P\).



One can analyze the PJP through answers to the following seven
questions:


1. What makes a reason "sufficient"?
2. How fine-grained is the specification by \(L\) of the conduct
which is permitted or prohibited for members of the public?
3. What types of justificatory reasons \(R\) do we recognize?
4. How are the parties to public justificatory arguments
idealized?
5. What is the scope of the public?
6. What are the modalities of public justification? Or: by which
process is public justification achieved?
7. Must we publicly justify anything other than coercion?



Again, public justification does not require the *presentation*
of reasons. A declaration may produce or uncover a public
justification, but societies may generate public justifications in
other ways (see 2.7). Thus, John can have a justifying reason even if
no one presents it to him through explicit reasoning. We must
nonetheless explain the ideas of a reason and of a sufficient reason
to endorse some law \(L\).


### 2.1 "Sufficient" Reasons



The PJP requires that members of a public \(P\) have reason to endorse
a principle \(L\). One must then explain what it means to "have
a reason to endorse" \(L\).



A common approach to reasons in normative ethics is to take the idea
of a reason as primitive. A reason to \(\Phi\) is a consideration that
counts in favor of \(\Phi\)-ing (Scanlon 1998, 17). But the idea of a
reason in public justification theory is more specific. We do not need
an ontology of reasons, but we must explain when a reason
*justifies* a proposal. Gaus defends a conception of reasons on
epistemic grounds in *Justificatory Liberalism*. One has a
justificatory reason when *openly* justified. A reason is
openly justified when it is "stable in the face of acute and
sustained criticism by others and of new information" (Gaus
1996, 31).



A reason is sufficient when it has some positive epistemic grounds.
Some considerations favor it, and none defeat it. Critically, a reason
can be sufficient for one member of the public but not others. So, a
justifying reason may not justify coercion for all members of the
public. A coercive law is only justified when each person has
sufficient reason to endorse \(L\). Laws gain public justification by
resting on the sufficient reasons of each member.



Public justification theorists assume that our personal reasons for
action and belief can differ, and in some cases, substantially. The
reasons one may offer in public justification may be narrower than
one's personal reasons, but even consensus theorists think that
justifying reasons must, in some sense, adhere to an agent's
beliefs and values. Public justification theorists need not adopt
Gaus's epistemology of justificatory reasons, but the correct
account cannot be too far off.



Public justification theorists thus acknowledge that citizens can
rationally affirm reasons that others reject. And so, different
individuals may have epistemic justification to endorse quite
different reasons. While members of the public themselves need not
recognize these (admittedly) abstruse principles, *theorists*
must accept that two individuals can have reasonable grounds for
affirming diverse and incompatible reasons.



Public justification theory rejects actual endorsement standards,
opting for idealization (as we will see in 2.4). Today theorists
either appeal to counterfactual endorsement or rationally required
endorsement. In the former case, an agent would accept the law through
a deliberate act of will. In the latter case, an agent endorses a law
when rationally committed to affirming it; that is, rationality
requires that she approve it through a deliberate act of will.


### 2.2 Granularity



What is the object of public justification? What is the thing that we
publicly justify? Answers differ, and we can classify them by their
"granularity." Some exercises of political power and state
coercion are small, like legal regulations, while others are broader,
like constitutions. If we take laws as our object of justification, we
take a fine-grained approach. But if constitutions are our object, we
take a coarse-grained approach.



Rawls (2005, 140) adopts a coarse-grained approach, applying public
justification to "constitutional essentials" and
"basic questions of justice." Jonathan Quong (2004,
233-259) adopts a fine-grained approach. He applies public
justification first to laws. Gaus (2011, 495) focuses on laws that
lack "strong interactive effects" with other laws. For
instance, a smoking ban lacks strong interactive effects with a corn
subsidy, and so they should be justified separately.



Gaus's case for fine-grained "individuation" of
proposals involves two arguments. We must justify at a level narrow
enough to identify which forms of behavior are permitted or not. But
we must justify at a level wide enough to see rules as governing
classes of behavior (Gaus 2011, 122-125). This entry's
formulation of the PJP focuses on law \(L\) for brevity, and it
acknowledges that public justification theorists work with other
objects of justification.


### 2.3 Types of Justificatory Reason



A chief disagreement among public justification theorists concerns the
nature of justificatory reasons. Variable \(R\_i\) in the PJP
represents the contrast. The mainstream view within public reason
circles is that justificatory reasons are shared. More accurately,
members of the public can share all justificatory reasons. The reasons
are shareable. (Or, at least, be "accessible" in a sense
outlined below (see 2.3.2)). On these "consensus" views,
\(R\_i\) is the same for each individual \(i\).
"Convergence" views allow \(R\_i\) to differ between
members of the public. John may have his reason \(R\_1\), whereas Reba
may have her \(R\_2\). Citizens can see the reasons as justified
according to reasonable evaluative standards. But they need not adopt
those standards themselves. So, on a convergence view, a private
religious reason can be justificatory. One person's reasons can
differ from another. Each has reasons, but these reasons aren't
the same in the two cases. (See D'Agostino 1996, 30) Again,
religious reasons may form some of those reasons.



The idea of people having different reasons may seem odd to some. But
we recognize convergence reasoning in various contexts. One concerns
market transactions. Suppose \(A\) has apples and \(B\) has bananas.
\(A\) wants some bananas, and \(B\) wants some apples. After a trade,
both have a mixture and regard themselves as better off. Here \(A\)
and \(B\) exchanged for different reasons. And so, the arrangement has
a convergence justification. Each has a reason of their own to prefer
it. And note that the point stands even if \(A\) and \(B\) find one
another's reasons quite alien. Indeed, they might not even know
one another's reasons. But the arrangement still has a kind of
public justification.



So convergence only requires that individuals have their reasons
\(R\_i\), which creates set \(\{R\_1, R\_2 , \ldots ,R\_n\}\) to support
\(L\). Consensus requires, in the limit, that all members of the
public share a (set of) reason(s) \(R\) to endorse \(L\).



But even convergence limits the range of justificatory reasons:
\(A\)'s reasons for endorsing \(L\) might be repugnant, perhaps
enough to undermine \(L\)'s public justification. For this
reason, convergence theorists appeal to idealization (see 2.4
below).



Again, the consensus approach remains dominant. Convergence is in the
minority, both in earlier and contemporary works. (Gaus 1990, 256;
Stout 2004; Klosko 1993 vs Gaus 2011; Vallier 2014; Vallier 2019, Gaus
2021).



But the public reason tradition provides grounds for both approaches.
Rawls seems to have combined the two approaches. Rawls looks like a
consensus theorist in the "freestanding" stage of
political justification. He (2005, 12) says that citizens should use
shared reasons to converge on a political conception of justice. But
in the "overlapping consensus" stage, Rawls leaves
justification "to each person." Each person must sync the
political conception of justice with their comprehensive doctrine, and
the public adopts no single comprehensive doctrine. Rawls included
both accounts of justificatory reasons in his view, yet while the
combined view is attractive, many writers feel compelled to reject
it.



Habermas (1995) provides the most well-known illustration of the
tension in Rawls. Gaus (2011) opts for overlapping
consensus/convergence justifications. Quong (2011) opts for
free-standing/consensus justifications. Vallier and Muldoon (2021)
argue that these answers generate two public reason projects. Gaus
founded a "diversity project" focused on how diverse
reasoning resolves social conflicts. Quong founded a "coherence
project" focused on rendering key political concepts
coherent.



As noted, even convergence theorists adopt restrictions on the set of
justificatory reasons. Some discipline is implicit in the concept of
"a reason." A factual claim does not justify a principle
if evidence falsifies the claim, and a normative claim is not a reason
to endorse \(L\) if it lacks real normative force. So, we need to
articulate some tests that count reasons as justificatory. The entry
organizes them by increasing stringency: intelligibility,
accessibility, and shareability.


#### 2.3.1 Intelligibility



Define intelligibility and the intelligibility requirement as
follows:



> 
> 
> *Intelligibility*: \(A\)'s reason \(R\_A\) is intelligible
> to members of the public if and only if members of the public regard
> \(R\_A\) as justified for \(A\) according to \(A\)'s evaluative
> standards.
> 
> 
> 
> *Intelligibility Requirement*: \(A\)'s reason \(R\_A\) can
> figure in a justification for (or rejection of) a coercive law \(L\)
> only if it is intelligible to all members of the public.
> 
> 
> 



\(A\)'s intelligible reasons are those members can see as
reasons for \(A\), who advances them. And members see \(A\)'s
reasons as reasons for \(A\) based on \(A\)'s own evaluative
standards. Contrast these reasons with mere utterances, expressions of
emotions, or irrational demands: intelligible reasons have rational
grounds.



Intelligibility theorists (Vallier 2016b) argue that reasonable
pluralism applies to evaluative standards as it applies to reasons
(Vallier 2011). Reasonable people can dispute standards of inference
and epistemic justification. For instance, John may regard theological
reasoning as intelligible. To illustrate, he points to the rational
structure of religious exegetical disputes. We may reject
another's sacred texts but think they furnish reasonable
evaluative standards. Others may disagree: sacred texts are too
indeterminate for adequate interpretation. Members may disagree about
what counts as a good cognitive process.



The intelligibility requirement recognizes these differences in
evaluative standards. But it still places pressure on a purely
empirical approach. An empirical approach would count reasons as
justificatory simply because people affirm them. But intelligibility
demands that our reasons for endorsing a principle meet rational
standards. Others must see the reason as one for the person who offers
it, at least according to that person's standard.



Not all intelligible reasons can figure into a justification for some
\(L\). Some intelligible reasons are irrelevant; others only pertain
to the benefits for oneself; still others may not be sufficient to
justify a law, as specified in 2.1. Intelligibility is a requirement
beyond logical sufficiency to give reasons some epistemic credentials.
\(A\)'s intelligible reasons must be available to others to
consider at least as reasons for \(A\).


#### 2.3.2 Accessibility



The accessibility requirement is more stringent than intelligibility.
It does not mandate that a reason for \(A\) to accept \(L\) be
justified according to \(A\)'s reasonable standards. (Even if
others do not share these reasons). Instead, accessibility requires
that reasons be justified according to shared evaluative standards.
(Members believe that \(R\_A\) justifies \(L\) for \(A\) under common
evaluative standards, and \(A\) accepts that \(R\_A\) justifies \(L\).)
Accessibility permits reasons to differ. \((A\) might endorse \(R\_A\)
and \(B\) might not). But it requires that they be evaluated as
reasons according to shared evaluative standards. Thus, accessibility
lies between intelligibility and shareability. (Which we consider
next, in section 2.4.3.) Intelligibility permits differing reasons and
evaluative standards, whereas shareability permits neither.
Accessibility is the most common standard, with at least eight
available interpretations. (Eberle 2002, 252-286; for a recent
defense, see Boettcher 2015). Define accessibility and the
accessibility requirement as follows:



> 
> 
> *Accessibility*: \(A\)'s reason \(R\_A\) is accessible to
> the public if and only if all members of the public regard \(R\_A\) as
> justified for \(A\) according to common evaluative standards
> 
> 
> 
> *Accessibility Requirement*: \(A\)'s reason \(R\_A\) can
> figure in a justification for (or rejection of) a coercive law only if
> \(R\_A\) is accessible to all members of the public.
> 
> 
> 


#### 2.3.3 Shareability



Shareability is the strongest of the three requirements. It combines
shared evaluative standards with the shared reasons requirement
(Bowman and Richardson 2009; Hartley and Watson 2009; Watson and
Hartley 2018). Public reason liberals often argue that justifying
reasons are necessarily shared. But they say little about what it
means to share reasons. Public reason liberals presumably hold that
reasons must be share*able*, in that citizens have the reasons
at the right level of idealization.



Like intelligibility and accessibility, the shareability requirement
has two components: a requirement on the appropriate evaluative
standards and a requirement on the range of permitted reasons. Define
shareability and the shareability requirement as follows:



> 
> 
> *Shareability*: \(A\)'s reason \(R\_A\) is shareable with
> the public if and only if members of the public regard \(R\_A\) as
> justified for each member of the public, including A, according to
> common standards.
> 
> 
> 
> *Shareability Requirement*: \(A\)'s reason \(R\_A\) can
> figure in a justification for (or rejection of) coercion only if
> \(R\_A\) is shared with all (suitably idealized) members of the
> public.
> 
> 
> 



Shareability rules out convergence approaches to public justification,
and citizens may only use shareable reasons in their public uses of
reason. (One could argue that members of the public share any good
reason at high levels of idealization, and here people may even share
their comprehensive doctrines. This point bleeds into the matter of
idealization, addressed below).


#### 2.3.4 A Diagram



Intelligibility, Accessibility, and Shareability are the three core
standards of justificatory reasons in the public justification
literature. They can be grouped together in a diagram:




|  | *Unshared Standards* | *Shared Standards* |
| *Unshared Reasons* | Intelligibility | Accessibility |
| *Shared Reasons* | X | Shareability |



The bottom left quadrant is open--public reason liberals never
advocate shared reasons and unshared evaluative standards. There are
two reasons for this. First, sharing evaluative standards is more
common than sharing reasons. So if reasons are shared, evaluative
standards should be too. Second, evaluative standards help to
individuate and distinguish between reasons. So it's not clear
we could determine which reasons are shared if evaluative standards
are not shared.


### 2.4 Idealization



Once the outer bounds of the public are set (see
 Section 2.5
 below), and we know which individuals have to have reason(s) for some
arrangement to legitimize that arrangement, public reason liberals
must explain how to ascribe reasons to the members of this group.
Specifically, public reason liberals, unless they are empirical
consent theorists, engage in idealization to show how citizens'
beliefs, desires, and values enter into the process of public
justification. Idealization is the practice of considering
citizens' beliefs, desires, and values as if they possessed good
information and good reasoning. It is typically employed because an
individual's morally significant reasons may not be the same as
the reasons she affirms. Her affirmed reasons might rest on poor
information, poor reasoning, or incoherent beliefs and desires.
*Justificatory populism* determines citizens' reasons by
their actual commitments (Eberle 2002, 200).



Rawls's primary model of idealization (1971, 118) is the veil of
ignorance. It models parties as reasonable by withholding information
that would undermine the impartiality of their deliberations. (The
veil device models reasonableness and the parties' veiled
reasoning models rationality.) Jurgen Habermas (1999, 198)
prefers deliberative conditions without abstract idealization. He
constrains the form of discourse to actual individuals. David Gauthier
(1986, 245) prefers a bargaining scenario. Individuals know the
characteristics of persons, but they do not know which person they
are.



Idealization alters citizens' belief-value sets. A
citizen's belief-value set is the set of all her beliefs,
desires, goals, and plans, i.e., everything she thinks and wants.
(This idea derives from Bernard Williams's (1981, 102)
conception of a subjective motivational set.) A citizen is idealized
when we consider her belief-value set as it might be. Theorists change
one or more of her beliefs, desires, and goals according to some
criteria. They may imagine her having more or different information or
values. Or they must insist on modeling her as fully rational. Both
models alter her belief-value set. And the appropriate level of
idealization might vary with context. Perhaps it depends on the
epistemic quality of reasoning demanded by the situation. (Some
reasoning aims to design institutions, whereas one might use other
reasoning to plan a family vacation).



To motivate idealization, consider how public justification fares
without it. Populist views "take citizens as they are: the
default populist position is that a rationale \(R\) counts as a public
justification only if the members of the public find \(R\) acceptable
in light of their existing [subjective motivational sets],
irrespective of their epistemic pockmarks and doxastic defects"
(Eberle 2002, 200). Populist conceptions of idealization have severe
problems. People can "withhold their assent because of
obstinacy, selfishness, laziness, perversity, or confusion"
(Gaus 1996, 121). Populism also problematically requires asking
everyone about their reasons before deciding whether a coercive law is
justified.


#### 2.4.1 Radical Idealization



Public justification theorists typically prefer radical idealization.
They do this to fix the weaknesses of justificatory populism and alter
belief-value sets to rid them of inconsistencies and ignorance.
Radical idealization thus has two dimensions--rationality and
information--pushed to their upper bound.


##### 2.4.1.1 Rationality



The distinction between full rationality and less-than-full
rationality is central to idealization. Though, as we will see, full
rationality is elusive. To attribute reasons to citizens based on poor
reasoning corrupts public justification. A theory of full rationality
idealizes agents by giving parties flawless cognitive powers. (See
Rawls (1971, 12) and Gauthier (1986, 234) for explicit attributions of
full rationality to their agents.)



The assumption of full rationality initially seems irresistible. If we
can discern the reasons citizens would affirm if perfectly rational,
surely these reasons would be morally relevant. The public reason
liberal tries to justify demands and coercion to members of her
society. How could she do better than full rationality? Another
motivation for embracing full rationality is to generate agreement.
Many assume that suitably idealized individuals will agree on matters
they otherwise would not. Rawls ascribes full rationality to parties
to the original position to induce agreement. Were they less than
fully rational, the parties might reach different conclusions.



But problems with full rationality abound. First, the notion of full
rationality may be incoherent when applied to finite and fallible
beings (see Cherniak 1986). It requires adjusting a dense web of
beliefs and values. And these beliefs and values are not computable in
real-time given limited resources. Second, full rationality will
produce justifications that individuals cannot reflectively endorse.
Individuals' actual beliefs and values differ significantly from
those which justify the arrangements. (This is one way in which the
problem of stability might arise. See below 5.2.)


##### 2.4.1.2 Information



Again, public reason liberals add information to the belief-value set
of ordinary citizens. (And, indeed, remove misinformation.) They
thereby avoid holding public justification captive to ignorance.
Rawls, Gauthier, and Habermas all pursue this strategy. Their models
assume that idealized agents have all (and only) the facts that
determine what reasons they have. Public reason liberals remove
beliefs and desires that stop individuals from adopting an impartial
perspective. They add such general and specific information necessary
for the agent to reason well about the issues before her. Public
reason liberals disagree about what sets of information interfere with
impartiality. But all theorists subtract misinformation and biasing
information.



Informational idealization ranges between complete information and
adequate or relevant information. The motivations for embracing and
rejecting full information resemble those for full rationality. A full
information account is attractive because it attributes reasons to
citizens based on many true propositions and no false ones. Further,
complete information might guarantee determinate recommendations, and
if agents share relevant information, they will tend to converge on
similar conclusions. Yet, complete information may model citizens in
an implausibly abstract fashion, and it gives them powers that no
finite and fallible being has.


#### 2.4.2 Moderate Idealization



Public reason liberals take criticisms of radical idealization
increasingly seriously. (See Gaus 2011, 232-260 and Vallier
2014, 145-180.) If these criticisms are successful, one might
reconsider returning to justificatory populism. However, there may be
a third option: moderate idealization. Moderate idealization assigns
reasons based on some standard of adequate information and reasoning.
Yet it falls short of full information and perfect reasoning. The
moderate idealization theorist argues that we can go too far in
separating idealized belief-value sets from citizens' dingy,
real-world belief-value sets. We will eventually sever the tie between
them. And, as Wolterstorff insists (2007, 153), the idealized person
may have no reason to care about his counterpart's
recommendations. (Also see Enoch 2013, 164-170; for a reply, see
Gaus 2015). The pull toward radical idealization must balance
respecting citizens as they are. (This latter element will be crucial
for maintaining stability; see 5.2.) Radical idealization may test the
"strains of commitment" (Rawls 1971, 155-9) in
demanding that citizens cognitively struggle to see what reasons they
have. But moderate idealization may prove acceptable to most ordinary
citizens. Moderate idealization is an appropriate acknowledgment of
the demands of the impartial perspective.


#### 2.4.3 Reasonableness



Idealization limits the set of reasons that figure into public
justification. "Normative" idealizations that represent
the public as reasonable do likewise. In one way, reasonableness may
seem to be a redundant category. Rawls, Gauthier, and Habermas
represent citizens as reasonable by depriving them of partializing
information. But reasonableness is not redundant. It attributes
cognitive dispositions to agents uncaptured by idealizing beliefs,
desires, and values.



Rawls's conception of the reasonable plays two roles in his
theory of justice. First, the veil of ignorance models reasonableness.
But a citizen of the well-ordered society is also reasonable because
she possesses the following four dispositions (Rawls 2005,
49-52, 53-58, 60, 76, 119, 162-3, 229). (1) A
disposition to engage in public justification or to offer
justifications for her own preferred principles and abide by the
justified principles proposed by others. (2) A disposition to
recognize the "burdens of judgment" implies reasonable
pluralism. (3) A disposition to reject the repression of other
reasonable points of view. (4) A disposition to rely on methods of
reasoning that others can share or access.



Public reason liberals share something like the standard conception of
reasonableness. But idealizing members of the public as reasonable
runs into two problems. First, such idealization risks ruling too many
citizens out of the justificatory public. Second, representing the
public as reasonable might forestall justifying coercive social
arrangements in a way that helps them to approximate a voluntary
agreement (Nagel 1987).


### 2.5 Scope of the Public



The scope of the public determines who to idealize. Public
justification theorists typically identify the public with members of
a traditional nation-state. Theorists do this to simplify, but also
due to an implicit nationalism. Rawls confined his theory of justice
to members of a nation, though he later developed an account of public
justification for global matters (2002). This matter is left to
debates about nationalism and cosmopolitanism (see the entries on
 nationalism
 and
 cosmopolitanism).



Public reason liberals tend to leave future generations out of the
public (though see the entry on
 intergenerational justice).
 Some theorists, like Gauthier, confine public justification to
persons capable of cooperation. But most theorists apply public
justification to all citizens.


### 2.6 Modalities of Public Justification



The PJP can also specify which social processes establish public
justification. We can sort social processes into four types:
discursive, universalizing, bargaining, and evolutionary. Discursive
views identify public justification with an agreement reached between
public discussants. Universalizing approaches identify public
justification with fair and reciprocal principles. Bargaining
approaches identify publicly justified principles as those that
maximally advance individual interests. Evolutionary approaches are
the most distinctive. They distinguish sharply between public reason
and public justification. In their view, a coercive principle \(L\) is
publicly justified when it is a stable, evolved public equilibrium. No
process of public reasoning needs to take place. These four theories
each have a prominent representative. In order they are Jurgen
Habermas, John Rawls, David Gauthier and Gerald Gaus.


#### 2.6.1 Discursive



Discursive theories understand public justification as generating
agreement among disputants through a process of real discourse under
just and fair social institutions. Such views divide into Habermasian
and pragmatist theories (Talisse 2005; Misak 2000). We can outline the
discursive view by reviewing Habermas's account (see the entry
on
 Jurgen Habermas).



Habermas holds (1999, 68) that "the justification of norms and
commands requires that a real discourse be carried out." The
only way to achieve public justification is through free
argumentation. Such argumentation convinces citizens to recognize the
claims others make on them. For \(A\) to make a legitimate claim on
\(B\), \(A\) must submit his claim to \(B\)'s critique. The
discursive process forms each individual's conception of her
interests and commitments. Habermas calls this process "will
formation." Personal opinions can change and then produce a
rational consensus. Habermas idealizes in this way to define a
conception of the reasonable. Citizens take a discursive, moral point
of view. Their goal is to reach a rational consensus about the
interests of the public. (For details about how idealized discourse
proceeds, see Habermas 1999, 65-6.)


#### 2.6.2 Universalizing



Universalizing views try to identify a regime that fairly advances
everyone's interests in accord with how individuals understand
those interests. Rawls exemplifies this view: a theory of justice
justifies claims that citizens make on one another's conduct
from our perspectives. Given how much people disagree, Rawls knows
that gaining traction on justification is complex, and he responds by
converting it into a problem of social choice. Rawls: "the
question of justification [can be] settled by working out a problem of
deliberation" (Rawls 1971, 16). Principles of justice are
publicly justified when parties to a proper choice situation select
them.


#### 2.6.3 Bargaining



Bargaining views call a regime legitimate for an individual when it
maximally advances her interests. Bargaining suggests a negotiation
that yields a stable equilibrium of opposing forces: each person
achieves as much as she can, consistent with the needs of others. The
most prominent example of a bargaining theory is David
Gauthier's contractarianism. Gauthier argues that citizens need
a social morality to secure social cooperation. We identify moral and
political norms as justified when it is instrumentally rational for
each agent to accept them.



Individuals "faced with the costs of natural or market
interaction in the face of externalities agree to a different,
cooperative mode of interaction." Rational individuals do so to
"maximize their own utility" (Gauthier 1986, 145-6).
The goal is to show why anyone should accept moral restraints on their
behavior. Gauthier proposes that even instrumental rationality can
justify ethical constraints to all. A citizen can be subject to state
coercion in certain respects because it is in his interests. Gauthier
does not base public justification on the total utility it produces.
Parties strike bargains where each person provides the minimum
relative concession of rents. Publicly justified rules maximize each
person's share, but joint maximization constrains each
person's claim. Each side seeks the best bargain they can
get.



In recent years, both Michael Moehler (2018) and Peter Vanderschraaf
(2018) have revived bargaining approaches to public justification.
Moehler develops a "two level" theory of practical
rationality for social contract theory. Bargaining reasoning is the
fallback position when more moralized contracting fails.
Vanderschraaf's book, *Strategic Justice*, takes the
bargaining approach to its highest level of sophistication.


#### 2.6.4 Evolutionary



Evolutionary views are, again, the newest approach. The approach
arguably originates in Bryan Skyrms (1996). But Gerald Gaus (2011) is
today the most well-known proponent of such a view. Evolutionary views
are new because they react to perceived failures of other approaches.
Gaus, for instance, rejects bargaining views, claiming that parties to
public justification must be intrinsic rule-followers. We can follow
rules that frustrate our goals. Gaus argues that agents who follow
moral rules for instrumental reasons cannot sustain cooperation
because its members still have reason to defect when others cooperate.
Moral agency, he concludes, must allow us to decline to maximize the
satisfaction of our goals.



For Gaus, then, parties will not accept every instrumentally rational
bargain. They also know that public discourse will not resolve their
disagreements. And a universalizing approach will yield multiple
eligible social arrangements; universalizing strategies are
indeterminate. Gaus appeals to social evolution to produce convergence
on an eligible understanding, which would otherwise be indeterminate.
When society reaches an undefeated agreement, it achieves public
justification. Each party sees no other way to secure social
cooperation. Public reason combines with a sociological thesis:
spontaneous order processes can converge on norms. No one foresees or
constructs the justified principle or rule. But all have reason to
accept the outcome of such a process.



Evolutionary views draw on "adaptive" rationality,
contrasted with "calculated" rationality (March 1978). An
agent is rational when she adapts effectively to her environment, so
her rationality does not depend on how she adapts, only that she
adapts well. Calculated rationality occurs when one adapts through
deliberative decision-making. Many theorists assume the PJP is a
principle of calculative reason. But evolutionary theorists reject
this claim. \(L\) is publicly justified for \(P\) if each member has
sufficient reason to endorse \(L\). Full stop. Public justification
obtains even if justificatory reasons differ. It even obtains when
these reasons are the consequence of an equilibrium process. The
reasons need not derive from explicit deliberation.



Gaus continued the evolutionary project up to *The Open Society and
Its Complexities* (Gaus 2021). The book draws complexity economics
and agent-based modeling to determine when and in what circumstances a
diverse population will converge on common rules. Here Gaus draws on
Ryan Muldoon (2019), who introduced agent-based modeling into social
contract theory. Muldoon uses his theory to challenge consensus views
of public reason.


### 2.7 Coercion Alone?



Typically public justification addresses the permissibility of
political coercion. Coercion might apply to constitutional essentials
and basic justice (Rawls 2005). Or it applies to coercive law as well
(Quong 2011). Yet some theorists extend public justification beyond
coercion. Gaus (2011) and Chad Van Schoelandt (2015) argue that public
justification evaluates relations of moral authority. We publicly
justify our practice of making moral demands of others, even if the
rules we demand others follow are not coercive. Colin Bird (2014)
grounds public justification in the standing of democratic citizens as
co-authors of legislation. In Bird's view, we must justify
non-coercive legislation that affects the status of citizens. An
example might be communicative legislation that defines an optionally
sworn national pledge of allegiance. Some public reason theorists
broaden the idea of coercion to cover structural coercion (Boettcher
2016, Wong 2020).


## 3. The Liberty Principle



The PJP only explains how to justify coercion (or some related form of
demand). It includes no other moral principle that describes why
coercion is problematic. Nor does it explain how to handle unjustified
coercion. So, one might combine the PJP with a consequentialist norm.
Unjustified coercion, on this view, merits minimization. Or we could
adopt a deontological side constraint on using unjustified coercion.
Again, on this matter, the PJP is silent.



And yet, many public justification theorists, with other liberals,
adopt such a principle. Some theorists call it the Liberty Principle.
It takes the form of a presumption in favor of liberty or against
coercion. Stanley Benn (1988, 87) defends such a presumption. Benn:
"the burden of justification falls on the interferer, not on the
person interfered with."



Joel Feinberg (1987, 9) also defends a "presumption in favor of
liberty." Defined: "liberty should be the norm, coercion
always needs some special justification." While Benn worries
about interference, and Feinberg about coercion, their presumptions
are similar. Rawls (2001, 44) endorses a presumption against legal
coercion, which also appears in his liberal principle of legitimacy.
Rawls: "Our exercise of political power is proper only when we
sincerely believe that the reasons we offer for our political action
may reasonably be accepted by other citizens as a justification of
those actions" (Rawls 2005, xlvi). Rawls does not speak of
coercion in this formulation. Yet he elsewhere claims that
"political power is always coercive power" (68). Further,
public justification should explain when citizens may coerce another
(217). We can naturally read Rawls, then, as endorsing the Liberty
Principle. Gaus (2011) probably provides the most extensive defense of
the liberty principle to date (though see Vallier 2019).



We can conjoin the PJP with the Liberty Principle. Together, they
explain how to use the PJP to evaluate laws. When satisfied, the PJP
legitimizes coercion, overcoming the presumption in favor of
liberty.


## 4. Foundations of the Public Justification Principle



Now we inquire into the foundations of the PJP. Why should anyone
accept it? The set of proposed normative foundations has increased
with time. Classically, public justification rests on respect for
persons as free and equal. (See Larmore 2008; for criticism, see
Eberle 2002, Gaus 2011 and Van Schoelandt 2015). Others ground the PJP
in an analysis of the nature of rationality and morality (Habermas
1996). One dominant view bases the PJP on requirements of justice
(Rawls 2005: Quong 2013). Some draw on the value of civic friendship.
(See Lister 2013, Ebels-Duggan 2010, Leland and van Wietmarschen 2017,
van Wietmarschen 2021, Neufeld 2022. For criticism, see Billingham
2016.) Gaus adopts a PJP because he argues that publicly justified
rules avoid authoritarianism and fit with the reactive attitudes (for
criticism, see Tahzib 2019, Taylor 2018). At a deeper moral level,
these rules preserve moral relations between persons. (Gaus 2011,
Vallier 2022. For criticism, see Enoch 2013 and Enoch 2015.)



Watson and Hartley (2018) rest public justification on respect for
persons and reciprocity. Vallier (2019, 2020) grounds a PJP in the
value of social trust or trust between members of society (though see
Tahzib 2021). Neo-Hobbesian views have seen a revival in the work of
Moehler (2018) and Vanderschraaf (2018); they have much more developed
theories of instrumental rationality as a basis for public
justification.



For space purposes, I omit a discussion of these foundations, as it
would only recapitulate the argument found in the entry on
 public reason.



A related foundational question asks who merits a public justification
in the first place (this question relates to the question of the scope
of public justification, but is logically prior to it). Quong (2011,
137-160) applies public justification to an idealized
constituency of reasonable people. Gaus (2011, 232-268) directs
public justification to actual persons; their justifying reasons are
those that survive moderate idealization. Quong calls his view the
"internal conception" of political liberalism. He
contrasts it with the "external conception." The external
conception directs public justification to natural persons as they
are. But few public reason liberals adopt the external view. The
Gausian model appeals to a limited idealization, not none. The
internal conception has been subject to several criticisms. (Gaus
2012, Billingham 2017a, Vallier 2017). But theorists also criticize
the Gausian approach (Enoch 2013, Quong 2014).



Deciding who merits a public justification requires explaining its
point. For Quong and others, public justification renders consistent
our fundamental political ideals. Examples include the idea of society
as a system of cooperation and persons as free and equal. For Gaus,
public justification establishes moral relations between natural
persons (Gaus 2011). These relations are ones of equal respect. But
they also lay the foundation for closer ties of trust, love, and
friendship.



The internal/external conception contrast no longer serves to classify
public reason liberals. Vallier and Muldoon (2021) have argued that
public reason has split into two projects. The first project, which
they call the *coherence project*, characterizes the internal
conception; it involves rendering our political ideals consistent. The
project contrasts with the *diversity project*; diversity
theorists use diverse reasoning to achieve real-world public
justification. Vallier and Muldoon (2021) set the external conception
aside.



The *original project*, advanced by Rawls and traditional
Rawlsians, continues (Weithman 2011). But the coherence and diversity
projects arose from a shared worry about it. Rawls uses both consensus
and convergence reasoning in legitimizing state coercion. We first
justify a conception of justice based on shared values, and we then
see if it can become the object of an overlapping consensus. Coherence
theorists say the first stage is critical, while the second stage is
confusing. But diversity theorists say the second stage is necessary
as a heuristic for finding points of convergence. Original project
theorists refuse to choose between these two justificatory stages.



For the most recent work in the coherence project, see Neufeld 2022.
For the most recent work in the diversity project, see Gaus 2021.
Gaus's work has pushed public reason so far in a diversity
direction that in some ways it is no longer a form of social contract
theory (Gaus 2018). Gaus now models the choice of principles as a
socially interdependent choice process, and not a single agreement.
Gaus even began developing a research program based on these insights
called the New Diversity Theory (Gaus 2018b).


## 5. Sister Concepts



The PJP ties itself to two essential concepts: publicity and
stability. A law that achieves stability and publicity may thereby
count as publicly justified. In other cases, theorists see reaching
publicity and stability as theoretical merits--considerations
that favor their approach to public justification over others. If a
version of the PJP conflicts with publicity, that could refute the
specification. Other factors can count against this specification of
the PJP. But publicity and stability are central to public
justification, so we explore connections.


### 5.1 Publicity



For Rawls, "public justification" occurs when a
well-ordered society achieves "full publicity." Full
publicity contains three levels (see the entry on
 publicity).
 The first level occurs when public principles of justice effectively
regulate society. Rawls (2005, 66): "citizens accept and know
that others likewise accept those principles, and this in turn is
publicly recognized." Each person sees society's basic
structure as justified by shared reasoning.



The second level requires that citizens of a well-ordered society have
shared beliefs. In particular, they believe that all can accept the
first principles of justice. Their evaluations draw on "general
beliefs about human nature" and how institutions work (67).



Level three establishes "the full justification of the public
conception of justice as it would be presented in its own
terms." It must include all considerations relevant to
generating a conception of justice. Then the full justification
becomes "publicly known" or at least "publicly
available."



Full publicity arises when all three levels of publicity occur. When a
society reaches full publicity, its conception of justice becomes
publicly justified. Yet this is so only given two conditions. The
conception of justice must become a political conception. It must
derive from shared and public political values. Second, it must reach
an overlapping consensus. Full publicity comprises "public
justification," Rawls's third stage of justifying a
political conception. It occurs when each person knows that the
political conception is fully justified. (Rawls 2005, 386-7).
For Rawls, "public justification happens when all the reasonable
members of political society carry out a justification of the shared
political conception by embedding it in their several reasonable
comprehensive views." Thus, public justification obtains via
publicity.



Charles Larmore (2008, 203-7) traces Rawls's idea of
public reason to concerns about publicity. Paul Weithman (2011, 242)
stresses the centrality of publicity in Rawls. Publicity helps educate
society about the basis of its political views. And it is crucial for
maintaining a community as stable for the right reasons.



Rawls's notion of publicity is the most common in the
literature, but Gaus (2011, 296-7) offers a less demanding
"weak" publicity standard. Notice, then, that
Rawls's conception of publicity is quite demanding. The PJP does
not insist that public justifications achieve full publicity, and most
theorists say that people should be able to tell when laws or rules
are publicly justified. Publicity is a "sister concept" to
public justification when it helps to establish public
justification.



Some theorists define publicity as the publicity of shared reasons.
(See Rawls 2002, 173.) They adopt a consensus approach to aid public
recognition that public justification occurs. (See Hadfield and Macedo
2012; Watson and Hartley 2018.) And yet, consensus and convergence
views appeal to publicity. Both approaches want citizens to know when
laws or policies are justified for all. Convergence theorists may not
define the PJP as including shared values, but they still find
publicity attractive. This difference draws on the contrast between
intelligibility and accessibility discussed above.



Publicity remains a central topic in this literature, but has gone
without major treatments until Kogelmann 2022.


### 5.2 Stability



Stability is the other sister concept to public justification. Many
public reason liberals think publicly justified principles must be
somehow morally stable. Rawls (2005, 140-3) advances this line:
public justification helps political conceptions become "stable
for the right reasons."



Weithman (2011) argues that Rawls's changing ideal of stability
drove revisions to his theory. Rawls wanted his political principles
to reach stability in a diverse society despite reasonable pluralism.
In some ways, concerns about stability are a reason to care about
public justification. A community may only reach moral stability, that
is, stability for the right reasons if each person has moral reason to
endorse society's coercive power. Otherwise, stability rests on
a balance of power alone--a *modus vivendi* regime.



Some theorists draw a looser connection between stability and public
justification. Whether a principle can stabilize is a reason to prefer
it over less stable principles. (Rawls sometimes talks this way in
*Theory*.) Stability may also help vindicate a conception of
public justification over others. So, suppose that a convergence view
helps justify laws in ways that promote stability. If so, we may have
reason to adopt a convergence over a consensus view.



Rawls's focus on stability raises another complex issue. The
present entry addressed idealizing persons as reasonable or not
(2.4.3). Some idealizations attribute reasons to citizens based on
what they would reasonably endorse. Stability is also sometimes
moralized. It is valuable only when based on "the right
reasons." Rawls resists merely prescriptive stability, however.
He does not want to stabilize a society based only on what ought to
make it stable. Instead, stability has content apart from its basis in
moral reasons. A community can be unstable even if its institutions
rest on reasonable grounds. Stability has an ethical ideal and a
descriptive ideal of real stability. Public justification then can
have both moral and descriptive parts. Publicly justified rules are
both real and justified. Gaus has criticized Rawls (1996, 130-6)
for his populist conception of stability. He has developed an
alternative (2011, 389-408). So, many public justification
theorists feel the pull of descriptive and moral stability. But some,
like Quong (2011), adopt a purely normative notion.



Following Weithman (2011), philosophers now explore stabilization
mechanisms. Weithman argues that public reasons create stability for
the right reasons and that this was Rawls's view.



Vallier and John Thrasher (2015) think public reasons are poor
assurance signals. They raise problems associated with cheap talk and
misinformation. These factors may be present even in well-ordered
societies. Kogelmann and Steven H. W. Stich (2016) embrace convergence
discourse for stability. Convergence allows people to use diverse
reasons as costly signals of cooperative inclinations. It takes a
great deal of effort to speak the political languages of various
groups. The use of diverse discourse can thus create stability. This
literature continues to bear fruit.


## 6. Objections



This entry as a whole explains the ideal of public justification, so
it does not explore objections to public justification in detail.
Instead, it offers a comprehensive list of criticisms. Some items in
the list draw on a shorter list constructed by Jonathan Quong (2011,
259-60). In general, the objections aim at particular
conceptions of public justification, but unless specified, assume that
critics direct their complaints against all versions of public
justification discussed.


### 6.1 The Incompleteness Objection



Many critics of public justification claim it cannot address critical
political issues. This problem arises from restrictions on permissible
reasoning in public life. (De Marneffe 1994, Reidy 2000; Schwartzman
2004). Critics here object to consensus views, which restrict the set
of justifying reasons. Citizens may not have shared reasons and
instead appeal to personal considerations, so the convergence view
makes this objection less pressing.


### 6.2 The Indeterminacy Objection



Critics have argued that public reason liberals embrace excessively
indeterminate conceptions of justice. The ideal of public
justification cannot make determinate recommendations. Gaus (2011)
presses this objection against Rawlsian conceptions of public
justification, resolving indeterminacy by appealing to actual
evolutionary mechanisms (see 2.7.4). This "normalization"
objection rejects attempts to avoid indeterminacy by adopting
homogenizing assumptions. (D'Agostino 2003)


### 6.3 The Antidemocratic Objection



Deliberative democrats have complained that Rawls identifies justice
apart from real deliberation. Habermas famously (1995, 127-8)
lodged this criticism against Rawls. This objection targets Rawlsian
universalizing public justification.


### 6.4 The Integrity Objection



Some say public justification imposes excessive burdens on people of
faith. By barring unshared reasons, it excludes religious reasons from
public discourse. Critics say people of faith have no reason to accept
those constraints. (Eberle 2002, Wolterstorff 1997, Vallier 2014). The
constraints, if followed, would divide the identity of religious
people, and the person of faith's identity may disintegrate.



The integrity objection relates to a fairness objection. This
objection claims that public justification prioritizes secular over
religious reasons, arbitrarily preferring secular citizens. (Perry
1993, Wolterstorff 1997). Note that convergence undermines these
objections as it allows appeals to religious reasons. (Eberle 2012).
The integrity objection also relates to the Denial of Truth objection
(Neal 2009). Neal thinks citizens who abide by public justification
cannot appeal to the truth as they see it. Andrew March (2013)
provides a taxonomy of religion-based criticisms of public reason. He
argues that some restrictions can burden us too much. But other
conditions are justified.


#### 6.4.1 The Antidiscourse Objection



Public justification might also support unrealistic views of
democratic politics because real politics uses personal reasons to
build coalitions and forge compromises (Shapiro 1999). This objection
focuses on the burdensomeness of public reason, but it also concerns
whether public reason is realistic. Note that the antidiscourse
objection threatens discursive views of public justification.


#### 6.4.2 The Marginalization Objection



Some critics argue that public justification privileges logical, calm,
dispassionate forms of discourse. There may be minority groups that do
not find such speech rules satisfactory. (It is a matter of
controversy who these minority groups are.) The objection mirrors the
integrity objection, but they apply to different social groups.
(Sanders 1997, Young 2000). These critics oppose Rawlsian
interpretations of the PJP.


### 6.5 The Unreasonableness Objection



Public reason liberals often say many citizens are unreasonable, but
this claim meets powerful resistance due to its ambiguity. Others
object because uses of the reasonable privilege some over others, so
the standard is inegalitarian. (Bohman 2003, Friedman 2000). This
objection focuses on Rawlsian interpretations of PJP.


### 6.6 The Asymmetry Objection



Public reason liberals argue that reasonable people will disagree
about the human good. But they also claim that reasonable people will
agree on conceptions of justice. Some critics say these claims are
problematic because they are asymmetric. The same factors that drive
reasonable pluralism about the good apply to justice, hence the
asymmetry. (For discussion and rebuttal, see Quong 2011,
192-220.) This objection applies to a wide range of
interpretations of the PJP. But convergence theorists often accept
justice pluralism. (Gaus 2011, 276-9; Gaus and Van Schoelandt
2017, Vallier 2019, Gjesdal 2022).


### 6.7 The Self-Refutation Objection



The PJP holds that all coercive actions or laws require justification
for each member of the public. But critics ask whether this treatment
applies to the PJP itself. If so, then given that reasonable people
disagree about the PJP, the PJP is self-refuting. But suppose the PJP
needs no public justification; if so, its defenders make an arbitrary
exception for their moral principle. (Wall 2002; Christiano 2010,
206-213; Estlund 2008; Wall 2013; Enoch 2013,
170-173).



Some respond by arguing that their version of the PJP can satisfy
itself (Estlund 2008). Other public reason liberals exclude the PJP
from public justification, but they then argue that the exclusion is
not arbitrary. (Gaus 2011; Vallier 2016a; Bajaj 2017. This objection
applies to any interpretation of the PJP. For a more recent
discussion, see Billingham 2017b.)


### 6.8 The Perfectionism Objection



Liberal perfectionists claim that the state should promote the
authentic human good. They reject public justification for preventing
governments from promoting that good. And they reject the ideas of
"neutrality" and "restraint" that justify the
PJP. (Wall 1998, Chan 2000.) For some prominent replies, see Quong
2011. Perfectionists reject the PJP itself, not merely some
interpretations of it.


### 6.9 The Empty Set Objection



The most powerful objection to the PJP is that it allows too many
reasons to defeat proposed laws. The objection applies to various
interpretations of the PJP. But critics direct it most often at the
convergence views. (Eberle 2012; Enoch 2015, though see Schultz-Bergin
2021) By allowing diverse defeaters into public justification, few
proposals reach public justification. Few states can engage in their
most basic functions. Some public reason liberals admit that public
justification is often beyond us. (Rawls 2005, D'Agostino 2006).
We may need some degree of social development to establish a publicly
justified polity. (Rawls 2005).



Gaus offers the most prominent response. The benefits of shared norms
can populate an otherwise empty set of proposals. The idea here is
that we all rank some rules ahead of no rule governing some issue.
While we regard some rules as sub-optimal, they improve our relations
with others. This reply is a sociological response: people prefer
sub-optimal ethical rules to no rules because empty sets are
debilitating. Both Rawls and Gaus provide such arguments. (Rawls 2002,
124-128, Gaus 2011, 303-333, 389-408,
424-447).



In short, each person may have a defeater for another's
preferred moral rule. But most members of the public prefer some
ethical governance to none, and in that case, they may deem some moral
rules acceptable but not optimal.


### 6.10 The Insincerity Objection



This objection threatens convergence views. Quong thinks permitting
personal reasons allows citizens to be insincere with one another.
Convergence citizens can offer others reasons they do not believe are
good reasons. (Quong 2011). This objection does not address the
distinction between shared reasons and standards. We are not insincere
if we offer others reasons that follow our modes of inquiry but end up
in a different place. If we share a scientific method, yet end up with
different theories, we may have varied reasons. But sharing diverse
reasons is not insincere when our shared background is common
knowledge.



Quong's consensus constraints also appear to bar reasoning by
conjecture. (Rawls 2002, Schwartzman 2012). Conjectural reasoning
allows persons to appeal to the reasons of other comprehensive
doctrines. But both parties are aware of the nature of such appeals.
That said, sincerity requirements may still have an essential role in
public reason. (Schwartzman 2011)


### 6.11 Theoretical Indeterminacy



Fred D'Agostino (1996) argues that the PJP admits many variants.
(We characterize the variants through values in the PJP.) We have
reasons to favor a range of interpretations of the PJP. For example,
public justification appeals to idealization. But we have grounds to
idealize radically, moderately, or not at all. (Macedo 1990 makes
these points.) Unfortunately, the case for idealizing, but not
idealizing too much, is complicated and involves conflicting
desiderata. True, conflicting desiderata are common in any theoretical
domain. Still, D'Agostino worries that conceptions of public
justification arise from incompatible motivations, and theorists lack
conceptual resources to weigh these considerations against one
another. In his final book, Gaus (2021) argues that even his earlier
evolutionary model of public reason (Gaus 2011) would not lead to
convergence on rules in many cases; but with diverse agents in a free
and interactive model of rule choice can converge on rules more
often.


### 6.12 Concerns about Idealization



Public reason liberals, again, feel intense pressure to idealize. But
some critics think idealization is always arbitrary.



Eberle (2002) claims idealizations reflect the biases and values of
theorists, which is why largely secular public reason liberals
suppress religious reasons. So, any version of the PJP that appeals to
idealization is subject to this objection.



David Enoch (2013) rejects Gaus's moderate idealization. Contra
Gaus, such idealization does not show that social-moral rules reduce
authoritarianism. Nicholas Wolterstorff (2007) argues that coercing
someone based on an idealization is patronizing. Even disrespectful.
For recent papers on idealization, see Besch 2019, Donahue 2021,
Vallier 2020b.



In light of these objections, Fabian Wendt (2019) has tried to
separate public justification from public reason liberals. He hopes to
capture what is attractive about public justification while separating
it from problems with public reason in liberal political thought.


### 6.13 New Objections to Convergence



In recent years, consensus theorists have pushed back against
convergence views in detail. While these arguments are all unique,
they are worth noting as a general phenomenon. See Badano and Bonotti
2020, Boettcher 2020, Tahzib 2021, Neufeld 2022. But the debate rages
on from convergence theorists; see Motchoulski 2020.


## 7. Applied Issues



Theorists often use public justification to address important applied
questions. Applied questions concern religion in liberal democracies,
religious exemptions, feminism, marriage policy, environmental issues,
healthy eating policies, and even public reason and Confucianism.
Applied issues are the order of the day in much of the literature.



On the religion in politics literature, see the entry on
 religion and political theory.
 Also, see literature reviews in March 2013, Vallier 2014, and Bailey
and Gentile 2014. While many public reason liberals have moved away
from a restraint-based approach to religion in public life (Gaus and
Vallier 2009, Laborde 2017, newer work defends such principles (Watson
and Hartley 2018). Some even focus public reason on discourse, setting
public justification aside (Leland 2019). Still other theorists have
focused on developing principles of restraint appropriate for managing
partisanship and the conduct of political parties (Bonotti 2017).



We have seen the rapid expansion of the literature on public reason
and religious exemptions, brought into clear focus in Cecile
Laborde's (2017) work. (Also see Bespalov 2019.) Some of the
exemption literature extends into medical exemptions. See McConnell
and Card 2019.



Public reason and feminism discussions are now voluminous. (Okin 1994,
Rawls 2002, Nussbaum 2003, Baehr 2008, Hartley and Watson 2009,
Hartley and Watson 2010, Neufeld and Van Schoelandt 2014, and Watson
and Hartley 2018).



To explore public justification and marriage policy, see Brake 2010,
Macedo 2015, Chambers 2017, and Toop 2019.



Public reason methods have also been applied to environmental issues
(Shahar forthcoming; Nielsen and Hauge-Helgestad 2021), as well as
healthy eating policy (Bonotti and Barnhill 2019).



We are also seeing the beginnings of a discussion about the
intersection of public reason and the Confucian religion (Kim 2019;
D'Ambrosio 2019).



We have also seen the introduction of new formal methods into public
reason, such as social choice theory (Kogelmann 2017, 2019; Chung
2020), agent-based modeling (Muldoon 2019, Gaus 2021), and fixed-point
theorems (Schaefer 2022).