## 1. What is Structural Rationality?


### 1.1 The Emergence of the Concept of Structural Rationality



The term 'structural (ir)rationality' is relatively
recent; to the best of our knowledge, its first use with its current
meaning is in Scanlon
 (2007).[2]
 However, philosophers have been theorizing about the underlying
concept, using different terminology, for significantly longer.
Interesting questions can be asked about whether historical figures
such as Hume and Kant had theories of structural rationality. However,
the contemporary debate about structural rationality can be more
directly traced to a number of important articles and books from the
1970s and 80s (Hill 1973; Greenspan 1975; Dancy 1977; Darwall 1983),
which largely focus on practical rationality.



Darwall's 1983 book *Impartial Reason* is particularly
instructive to focus on. The first half of the book is devoted to
arguing against what Darwall calls the "DBR thesis", on
which an agent's normative reasons are all dependent on her
desires or ends - a thesis that was highly popular at the time.
One line of support for the DBR thesis to which Darwall responds can
be reconstructed roughly as follows:


1. It's irrational not to intend to take the believed means to
one's ends.
2. Therefore, not intending to take the believed means to one's
ends involves a failure to respond to one's reasons.
3. Therefore, one's reasons are strongly dependent on
one's ends.



This line of argument, if successful, generates strongly subjectivist
(and anti-moralist) results about reasons. For example, to adapt
Darwall's memorable example, suppose Jo intends to kill Jay in
the most violent way possible, and believes that the most violent way
to kill Jay is with a cleaver. But suppose Jo does not intend to kill
Jay with a cleaver. Jo is, then, practically irrational. According to
the line of thought above, the way to explain this is by holding that
Jo's intention to kill Jay in the most violent way possible
- perhaps together with her belief that the most violent way to
kill Jay is with a cleaver - gives her a strong *reason*
to (intend to) kill Jay with a cleaver. Generalizing, the result is
that Jo can give herself strong reasons to perform highly immoral (or,
indeed, imprudent) acts merely by adopting ends to which those acts
are (believed) necessary means.



Not so fast, says Darwall, however. He focuses on critiquing the
transition from (a) to (b) - though one could certainly also
question the transition from (b) to (c). According to Darwall, the
irrationality of failing to (intend to) take the (believed) means to
one's ends need not equate to a failure to respond to
one's *reasons*. Rather, it can be understood as a
failure to conform to a *sui generis* rational requirement of
coherence, which itself has no consequences for claims about reasons.
Darwall calls such requirements principles of "relative
rationality"; this notion is roughly equivalent to the more
contemporary notion of structural rationality. As well as treating the
requirement of instrumental rationality this way, Darwall makes a
similar move regarding decision-theoretic principles that require us
to do what maximizes subjective utility given our credences and
preferences.



The basic maneuver here recurs in the works of a number of other
philosophers (McDowell 1995; Scanlon 1998, 2004; Broome 1999, 2001a,
2004; Dancy 2000). In each case, the aim is to avoid highly
subjectivist or anti-moralist results about reasons, or instances of
what is often called "bootstrapping" (Bratman 1987; Broome
2001a), whereby merely having an attitude that is itself immoral or
unreasonable can give one reasons to adopt further immoral or
unreasonable attitudes. And in each case, these results are avoided by
treating the requirements of structural rationality as autonomous and
distinct from requirements that concern responding to reasons. By
making space for a distinctively structural or coherence-based notion
of rationality, the thought goes, we can accommodate intuitions about
the irrationality of incoherence without committing ourselves to
potentially problematic subjectivist assumptions about normative
reasons.



Analogous points can be made in doxastic cases. To adapt an example
from Fogal (2020), suppose that Ali believes that he is Superman, and
believes that Superman can fly. If we now add that Ali believes that
he cannot fly, Ali seems to be subject to a (further) charge of
irrationality that he was not otherwise subject to. Should we conclude
from this that, merely by believing that he is Superman and that
Superman can fly, Ali gives himself a strong *reason* to
believe that he can fly - one that he flouts by believing,
instead, that he cannot fly? Many epistemologists would deny this: on
most views, you can't make an evidentially unsupported belief
reasonable just by adopting other, equally unsupported, beliefs that
entail it. Indeed, as Broome (1999) points out, if this were so, then
any belief could make itself reasonable, since all propositions entail
themselves. Rather, the thought goes, we can account for Ali's
irrationality by saying that he violates a requirement of structural
rationality forbidding inconsistent beliefs (or, perhaps, particular
kinds of inconsistent beliefs).



Once reasons and requirements of structural rationality are
distinguished in this way, a number of important questions arise. One
pressing question is whether there are any reasons to comply with the
requirements of structural rationality. We'll return to this
question in SS3. Before that, there is more to be said about the
notion of structural rationality and requirements thereof.


### 1.2 Key Characteristics of Structural Rationality



As we have already seen, evaluations of structural rationality concern
the coherence of one's mental states. However, we can get a
sharper focus on the notion of structural rationality by identifying
some further often identified features of evaluations of structural
rationality or irrationality, which are supposed to distinguish them
from evaluations of substantive rationality or irrationality.



First, structural rationality typically concerns *combinations*
of attitudes (and absences thereof), rather than *individual*
attitudes (and absences thereof). Consider someone who believes \(p\)
and believes not-\(p\). Either or both beliefs may fail to be
substantively rational if they are ill-supported by the agent's
epistemic reasons. But the structural irrationality lies in the
combination, not in either individual belief. The same is true of, for
example, intending to \(\Phi\), believing that in order to \(\Phi\)
one must \(\Psi\), but not intending to \(\Psi\). Again, one or more
of these states may fail to be individually substantively rational,
but the structural irrationality lies in the combination. However, it
is controversial whether structural rationality *always*
concerns combinations of attitudes, rather than individual attitudes.
Broome (2013: 153), for example, suggests that a belief in a
conjunctive proposition of the form \((p\) & not-\(p)\) is, on its
own, structurally irrational. Nor is it *distinctive* of
structural rationality that it concerns combinations of attitudes.
There may be failures of substantive rationality that obtain
specifically in virtue of a combination of attitudes: for example, it
might not be substantively rational to intend to go to a job interview
tomorrow *and* intend to wear swim shorts tomorrow, even if
either of these intentions is rationally permitted on its own.



Second, and relatedly, evaluations of the structural rationality of
some combination of attitudes can be made independently of judgments
about which (if any) of the individual attitudes within the
combination of attitude is substantively rational, or adequately
supported by reasons. For example, suppose that Ravi believes that all
taxes are illegitimate, while also believing that income taxes are
legitimate. A left-liberal might judge that Ravi has good reasons for
the second belief but not the first, while an anarcho-capitalist might
judge the reverse, and a political agnostic might have no views about
which of Ravi's beliefs, if either, is supported by good
reasons. Yet this should be no barrier to all three agreeing that
Ravi's *combination* of beliefs is structurally
irrational. Similarly, even when we disagree about whether some end is
worth pursuing, we should be able to agree that intending that end
while not intending the believed means to it is structurally
irrational.



Third, evaluations of structural rationality can be made without
knowing anything about the situation of the agent being evaluated, or
about the agent's information about their situation. In this
respect, they again contrast with evaluations of substantive
rationality. Whether it is substantively rational for you to intend to
go to medical school depends on the information available to you about
your likely chances of succeeding in medical school, the costs of
going, whether being a doctor would be a career you'd enjoy, and
so on. We cannot possibly evaluate the substantive rationality of your
intention to go to medical school without knowing what information is
available to you about these matters. But if you simultaneously intend
to go to medical school, believe that to do so you must take the
entrance exam, and yet do not intend to take the entrance exam, then
we can tell that you are structurally irrational, without needing to
know this sort of information.



Finally, evaluations of structural rationality may be called
*formal* in the sense that we can tell whether combinations of
attitudes are structurally irrational even when abstracting at least
somewhat from their content. So, for example, it's always
structurally irrational to believe \(p\) and believe not-\(p\), for
any proposition \(p\), regardless of its content. Similarly, the
means-end requirement says (or entails) that it is irrational to
intend to \(\Phi\), to believe that to \(\Phi\) one must \(\Psi\), and
not intend to \(\Psi\), for any actions \(\Phi\) and \(\Psi\),
regardless of what they are.


### 1.3 The Relationship Between Structural and Substantive Rationality



The distinction between structural and substantive rationality is not
beyond dispute. Some hold that it does not bear scrutiny. Moreover,
those who accept the distinction hold competing views on its
significance as well as on the relation between substantive and
structural rationality.



First, there are those who identify rationality *simpliciter*
with structural rationality (Scanlon 1998; Broome 2013, 2020; Ridge
2014: ch. 8). Such philosophers deny that what others call
'substantive rationality' is genuinely a kind of
rationality at all: they hold that the requirements of structural
rationality exhaust the requirements of rationality
*simpliciter*. It is debatable to what extent this dispute is
merely terminological or substantive. These philosophers don't
deny that there is an important normative notion - viz.
'ought' or 'most reason' - that can be
understood in terms of what one's reasons, on balance, support.
But they want to withhold the label 'rationality' from
it.



One argument for withholding the label 'rationality' from
(what we've called) substantive rationality proceeds from the
purported conceptual constraint that rationality supervenes on the
mind: there can be no change in whether an agent counts as rational
without a change in her mental states (Wedgwood 2002; Broome 2013,
2020). It then holds that reasons do not supervene on the mind:
one's reasons can change without one's mental states
changing. Thus, it is concluded, rationality cannot require us to
correctly respond to our reasons. The argument can be supported by
intuitions about cases. In a famous case (Broome 2007a), Lois has a
piece of fish in front of her, which unbeknownst to her, contains
salmonella. The fact that the fish contains salmonella is a decisive
reason for Lois not to eat it; yet, since Lois is unaware of this
reason, she cannot be irrational for failing to respond to it.
Arguably, it is precisely because rationality supervenes on the mind
that Lois cannot be irrational for failing to respond to a reason that
she is entirely unaware of.



Defenders of the notion of substantive rationality reply that the
notion of 'reasons' at work in the conception of
rationality as reasons-responsiveness is in some important way
constrained by the agent's epistemic position (Kiesewetter 2017;
Lord 2018). Perhaps, for example, substantive rationality requires us
to respond only to the reasons that our evidence makes available to us
- often called "available" or
"possessed" reasons. If this is so, then eating the fish
may well be substantively rational for Lois. Moreover, while
unpossessed reasons do not supervene on the mind, it is less clear
that the same is true for possessed reasons. Thus, the rational
requirement to correctly respond to these reasons may be compatible
with the supervenience of rationality on the mind (Kiesewetter
2020).



It is also worth noting that the proposal that rationality
*simpliciter* is just structural rationality is much less
popular in epistemology than it is in ethics and the practical
rationality literature (Worsnip 2016b). In epistemology, it is
orthodoxy that agents who fail to respond to their evidential reasons
for belief thereby fail to be
 rational,[3]
 and thus that there are rational requirements of
reasons-responsiveness - i.e. requirements of substantive
rationality. By contrast, purely coherentist theories of epistemic
rationality - which effectively identify epistemic rationality
with a kind of structural rationality - are now widely
rejected.



A second view about the relationship between structural and
substantive rationality contends that these two notions of rationality
ultimately come to the same thing (Wedgwood 2017; Smithies,
forthcoming). This position can be motivated in part by taking on
board the aforementioned point that substantive rationality requires
us only to respond to those reasons that our evidence makes available
to us. Putting this together with the claim that our evidence consists
in or at least supervenes on our mental states, it can be argued that
the rational requirement to respond to our evidentially available
reasons is itself a requirement to ensure a kind of coherence between
our mental states, in a broad sense of 'coherence'. Thus,
it is argued, the distinction between substantive rationality (viz.
reasons-responsiveness) and structural rationality (viz. coherence)
breaks down.



Defenders of the structural-substantive distinction respond that the
notion of (in)coherence that we should employ in order to understand
structural rationality is narrower than the one needed to break the
distinction down (Fogal and Worsnip 2021). Consider someone who has a
belief that is insufficiently supported by her (available) evidence:
say, she believes that the Orioles will win today's baseball
game, when her (available) evidence doesn't, in fact, give her
sufficient grounds for thinking this. Suppose, however, that she holds
her belief not in knowing defiance of her evidence, but rather because
she simply mistakenly overestimates the probative strength of her
evidence. In this case, she has a belief that is insufficiently
supported by her (available) evidential reasons, and thus fails to be
substantively rational. Yet it is only in a very broad sense of
'incoherent' that she is incoherent. In a narrower sense
of 'incoherent', she need not be incoherent: as long as
she does not recognize what her (available) reasons support believing,
there seems to be no internal clash between her attitudes here. This
narrow sense of 'incoherent' - it is held - is
the one relevant for structural rationality. This position can be
bolstered by appeal to the central characteristics of structural
rationality identified in SS1.2 above. The judgment that there is
a rational shortcoming involved in believing that the Orioles will win
today depends on substantive judgments about reasons, and the
circumstances and evidence of the agent. Moreover, this rational
shortcoming isn't an instance of a more general pattern of
irrationality that can be identified in abstraction from the content
of the attitude involved. Additionally, the narrower sense of
(in)coherence relevant for structural (ir)rationality is held to
obtain only between what Scanlon (1998, 18ff.) has called
"judgment-sensitive attitudes", such as beliefs and
intentions, and cannot involve other mental states such as
perceptions, which are not responsive to judgment or reasoning. Thus,
to have beliefs that are out of whack with one's perceptual
evidence will not be incoherent in this narrower sense, nor
structurally irrational.



A third set of views holds that, though substantive and structural
rationality can be intelligibly distinguished, one is reducible to the
other. Some hold that structural rationality can be reduced to
substantive rationality (Kiesewetter 2017; Lord 2018; Henning 2018;
Lasonen-Aarnio 2021; see also Singh forthcoming). One way of effecting
this reduction is via the claim that what it is to be structurally
irrational is to have a combination of attitudinal mental states such
that it is *guaranteed* that, whatever one's situation
(and thus, one's reasons) is like, at least one of the mental
states fails to be substantively rational (Kiesewetter 2017:
235-39; see also Kolodny 2007a and 2008 and Lord 2018 for
related ideas). For example, it seems plausible that whatever
one's situation (and thus, one's reasons) is like,
one's evidence can never sufficiently support both believing
\(p\) and believing not-\(p\). If this is so, then to believe \(p\)
and believe not-\(p\) is to have a combination of attitudinal mental
states such that it is guaranteed that, whatever one's situation
is like, at least one of these mental states fails to be substantively
rational. Similarly, it might be thought, one's reasons could
never support intending an end *and* believing that a means is
necessary for that end, while also supporting *not* intending
the means; and this is what makes the combination structurally
irrational. Notice that this view is not one on which structural and
substantive irrationality turn out to be the same property: having
attitudes that guarantee a failure to respond correctly to one's
reasons (structural irrationality) is a stronger property than merely
having failed to respond correctly to one's reasons (a failure
of substantive rationality). It thus accommodates the natural idea
that structural rationality involves a distinct kind of failure.



Critics of this view push back in a number of ways, but perhaps the
most common response is to point to cases where jointly incoherent
attitudes are individually permitted by one's reasons (Broome
2013: 85-6; Way 2013). For example, suppose that your evidence
indicates that to go to the supermarket, you must get on your bike
(thus permitting, or perhaps even requiring, belief in this
proposition). And suppose that your reasons permit, but don't
require, you to go to the supermarket. In that case, it seems like
your reasons permit, but don't require, you to get on your bike.
In that case, neither the intention to go to the supermarket, nor the
belief that to do so you must get on your bike, nor the absence of an
intention to get on your bike, fails to be substantively rational. Yet
it seems that the three are still structurally irrational in
combination. If this is right, then the structural irrationality of
some combination of attitudes is not a guarantee that at least one of
the attitudes fails to be substantively rational. Similarly, perhaps
there are permissive cases with respect to one's doxastic
attitudes (Ballantyne and Coffman 2011; Schoenfield 2014). For
example, perhaps your evidence can permit a credence of 0.6 for \(p\),
but also permit a credence of 0.61 for \(p\). Correspondingly, then,
it permits a credence of either 0.39 or 0.4 for not-\(p\). In that
case, neither a credence of 0.61 for \(p\) nor a credence of 0.4 for
not-\(p\) fails to be substantively rational. Yet the combination of
the two is structurally irrational (Staffel 2020).



Various strategies have been proposed to deal with this challenge.
Kolodny (2011) and Lord (2018: Ch.2) both suggest that the adoption of
an intention can alter one's reasons to take the means,
rendering a means-intention that was merely permitted prior to the
adoption of the end-intention, substantively required (an analogous
story about credences is suggested in Lord 2020). Drawing on work by
Bratman (1987), Kiesewetter (2017: Ch. 10) argues that in cases of
merely permissible ends, means-end incoherent agents will flout
*economical* reasons because maintaining intentions that one
will not carry out makes one susceptible to waste resources. With
respect to doxastic incoherence, it is also an option to reject the
kind of permissivism that is in conflict with explaining structural
irrationality in terms of substantive requirements of rationality
(e.g., White 2005, Schultheis 2018). On one alternative view,
substantive epistemic rationality permits us to have imprecise
credences rather than several precise credences that are
probabilistically incoherent.



Other philosophers can be understood as pursuing a reduction in the
opposite direction: that is, a reduction of substantive rationality to
structural rationality. For example, some hold that what it is to have
a reason to \(\Phi\) is to be such that, *were* one's
mental states to be corrected for structural irrationality, one would
be motivated to \(\Phi\) - or desire to \(\Phi\), or intend to
\(\Phi\), or similar (Smith 1994; Markovits 2014). Such accounts of
reasons are often called "idealized attitudes" accounts.
If reasons can be reduced to facts about structural rationality, this
plausibly provides the materials to reduce substantive rationality
(itself understood in terms of reasons-responsiveness) to facts about
structural rationality too. However, idealized attitudes accounts of
reasons have been subjected to numerous objections (see e.g. Enoch
2005). One important objection in the present context is that it is
quite unclear how to generalize this view to reasons for (and thus,
the substantive irrationality of) belief (Cuneo 2007: ch. 7). Another
is that, since there is typically more than one way to correct for
structural irrationality, such views will leave it radically
indeterminate what our reasons are, or perhaps generate reasons for
almost anything (Sampson 2021).



Fourth, and finally, some philosophers hold that substantive and
structural rationality are both equally genuine kinds of rationality
and that neither is reducible to the other (Worsnip 2021). Such views
owe us an account of how, if at all, these two kinds of rationality
relate to one another: for example, can they come into conflict with
one another? If substantive rationality often recommends one thing and
structural rationality recommends another, this may seem
dissatisfying, especially if there is nothing to be said about which
demand takes rational precedence. Indeed, some may think the prospect
of structural and substantive rationality conflicting shows that they
can't both be bona fide sources of rational requirements.



However, it's worth noting that the extent of any conflicts
between structural and substantive rationality depends on the positive
theory of structural rationality that we adopt. On a
"wide-scope" view about structural rationality (see
SS2.1 below), its requirements are merely negative, prohibiting
incoherent combinations of attitudes, and one can come to satisfy the
relevant requirement by revising *any* of the incoherent
attitudes. If this is so, it reduces the potential for conflicts
between substantive and structural rationality. This is because, on
this view, structural rationality simply tells one that one should
restore coherence in *some* way when one is incoherent, and
this leaves room for substantive rationality to (sometimes) determine,
more specifically, *which* way to do so. For example, consider
again Ali, who believes that he is Superman and that Superman can fly.
If Ali's evidence is normal, substantive rationality prohibits
Ali from believing he can fly. Does structural rationality require him
to believe he can fly? Not obviously: it might permit him instead to
revise one of his original beliefs, requiring only that he
*either* believe he can fly *or* revise one of these
original beliefs. Some have argued, however, that conflicts between
substantive and structural rationality can arise in subtler ways in
special cases (Worsnip 2018a).


### 1.4 Instances of Structural (Ir)rationality: An Inventory



So far, we've focused mostly on inconsistent beliefs and
means-end incoherence as paradigm instances of structural
irrationality. But there are many other putative instances. Any
particular instance will be controversial, since it is always up for
debate whether some combination of mental states really is
structurally irrational. And it is not feasible to be completely
comprehensive in identifying all the candidate instances. But we will
draw attention to some of the (patterns of) combinations of states
that are among the most plausible candidates.



Let's begin with some combinations of doxastic states that are
plausibly structurally irrational. Along with strictly contradictory
beliefs - i.e., a belief in \(p\) and a belief in not-\(p\)
- it is often thought that other logically inconsistent sets of
beliefs are structurally irrational. For example, as mentioned
earlier, it seems structurally irrational for Ali to believe he is
Superman, believe that Superman can fly, and yet believe that he
cannot fly. More strongly, some have thought that it is structurally
irrational to fail to believe the logical entailments of one's
beliefs - so that Ali would be irrational were he to believe
that he is Superman, believe that Superman can fly, and merely
*fail to believe that he himself can fly*. The requirement that
one believes the logical entailments of one's beliefs is often
called 'deductive closure'.



However, there are thorny issues about whether *all* instances
of inconsistency, or of failing to believe the logical entailments of
one's beliefs, involve irrationality. First, it is not clear if
this is so when the relevant inconsistency or entailment is extremely
subtle and would take a complex logical proof to detect (Broome 2013:
154-5). Second, it is not clear that we are irrational for
failing to clutter our minds with the infinite trivial consequences of
our existing beliefs (Harman 1986: 12). In response to the first
problem, some say that structural irrationality obtains only when one
*recognizes* the relevant inconsistency or entailment
(Sainsbury 2002). In response to the second, some say that, where
\(q\) is some consequence of one's existing beliefs, one needs
to care about whether \(q\) (Broome 2013) or attend to \(q\) to be
structurally irrational for failing to believe \(q\). However, these
restrictions do not deal with all purported cases of rational
inconsistency. For example, the preface paradox (Makinson 1965) is a
plausible case of rational but inconsistent beliefs (see esp.
Christensen 2004). In this case, an author writes a book containing a
number of claims, but modestly affirms in the preface that doubtless,
the book contains errors - i.e., that at least one of the claims
in the book is false. This total set of beliefs - the claims in
the book, plus the preface claim - is inconsistent, but
arguably, it is not irrational to hold these beliefs - even if
one recognizes the inconsistency, and attends to and cares about the
relevant beliefs. While some (MacFarlane 2004 - see Other
Internet Resources) hold that this is a case where substantive and
structural rationality conflict, others (Worsnip 2016a) have argued
that the inconsistent beliefs in these cases are not even
*structurally* irrational.



It is also widely held that agents can be structurally irrational in
virtue of the ways that their first-order beliefs combine with their
higher-order beliefs: that is, with beliefs about the normative status
of their first-order beliefs, or about their evidence for them. For
example, it's often thought to be structurally irrational to
believe \(p\) while also believing that one's evidence does not
adequately support \(p\) - or to fail to believe \(p\) while
also believing that one's evidence decisively supports \(p\)
(see, among many others, Kolodny 2005; Feldman 2005; Titelbaum 2015).
Such combinations of states are sometimes described as
"epistemically akratic" (Horowitz 2014; Greco 2014). While
some deny that such states must be irrational on the grounds that they
can be rational in cases of misleading higher-order evidence (Coates
2012; Lasonen-Aarnio 2020), others think that it is at most
*substantively* rational, but not structurally rational, to be
epistemically akratic in such cases (Worsnip 2018a).



Many of the kinds of irrationality pinpointed by formal
epistemologists, which typically pertain to credences rather than to
full belief, can also be plausibly regarded as structural. For
example, (most) failures to conform one's credences to the
axioms of probability - such as the aforementioned case of
assigning credence 0.6 to \(p\) and credence 0.41 to
*not*-\(p\) - are plausibly structurally irrational.
Somewhat more controversially, failing to update one's credences
via conditionalization might be viewed as a kind of structural
irrationality between one's prior and posterior credences. The
latter case is more controversial, because this kind of
"incoherence" is typically understood as diachronic,
whereas some think that structural irrationality is a synchronic
phenomenon (see SS2.3). Consequently, viewing it as a kind of
incoherence either requires us to pinpoint some kind of synchronic
failure that occurs when one fails to conditionalize properly, or to
allow for diachronic instances of structural irrationality.



Let's now turn to forms of structural irrationality that (at
least partly) involve non-doxastic states. One paradigmatic example of
structural irrationality that we've already mentioned is
means-end incoherence (also known as 'instrumental
irrationality', though this term is sometimes used with other
meanings; see also the entry on
 instrumental rationality),
 whereby one intends to \(\Phi\), believes that in order to \(\Phi\)
one must \(\Psi\), but does not intend to \(\Psi\). Besides this,
perhaps the most common example of structural irrationality involving
non-doxastic states is practical akrasia - believing one ought,
all things considered, to \(\Phi\) but not intending to \(\Phi\) (see,
among many others, Broome 2001b, 2013; Kolodny 2005; for dissent, see
Arpaly 2000). Notably, this form of structural irrationality (as well
as means-end incoherence) involves incoherence between a belief and an
intention (or lack of), thus bridging doxastic and conative states.
Another example of a form of incoherence that bridges doxastic and
conative states might be intending to do something that one believes
one cannot do.



There are also plausible examples of structural irrationality that
obtain solely between conative states. It's often held that it
is structurally irrational to have contradictory intentions -
that is, to intend to \(\Phi\) and intend not to \(\Phi\). And as in
the doxastic case, there are forms of incoherence studied by
formally-inclined philosophers (and economists) that are naturally
thought of as instances of structural irrationality - such as
having cyclical preferences, whereby one prefers \(A\) to \(B\),
prefers \(B\) to \(C\), and yet prefers \(C\) to \(A\) (Davidson,
McKinsey and Suppes 1955; Gaus 2008: 36-40).



Finally - though this is understudied - there may be forms
of structural irrationality that involve affective and emotional
states (see also the entry on
 emotion,
 section 10). For example, perhaps it is structurally irrational to
hope for something that one believes to be bad, or to fear something
that one believes to be good. And perhaps it is also irrational to
hope for *or* fear something that one believes to be
impossible.


### 1.5 The Unity of Structural Rationality



As the above list makes clear, the instances of structural
irrationality are a diverse bunch. One may reasonably wonder what, if
anything, all these instances have in common. Some (e.g. Broome 2013)
seem to think that it is enough simply to say that they are all
combinations of states that are jointly irrational, but others aspire
to identify something deeper in virtue of which they share this
property.



One way of trying to do this is to embrace the reductivist view
mentioned in SS1.3 above. On this view, what structurally
irrational states have in common is that they are all combinations of
attitudes that cannot simultaneously be supported by one's
reasons. However, as we saw, this view faces some important
challenges, such as accounting for the structural irrationality of
sets of individually permissible attitudes. (It's worth noting
that there is another family of views that also, in a different way,
tries to explain structural rationality in terms of reasons. On these
views, what unifies structurally irrational states is that they
involve the agent's going against her *beliefs* about
reasons ("transparency" accounts), or her apparent reasons
("apparent reasons accounts"). We discuss these views, and
problems with them, in SS3.3.)



In a similar but somewhat different vein, some explore the idea that
attitudes are structurally irrational just in case they can't
all "succeed", or fulfil their "aim", where
this might be truth for beliefs and satisfaction or correctness for
intentions or preferences (Fink forthcoming; Fullhart and Martinez
forthcoming; see also Gibbard 2003; Brunero 2020: Ch. 7; Rosa 2022;
Singh forthcoming). However, this proposal struggles to explain the
incoherence of other mental states, such as credences. It is also far
from obvious that akratic attitude combinations cannot be jointly
successful - after all, the beliefs involved in epistemic
akrasia are logically consistent, and it is possible for a belief that
one ought to \(\Phi\) to be true even if the corresponding intention
is not satisfied. Proponents of this view are thus pressed to either
accept certain revisionary implications, to introduce more substantive
and hence more controversial success conditions for attitudes, or to
give up the ambition to provide a fully unifying account of structural
irrationality.



Another at least partially unifying proposal is
"cognitivism", which aspires to reduce certain structural
requirements governing intention (such as that of means-end coherence)
to certain structural requirements governing belief (such as that of
deductive closure) (Harman 1976; Velleman 1989; Wallace 2001; Setiya
2007). This view is premised on a corresponding cognitivism about
intention, on which, roughly, intending to \(\Phi\) involves believing
one will \(\Phi\). Given this, failures of means-end coherence (for
example) arguably result in one's violating closure -
specifically, violating a modus ponens requirement by believing one
will \(\Phi\), believing that one will \(\Phi\) only if one
\(\Psi\)-s, but not believing that one will \(\Psi\). As cognitivists
recognize (Setiya 2007), their account must be complicated or
supplemented to deliver this result. This is because even if intending
to \(\Phi\) involves believing that one will \(\Phi\), it
doesn't follow that *not* intending to \(\Psi\) involves
*not* believing that one will \(\Psi\) (perhaps one believes
that one will unintentionally \(\Psi)\). Moreover, the view that an
intention to \(\Phi\) involves believing one will \(\Phi\) has been
criticized (e.g., Bratman 2009a). Further, even if cognitivists are
right to think that means-end incoherence necessarily involves
doxastic incoherence, there are reasons to think that the former
involves a distinctively practical mistake that cannot be reduced to a
mistake in one's cognitive attitudes (e.g., Brunero 2020: Ch.
6). And finally, in our context, it is an open question whether
cognitivism can be a fully unifying theory of structural rationality,
as it is unclear how, for example, practical akrasia can be understood
as a violation of a purely doxastic structural requirements, or how
cognitivism delivers unity *within* the class of doxastic
structural requirements.



A proposal put forward by some formally-inclined philosophers is that
structurally irrational states are those that make one exploitable to
loss through devices such as Dutch books or money
 pumps.[4]
 However, again, this proposal seems insufficiently general to capture
all instances of structural irrationality: for example, there is no
obvious way in which someone with (either epistemically or
practically) akratic states is vulnerable to such loss. Moreover, even
where structural irrationality and exploitability coincide, it is
dubious whether it is the latter that explains the former, rather than
vice versa. Numerous philosophers have argued that one's
susceptibility to Dutch books or money pumps merely *reflects*
or *brings out* one's irrationality, rather than
grounding or explaining it, since it is unclear why vulnerability to
purely hypothetical monetary loss (that can only be exacted by someone
with full knowledge of one's mental states, and is almost
certain not to actually occur) is the right sort of thing to
*make* one irrational (Lewis 1999: 404-5; Christensen
2004: 109-24; Gaus 2008: 39; Levy 2014: 2).



Finally, it has recently been proposed that structurally irrational
states are unified by the fact that it is in some way difficult to
sustain them in full, reflective self-knowledge. On one version of
this proposal (Worsnip 2018b), this is because it is constitutive of
the mental states involved that to genuinely count as having these
states, one must have some disposition to revise them when these
conditions of "full transparency" are met. For example, if
one believes that to go shopping today one must get on one's
bike now, and does not intend to get on one's bike now, and one
is fully and consciously aware of both of these states and has no
disposition to revise them, then one arguably does not count as
intending to go shopping today (cf. also Finlay 2009; Lee 2022).
Again, though, this proposal faces some challenges. In particular, it
seems to force us to choose between denying that completely clear-eyed
practical akrasia is possible and denying that practical akrasia is
structurally irrational. It may also struggle with examples of
individuals who hold logically inconsistent or even contradictory
beliefs but are not disposed to revise them because they subscribe to
non-classical logics.


## 2. Requirements of Structural Rationality



A common assumption in the literature on structural rationality is
that agents have the property of being structurally rational or
irrational in virtue of satisfying or violating certain norms or
requirements of structural rationality (see esp. Broome 2013: Ch. 7).
This section is concerned with various disputes surrounding such
structural requirements. SSSS2.1-2.4 address questions
about the general form of structural requirements, while SS2.5 is
concerned with skepticism about structural requirements and with
approaches to structural rationality that dispense with structural
requirements. These disputes are important for anyone who aspires to
spell out a theory of structural rationality. They are also - as
we'll see in SS3 - relevant for debates about the
normativity of rationality.


### 2.1 Wide- vs. Narrow-Scope Requirements



The most widely debated - and arguably most important -
question about the form of structural requirements of rationality is
whether these requirements take wide scope (e.g. Broome 1999; Wallace
2001; Bratman 2009b) or narrow scope (e.g. Korsgaard 1997; Schroeder
2004; Kolodny 2005). To explain this distinction, recall that
structural irrationality involves (at least in the vast majority of
cases) a tension between at least two attitude-states (where an
attitude-state might consist in either the presence or the absence of
an attitude). For example, akrasia involves a tension between a belief
to the effect that one ought to \(\Phi\) \([\rBO\Phi]\) and the lack
of an intention to \(\Phi\) \([\rI\Phi].\) On the received view,
having this combination of attitude-states is irrational in virtue of
violating a requirement of structural rationality. And on a *prima
facie* natural interpretation of such requirements, these
requirements are conditional on one (or more) of the relevant
attitude-states (the "antecedent state(s)") and take scope
over some other attitude-state (the "consequent state").
Thus, for example, a natural way to understand what Broome (2013) has
dubbed the "enkratic requirement" - the requirement
prohibiting akrasia - is as follows:



*Enkratic requirement, narrow-scope:*
  

If \(A\) believes that she ought to \(\Phi\), then rationality
requires \(A\) to intend to \(\Phi\) \([\rBO\Phi \to
\rR(\rI\Phi)].\)



As several authors have emphasized, however, structural requirements
can also be understood in a different way (Hill 1973; Greenspan 1975;
Dancy 1977; Darwall 1983; and, more recently, Broome 1999, 2007c,
2013; Wallace 2001; Bratman 2009b; Brunero 2010, 2020; Way 2011).
According to this alternative reading, structural requirements are not
conditional on the antecedent state; instead, both the antecedent and
the consequent state are part of the scope of requirement, which is
why this is called a 'wide scope' reading. In case of the
enkratic requirement, this interpretation says:



*Enkratic requirement, wide-scope:*
  

Rationality requires of \(A\) that [if \(A\) believes that she ought
to \(\Phi\), then \(A\) intends to \(\Phi\)]
\([\rR(\rBO\Phi\to\rI\Phi)]\).



To illustrate the relevance of this distinction and the ways in which
the two requirements have different consequences, consider Ava, an
environmentalist activist who has gone astray and formed the belief
that she ought to extinguish all human life. The narrow-scope and
wide-scope enkratic requirements will have different results for our
verdicts about Ava along two dimensions: *symmetry* and
*detachment*.



Beginning with symmetry: Ava can comply with the wide-scope enkratic
requirement in one of two ways: either by coming to intend to
extinguish human life or by dropping her belief that she ought to
extinguish human
 life.[5]
 Conversely, she can comply with the narrow-scope enkratic requirement
only by coming to intend to extinguish human life. In this sense, the
wide-scope requirement is *symmetric* while the narrow-scope
requirement is *asymmetric*. Strikingly, this difference has
been employed as part of arguments for *both* the wide-scope
and narrow-scope views. Wide-scopers claim that symmetry is desirable
because it would not be irrational in any good sense for Ava to drop
her misguided belief instead of coming to intend to extinguish human
life (Broome 1999; Worsnip 2021). Narrow-scopers, by contrast, charge
that symmetry is undesirable because there is an important difference
between forming an intention *on the basis* of a normative
belief and dropping a normative belief merely *on the basis of*
an absence of an intention to follow through on it: the former process
seems in some way more rational than the latter (Schroeder 2004, 2009;
Kolodny 2005; Bedke 2009; Finlay 2010). Whether this latter charge is
a compelling argument against the wide-scope view depends in large
part on whether structural requirements such as the enkratic
requirement should reflect facts about which states it is rational to
*base* on which: Kolodny (2005) argues that they must, while
many wide-scopers (Way 2011; Brunero 2012; Broome 2013) hold that they
do not, maintaining that there are independent "basing
prohibitions" and "basing permissions" that account
for the rationality of basing in particular.



Let's now consider detachment. Consider the inference:



(1a)
\(\rBO\Phi\to \rR(\rI\Phi)\)
(2)
\(\rBO\Phi\)
So,
 
(3)
\(\rR(\rI\Phi)\)


This inference-pattern is valid via *modus ponens*. Applied to
the case of Ava, this means that we can derive (or
"detach") a requirement for Ava to intend to extinguish
human life (3) from the narrow-scope enkratic requirement (1a) and the
premise that Ava believes that she ought to extinguish human life (2).
The wide-scope account avoids this implication, for the following
inference is not validated by the propositional calculus:



(1b)
\(\rR(\rBO\Phi\to\rI\Phi)\)
(2)
\(\rBO\Phi\)
So,
 
(3)
\(\rR(\rI\Phi)\)


Hence, the conclusion that Ava is rationally required to intend to
extinguish all human life (3) does not obviously follow from the
wide-scope enkratic requirement (1b) and the premise that Ava believes
that she ought to extinguish all human life (2). In order for this
inference to be valid, the deontic logic of rational requirements
would need to contain the following axiom:



*Factual detachment:*
  

If \(p\), and rationality requires of \(A\) that \(p\to q,\) then
rationality requires of \(A\) that \(q\).



But this principle is questionable and widely rejected (see esp.
Broome 1999).



Some philosophers (e.g., Broome 1999; Bratman 2009b) take the fact
that narrow-scope requirements detach while wide-scope requirements do
not as a point in favor of the wide-scope requirement. Suppose that we
have derived the conclusion that Ava is rationally required to intend
to extinguish all human life from the narrow-scope enkratic
requirement via modus ponens. If we add the further premise that
rationality is normative (see SS3 below) in the sense that we
ought (or have reason) to comply with structural requirements, we are
forced to conclude that Ava *ought* (or has reason) to intend
to extinguish all human life - simply because she has adopted a
crazy belief. But this kind of "bootstrapping" is widely
regarded as unacceptable (recall SS1.1). Thus, if rationality is
normative, this seems to tell against the narrow-scope view.



It is worth noting that the issues of symmetry, detachment, and
bootstrapping arise with regard to the scope of all structural
requirements on attitude-combinations, including those that concern
only doxastic states. For one example, take the aforementioned
(putative) requirement forbidding "epistemic akrasia",
which requires alignment between one's higher-order and
first-order doxastic states. Suppose Darren believes that his evidence
supports believing that the earth is flat. Again, a narrow-scope
version of an anti-epistemic akrasia requirement seems to allow us to
detach the conclusion that (structural) rationality requires Darren to
believe that the earth is flat. Wide-scopers will complain that this
is incorrect, since structural rationality should at least permit
Darren to instead drop his higher-order belief that the evidence
supports believing that the earth is flat (i.e., the requirement
should be symmetrical). Moreover, they will say, it is particularly
objectionable when paired with the thesis that rationality is
normative, since this would allow us to conclude that Darren can make
it the case that he ought or has reason to believe the earth is flat
merely by (unjustifiably) believing that this is what his evidence
supports (i.e., would license problematic bootstrapping). On the other
hand, narrow-scopers will charge that it is more rational to come to
believe \(p\) on the *basis* of a belief that one's
evidence supports \(p\) than to drop a belief that one's
evidence support \(p\) on the *basis* of a mere absence of
belief in \(p\). Or consider the requirement to respect *modus
ponens*, and our aforementioned character Ali, who believes he is
Superman and that Superman can fly. Wide-scopers will hold that
structural rationality should at least permit Ali to drop his belief
that he is Superman rather than come to believe he can fly. In
addition, they will stress that any view that yields the conclusion
that Ali can make it the case that he ought or has reason to believe
he can fly merely by holding the beliefs that he is Superman and that
Superman can fly must be rejected. By contrast, narrow-scopers will
hold that it is more rational to come to believe \(q\) on the basis of
belief in \(p\) and belief that if \(p\) then \(q\) than it is to give
up one's belief in \(p\) or one's belief that if \(p\)
then \(q\) on the basis of a mere *absence* of belief in \(q\)
(as distinct from a positive belief that not-\(q)\). (For reasons of
brevity, we will focus on the practical enkratic requirement in the
remainder of this section, but as with this subsection, the same
points apply to other structural requirements, including those that
concern only doxastic states.)



The wide-scope account has sometimes been charged with assuming a
mistaken *semantic* view, namely that ordinary conditionals of
the form "If you \(\Phi\), you ought to \(\Psi\)" are to
be read as really expressing the wide-scope requirement that you ought
to be such that (if you \(\Phi\), then you
 \(\Psi)\).[6]
 Many philosophers of language reject this "wide-scope
semantics" (Hansson 1969, van Fraassen 1972, Lewis 1973, Kratzer
1981; for applications to contemporary debates about rationality, see
Dreier 2009, Schroeder 2011, Dowell 2012, Silk 2014). In response,
wide-scopers can make two points (Kiesewetter 2017: Ch. 3; Worsnip
2021: Chs. 6-7). First, they can maintain that while the
fundamental explanation of structural irrationality is provided by
wide-scope requirements, the semantics of ordinary conditionals is a
different matter. For example, Worsnip (2021: Ch. 7) combines the
wide-scope view of structural requirements with a more orthodox,
contextualist account of ordinary deontic conditionals along the lines
of Kratzer (1981). Second, they can point out that the spirit of the
wide-scope view can be maintained without stating structural
requirements as involving conditionals at all. The relevant
requirements can instead be understood as requiring disjunctive
responses or as prohibitions on combinations of responses. For
example, the wide-scope enkratic requirement can be formulated in
either of the following two ways:



*Enkratic requirement, disjunctive:*
  

Rationality requires \(A\) to [intend to \(\Phi\) or not believe that
she ought to \(\Phi\)].



*Enkratic requirement, combination prohibition:*
  

Rationality requires \(A\) to not [believe that she ought to \(\Phi\)
and not intend to \(\Phi\)].



These requirements are symmetric and do not allow for detachment; they
thus share with the original wide-scope formulations the properties
that distinguish them from narrow-scope requirements.


### 2.2 Synchronic vs. Diachronic Requirements



As we have discussed them so far, structural requirements do not index
attitude-states to time points and are thus open to two
interpretations. On the *synchronic* interpretation, all the
attitude-states are indexed to the same point in time, while on a
*diachronic* interpretation, the attitude-states are indexed to
different time points or periods. For example, the narrow-scope
enkratic requirement (SS2.1) may be understood in either of the
following ways:



*Enkratic requirement, narrow-scope + synchronic:* If \(A\)
believes at \(t\) that she ought to \(\Phi\), rationality requires
\(A\) to intend at \(t\) to \(\Phi\).



*Enkratic requirement, narrow-scope + diachronic:* If \(A\)
believes at \(t\_1\) that she ought to \(\Phi\), rationality requires
\(A\) to intend at \(t\_2\) to \(\Phi\).



The literature contains two kinds of arguments for the diachronic
approach. The first is that only diachronic requirements can guide our
reasoning going forward (Schroeder 2004; Kolodny 2005). The second is
that synchronic requirements cannot accommodate "rational
delay" - the assumption that limited beings like us are
not rationally criticizable for taking time to adjust their attitudes
to new circumstances and establish coherence (Kiesewetter 2017:
62-70; Podgorski 2017).



However, it is difficult to spell out diachronic requirements. An
important challenge for any diachronic approach is to specify the
relation between \(t\_1\) and \(t\_2\). A possible view is that \(t\_2\)
is just any time after \(t\_1\), perhaps even including \(t\_1\) (Lord
2014). While this might speak to the guidance-related argument for the
diachronic account, it does not seem appropriate as a response to the
phenomenon of rational delay. And since the length of rational delay
appears to depend on particular circumstances and individual
abilities, there is reason to be skeptical that there could be a
principled specification of diachronic requirements that accounts for
rational delay.



Moreover, if one is persuaded that the wide-scope approach is superior
to the narrow-scope approach, there are further problems for the
diachronic approach, as it is debatable whether the diachronic
approach is consistent with the spirit of the wide-scope approach.
Consider:



*Enkratic requirement, wide-scope + diachronic:* Rationality
requires \(A\) to (not-believe at \(t\_1\) that she ought to \(\Phi\)
or intend at \(t\_2\) to \(\Phi)\).



If \(A\) believes at \(t\_1\) that she ought to \(\Phi\), then at
\(t\_2\) intending to \(\Phi\) is the only way in which \(A\) can
satisfy this requirement. Thus, a requirement to adopt this intention
can plausibly be detached (Broome 2013). This violates the spirit of
the wide-scope approach. While other ways of spelling out diachronic
wide-scope requirements have been proposed, it remains controversial
whether they can preserve symmetry and non-detachability without
collapsing into their synchronic counterparts (Lord 2014; Reisner
2009; Kiesewetter 2017: 58-69; Worsnip 2021: 183-7).



While there is considerable disagreement about whether all structural
requirements are diachronic, it is somewhat less controversial that
there are at least some essentially diachronic requirements of
rationality - for example, requirements of *attitude
persistence* that prohibit abandoning beliefs or intentions
arbitrarily (Broome 2013; Bratman 2018; Brunero 2022). However, at
least in the doxastic realm, some authors have argued that there are
no diachronic requirements at all (Hedden 2015; Moss 2015).


### 2.3 Process vs. State Requirements



While most authors take requirements of structural rationality to
govern attitude-states, such as beliefs or intentions, some have
argued that they should rather be understood as requirements on
processes, such as reasoning or, more generally, the *forming*,
*dropping* or *retaining* of attitudes (Kolodny 2005,
2007b; Podgorski 2017). Since processes are temporally extended, all
process requirements are diachronic. What is less often recognized is
that the reverse is not true: diachronic requirements need not be
process-requirements, since they can govern *states* at
different points in time (Podgorski 2017). Thus, the
synchronic/diachronic debate is distinct from the process/state
debate.



In support of the process-oriented view, Kolodny (2005) holds that
requirements can be response-guiding and potentially normative
(SS2.2) only if they govern processes rather than states. He also
argues that state-requirements are redundant once all plausible
process requirements have been specified. Critics of the
process-oriented view have responded by drawing an analogy to
*reasons* for belief and other attitudes, which can be
response-guiding and normative even though they are for states rather
than processes, and have challenged Kolodny's redundancy claim
(Kiesewetter 2017: 73-79).



While it is very controversial whether all instances of structural
irrationality can be explained in terms of process requirements, it is
less controversial that there *are* process requirements that
cannot be reduced to state requirements. For example, what seems
irrational about wishful thinking is not necessarily the belief or the
wish, or the combination of these states, or their occurrence in a
certain chronological order, but specifically the *process*
through which the belief was formed. More generally, it seems
plausible that there are *basing* prohibitions (Broome 2013)
- rational requirements not to *base* certain attitudes
on others - which cannot be reduced to state-requirements.


### 2.4 Skepticism about and Alternatives to Requirements of Structural Rationality



A number of authors have raised skepticism about structural
requirements of rationality. We will distinguish three varieties of
such skepticism.



The first variety, which we call "impossibilist
skepticism", is based on the view that once one specifies
sufficient conditions for structural irrationality, it turns out to be
impossible to violate these conditions. The idea that it is impossible
to violate at least some putative structural requirements has a long
history: the Socrates of Plato's *Protagoras* denies the
possibility of akrasia (see also Davidson 1969 and the entry on
 weakness of will),
 while other authors have denied the possibility of *epistemic*
akrasia specifically (Hurley 1989; Adler 2002), irrational
self-contradiction (Price 2008), and instrumental irrationality
(Finlay 2009; Timmermann 2022). Impossibilist skeptics combine the
premise that the putative structural requirements are inviolable with
the further premise (argued for by Korsgaard 1997, among others) that
any genuine requirement of rationality must leave room for violation,
to yield the conclusion that the putative structural requirements are
not genuine rational requirements after all (Finlay 2009; Lee
2022).



Impossibilist skepticism entails not only that there are no structural
*requirements* of rationality, but also that there is no such
thing as a property of structural rationality (understood as a
property that people can fail to have). By contrast, a second kind of
skepticism, which we call "particularist skepticism", does
not necessarily take issue with this property; it merely denies that
the occurrence of structural irrationality can be explained in terms
of *general* structural requirements. Proponents of this view
hold that all general structural requirements prohibiting
attitude-combinations are subject to counterexamples, for example in
cases of luminosity failure (i.e. failure to be in a position to know
one's own attitudes) and cases in which subjects have
higher-order beliefs or evidence that conflict with the putative
requirement (Fogal 2020; Lasonen-Aarnio 2021).



In place of the requirements-based approach, particularist skeptics
offer alternative models. For example, Fogal (2020) suggests a
"pressure-based" model, on which attitudes exert a
gradable rational pressure (analogous to the normative pressure of
*pro tanto* reasons) and the structural rationality or
irrationality of an attitude depends on the greatest positive or
negative rational pressure overall. By contrast, Lasonen-Aarnio (2021)
proposes to explain the irrationality of incoherence in terms of the
manifestation of certain bad dispositions - dispositions that
conflict with being a competent follower of substantive norms (for a
similar view, see also Raz 2005). Both views avoid a commitment to
generalizable truths to the effect that certain sets of attitudes are
by themselves sufficient for irrationality.



A third kind of skepticism, which we call "substantivist
skepticism", holds that even if extensionally adequate
formulations of general structural requirements are available, the
assumption that there are such requirements is dispensable since
structural irrationality can be explained in terms of requirements of
*substantive* rationality
 alone.[7]
 (We mentioned this reductive view already in SS1.3.) Proponents
of substantivist skepticism often hold that we should dispense with
structural requirements if we can because they are problematic. For
example, some hold that such requirements cannot be normative (see
SS3) but would have to be normative in order to exist at all
(Price 2008; Kiesewetter 2017: Ch. 2, and Ch. 6 for some additional
undesirable implications of structural requirements).


## 3. The Normative Significance of Structural Rationality



It is widely held that ascriptions of irrationality involve a certain
kind of criticism and, thus, that truths about rationality or
irrationality are, or at least appear to be, normative or normatively
significant (e.g. Parfit 2001; Kolodny 2005; Broome 2007b; Scanlon
2007). A natural (and dominant) way to spell out this intuition is to
say that there necessarily are normative reasons to conform to
rational requirements. But while it seems evident that there
necessarily are reasons to conform to *substantive*
requirements (at least on standard conceptions of substantive
rationality), it is much less clear why this should be so in the case
of structural requirements. In this section, we give an overview of
the most important challenges for the assumption that there
necessarily are reasons to conform to structural requirements and
discuss the major theoretical options that one can adopt with respect
to the normativity of rationality more generally.


### 3.1 Bootstrapping and Detachment



Perhaps the most widely discussed challenge for the normativity of
structural rationality is the worry that the assumption of reasons for
conforming to structural requirements would license implausible forms
of "bootstrapping" or detachment (see esp. Bratman 1981,
Broome 2001a, Kolodny 2005, and cf. SS1.1 above). As we already
saw in SS2.1, a narrow-scope account of structural requirements
plus the assumption that rationality is normative seems to yield
unacceptable bootstrapping. For example, it suggests that merely by
believing that she ought to extinguish all human life, Ava can
make it the case that she ought to, or at least has reason to, intend
to extinguish all human life. As we again saw in SS2.1, some take
this as an objection to the narrow-scope view. Others, however, take
it as an argument that structural rationality cannot be normative
(Kolodny 2005).



In support of the latter way of going, some have argued that a
normative interpretation of structural requirements licenses
implausible detachment even on the wide-scope view. Such arguments
typically appeal to certain transmission principles - which are
(roughly speaking) principles about how reasons are transmitted from
ends to means (see also the entry on
 instrumental rationality,
 section 2). A prominent instance is Raz's argument against the
wide-scope instrumental requirement (Raz 2005). The argument is based
on what is sometimes called a "liberal" principle of
reasons transmission, which says (roughly) that for every means that
facilitates or probabilizes doing what we have reason to do, there is
a derivative reason to take this means (Raz 2005; Bedke 2009; Kolodny
2018). Because wide-scope requirements are symmetric, both dropping
the antecedent attitude-state as well as adopting the consequent
attitude-state are (highly effective) means to conforming to the
requirement. Therefore, if there is a reason to conform to wide-scope
requirements, it follows from the liberal transmission principle that
we can detach a reason to adopt the consequent attitude-state (as well
as a reason to drop the antecedent attitude-state). Again, we end up
with the unwanted result that Ava has a reason to intend to extinguish
all human life. If this argument is sound, opting for a wide-scope
rather than a narrow-scope account of structural requirements does not
avoid the problem with detachment. However, some reject the liberal
transmission principle on which the argument is based, at least in
full generality (Broome 2005; Way 2010; Rippon 2011; Kiesewetter and
Gertken 2021).



A different argument to the effect that even wide-scope normative
requirements of structural rationality license implausible detachment
is based not on the liberal transmission principle, but on the weaker
principle that reasons transmit to *necessary* means (Setiya
2007, who partly draws on Greenspan 1975). The problem is that an
agent may be psychologically incapable of altering one of her
antecedent attitudes, which renders adopting the consequent attitude a
necessary means for conforming to the wide-scope requirement. For
example, if Ava is unable to give up her belief that she ought to
extinguish all human life, then intending to extinguish all human life
is a necessary means to conforming to the wide-scope enkratic
requirement. Thus, if Ava has reason to conform to this requirement,
the necessary means transmission principle entails that we can detach
a reason to intend to extinguish all human life once again. As before,
however, some reject the transmission principle on which this argument
is based (Broome 2013; but see Kiesewetter 2015 for replies). Others
(Bratman 2009b) have replied to the argument by suggesting that the
general reason to satisfy structural requirements - which in
Bratman's view, is one of self-governance - is not
operative in cases where the agent is psychologically unable to alter
their attitudes (but see Brunero 2010; 2020: Ch. 5; Kiesewetter 2017:
Ch. 5 for challenges for Bratman's view).


### 3.2 The Why-Be-Rational Challenge



A second major difficulty for the view that there necessarily are
reasons to conform to structural requirements is to come up with a
satisfying answer to the question "Why be rational?"
(Kolodny 2005) - an answer that explicates what such
reasons consist in and justifies the assumption that they
 exist.[8]
 It is worth noting that this challenge applies to requirements of
*structural* rationality in particular. At least if
requirements of substantive rationality are understood in terms of
facts about the balance of reasons, it makes no sense to ask what
reasons we have to conform to such requirements: there is no need for
a reason to do what there is reason to do. But since structural
requirements are not to be understood in terms of facts about the
balance of reasons, it is a fair question why one should conform to
them.



It is natural to think that an answer to the why-be-rational challenge
must show how one can derive a reason to conform to structural
requirements from other reasons that exist independently of structural
rationality. According to this *derivative approach*, there is
reason to satisfy structural requirements because doing so is
conducive to (or necessary for) - for example - being an
agent (Korsgaard 2009), governing oneself (Bratman 2009b), doing what
is objectively choiceworthy (Wedgwood 2017), or being interpretable by
others (Mildenberger 2019). Proposals of this form are subject to at
least one of two potential objections. One might question that
structural rationality is in fact necessarily conducive to (or
necessary for) the other relevant property, and one might question
that there necessarily is a reason to instantiate this other property
(Kolodny 2005; Broome 2007b; Kiesewetter 2017; Brunero 2020). The
current state of the literature tends towards the verdict that none of
the existing proposals has been shown to be immune against both kinds
of objections.



Partly in response to problems for the derivative approach, some of
those who are sympathetic to the normativity of structural rationality
have opted for a *non-derivative approach*, according to which,
for any structurally irrational combination of attitudes, there is a
*sui generis* "reason of [structural] rationality"
to avoid them, constituted by the very fact that the attitudes in
question are prohibited by structural rationality (Southwood 2008; see
also Broome 2013; Hussain 2007 - see Other Internet Resources).
This move is often supported by way of an analogy with H.A.
Prichard's influential response to the why-be-moral challenge,
which essentially involved the rejection of the idea that morality
could be derivatively justified (Prichard 1912). Critics of the
non-derivative approach respond that it seems fetishistic to treat
structural rationality as something we have reason to aim at *for
its own sake* (Kolodny 2005) and that the alleged normativity of
structural rationality lacks the kind of self-evident status that
Prichard claims for the moral case and bases his view on (Brunero
2020).



Besides the objections that apply to the derivative and the
non-derivative approaches specifically, Kolodny (2005) also has raised
an important general challenge for the assumption that there
necessarily is a reason to do what satisfies structural requirements.
On the most general level, the problem is that it is unclear what
deliberative relevance such a reason could have. Typically, we form
attitudes on the basis of considerations connected to their
*correctness* rather than their *coherence* with other
attitudes. For example, we adopt beliefs because we think they are
supported by evidence rather than because they cohere with our other
beliefs. Indeed, it seems that because of their
correctness-independence, coherence-based reasons for attitudes would
belong to the category of so-called "wrong-kind
 reasons".[9]
 The existence of wrong-kind reasons is often denied (e.g. Kolodny
2005; Way 2016), and even those who accept their existence typically
agree that such reasons are irrelevant for the rationality of
attitudes (Schroeder 2012). It would thus be very surprising if the
normativity of certain rational requirements depended on such reasons.
(See Worsnip 2021: Ch. 8 for a recent defense of the view that the
normativity of structural rationality can be understood in terms of
*right*-kind of reasons, and Daoust 2022 and Kiesewetter 2023
for criticism.)


### 3.3 Transparency and Apparent Reasons Accounts



If there are not necessarily reasons to conform with requirements of
structural rationality, this raises the questions of whether there is
some other interesting relation between structural rationality and
reasons, and whether there is an explanation of why it has seemed to
many that structural rationality is normatively significant. Two
prominent views in the literature on rationality - the
transparency account and the apparent reasons account - provide
answers to these questions.



According to the *transparency account,* structural rationality
is a matter of coherence between one's attitudes and one's
normative beliefs about such attitudes, and for an attitude to be
required by structural rationality is for one to have a belief that
this attitude is supported by conclusive reasons (Kolodny 2005, and on
one reading, Scanlon 2007). On this view, the apparent normativity of
structural rationality is due to the fact that from the first-personal
standpoint, rationally required attitudes are always *believed*
to be supported by conclusive reasons.



The transparency account faces problems, however. First, the normative
appearance of rationality is not limited to the first-personal
perspective. We seem to presuppose that rationality is normatively
significant when we *recommend* options as rational or
*criticize* responses as irrational, and the hypothesis that
rationally required responses must be *believed* to be
normatively supported *by the agent for whom they are required*
does not help to understand this (Bridges 2009; Hussain 2007 -
see Other Internet Resources). Second, the assumption that structural
irrationality always involves a conflict between an attitude and a
normative belief about that attitude is questionable: a number of
plausible instances of structural irrationality - in particular
those involved in certain forms of belief inconsistency and means-end
incoherence (see SS1.4) - do not seem to involve such a
conflict.



While the transparency account explains rationality in terms of
believed reasons, the apparent reasons account explains rationality in
terms of "apparent reasons", which are usually understood
as the reasons we *would* have if our beliefs were true (e. g.
Parfit 2011; Schroeder 2009; Way 2009; Whiting 2014; Alvarez 2018; see
also Sylvan 2015 for a more sophisticated conception of apparent
reasons). It has been stated as the view that "for you to be
rationally required to \(A\) is for it to be the case that you would
have conclusive reasons to \(A\), if your beliefs were true"
(Way 2009, 4). Parfit (2001) first proposed a view along these lines,
arguably as an account of *substantive* rationality. However,
several authors have tried to explain structural rationality (and, by
extension, its apparent or actual normative force) in terms of
apparent reasons as well (Schroeder 2009; Way 2012; Sylvan 2021a).



Some proponents of the apparent reasons account suggest that
rationality is in fact normative on their view. For example, Schroeder
(2009) identifies rational requirements with "subjective
oughts", which he takes to be genuinely normative, and Parfit
claims that "normativity involves reasons or apparent
reasons" (2011, 59). According to Way (2009), the apparent
reasons account vindicates the normativity of rationality, because it
explains rational requirements in terms of hypothetical truths of the
form 'If your beliefs were true, you would have conclusive
reason to A' - and such truths are in an interesting sense
normative, as a normative error theorist is committed to denying them.
However, critics have contended that the sense in which hypotheticals
about reasons are normative is a merely technical one that does
nothing to vindicate the *actual* normative significance of
rationality (Kiesewetter 2012). (For more on the normative relevance
of apparent reasons, see Gonzalez de Prado Salas 2018; Sylvan
2021a).)



The apparent reasons account also faces similar challenges as the
transparency account when it comes to accounting for kinds of
structural irrationality that do not involve attitudes with normative
contents. While it is straightforward that akratic agents go against
what would be conclusive reasons if their beliefs were true, it is
much more difficult to see that this is true for agents with
"formally incoherent" attitudes, such as incoherent
credences.


### 3.4 The Theoretical Options



To summarize, the debate on the normativity of rationality is often
centred around two theoretical options. One is to preserve the
normativity of rationality by defending the claim that there
necessarily are reasons to conform to structural requirements. The
other is to deny this claim, and abandon the view that rationality is
normative. As we have seen, both options face significant challenges.
Proponents of the first view must explain why their views do not
entail implausible forms of detachment, why the reasons they allude to
exist, and why they are of the right kind. Proponents of the second
view must explain why rationality seems normative when it isn't.
More specifically, proponents of the second view need to explain both
why describing someone as irrational amounts to a serious form of
criticism if there is no reason to avoid irrationality, and how
requirements of structural rationality can count as
*requirements* if there's no sense in which we have
reason to comply with them (and if they also aren't
"institutional" or "positive" requirements
like the requirements of a social club or 19th century
etiquette). In addition, they face an especially strong challenge to
say what unites structural requirements as such, as they cannot to
account for the unity of structural rationality by appeal to the
reasons that support it.



There is a third option to deal with the issues discussed in this
section, which is to dispense with structural requirements of
rationality (SS2.4) and adopt the view (briefly discussed in
SS1.3) that structural irrationality is to be explained in terms
of substantive requirements of rationality, understood as requirements
to respond correctly to reasons, alone. As its proponents have
emphasized, this view has the benefits of preserving the idea that
rationality is normative, while avoiding the problems that arise with
assuming that there are reasons to comply with structural
requirements. It is not troubled by detachment worries and can dismiss
the why-be-rational challenge as an illegitimate request for a reason
to do what we have reason to do. It is well-positioned to explain the
criticizability of irrationality and the unity of rationality. But as
we have seen already, it faces its own challenges. As noted at the
beginning of this entry (SS1.1), distinguishing between reasons
and requirements of structural rationality gave us a way to explain
how one's holding one attitude can make it the case that one
holds another attitude, one is irrational, *without* allowing
the attitudes one has (no matter how misguided) to dictate what
substantive reasons one has. Whether a theory that operates only with
requirements of substantive rationality can do this is still a
controversial question.



Thus, despite the now-voluminous literature on structural rationality,
there remain deep challenges for all the views that have been
identified. How one adjudicates the comparative seriousness of these
challenges will affect whether one opts for a theory of rationality
that includes normative structural requirements, non-normative
structural requirements, or no structural requirements at all.