It is a popular view thatpractical deliberation excludes foreknowledge of one's choice. Wolfgang Spohn and Isaac Levi have argued that not even a purely probabilistic self-predictionis available to thedeliberator, if one takes subjective probabilities to be conceptually linked to betting rates. It makes no sense to have a betting rate for an option, for one's willingness to bet on the option depends on the net gain from the bet, in combination with the option's antecedent utility, rather than on the offered (...) odds. And even apart from this consideration, assigning probabilities to the options among which one is choosing is futile since such probabilities could be of no possible use in choice. The paper subjects these arguments to critical examination and suggests that, appearances notwithstanding, practical deliberation need not crowd outself-prediction. (shrink)

Extended Rationality: A Hinge Epistemology provides a novel account of the structure of epistemic justification. Its central claim builds upon Wittgenstein's idea in On Certainty that epistemic justifications hinge on some basic assumptions and that epistemic rationality extends to these very hinges. It exploits these ideas to address major problems in epistemology, such as the nature of perceptual justifications, external world skepticism, epistemic relativism, the epistemic status of basic logical laws, of the Principle of the Uniformity of Nature, of our (...) belief in the existence of the past and of other minds, and the nature of testimonial justification. Along the way, further technical issues, such as the scope of the Principle of Closure of epistemic operators under known entailment, the notion of transmission failure, and the existence of entitlements are addressed in new and illuminating ways. (shrink)

What is structural rationality? Specifically, what is the distinctive feature of structural requirements of rationality? Some philosophers have argued, roughly, that the distinctive feature of structural requirements is coherence. But what does coherence mean, exactly? Or, at least, what do structuralists about rationality have in mind when they claim that structural rationality is coherence? This issue matters for making progress in various active debates concerning rationality. In this paper, I analyze three strategies for figuring out what coherence means in the (...) debates on structural rationality. I argue that these strategies face problems. (shrink)

Epistemic akrasia arises when one holds a belief even though one judges it to be irrational or unjustified. While there is some debate about whether epistemic akrasia is possible, this paper will assume for the sake of argument that it is in order to consider whether it can be rational. The paper will show that it can. More precisely, cases can arise in which both the belief one judges to be irrational and one’s judgment of it are epistemically rational in (...) the sense that both are supported by sufficient evidence. (shrink)

I argue that inferences from highly probabilifying racial generalizations are not solely objectionable because acting on such inferences would be problematic, or they violate a moral norm, but because they violate a distinctively epistemic norm. They involve accepting a proposition when, given the costs of a mistake, one is not adequately justified in doing so. First I sketch an account of the nature of adequate justification—practical adequacy with respect to eliminating the ~p possibilities from one’s epistemic statespace. Second, I argue (...) that inferences based on demographic generalizations tend to disproportionately expose group members to the risks associated with mistakenly assuming stereotypical propositions, and so magnify the wrong involved in relying on such inferences without adequate justification. (shrink)

Constitutivist approaches to the normativity of rationality have recently come into vogue. Unlike their moral counterparts, however, they have not been confronted with the shmagency objection. In this paper, I challenge them with two versions of the objection based on recent developments in the debate surrounding the normativity of morality. These are shmagency as modal escapability, which is based on taking sophisticated shmagents to be able to modally escape various norms, and shmagency as underdetermination, which is based on taking constitutive (...) norms that allegedly have independent value to be underdetermined by that value. I consider three different kinds of constitutivist theories of the normativity of rationality: first-person-authority views, single-mental-state views, and systems-of-mental-states views. None of the three are able to deal with either of these shmagency objections. There are sophisticated shmagents who escape all these types of constitutivist principles of rationality, so they are modally escapable, and the value of rationality underdetermines all the views. Upshot: constitutivists about structural rationality ought to worry about shmagency. (shrink)

SummaryNeither an infant one week old nor a snail is a rational creature. If the infant survives long enough, he will probably become rational, while this is not true of the snail. If we like, we may say of the infant from the start that he is a rational creature because he will probably become rational if he survives, or because he belongs to a species with this capacity. Whichever way we talk, there remains the difference, with respect to rationality, (...) between the infant and the snail on one hand, and the normal adult person on the other; this difference is discussed here.The difference consists, it is argued, in the having of propositional attitudes such as belief, desire, intention and shame. This raises the question how to tell when a creature has propositional attitudes; snails, we may agree, do not, but how about dogs or chimpanzees? The question is not empirical; the question is what sort of empirical evidence is relevant to deciding when a creature has propositional attitudes.It is next contended that language is a necessary concomitant of any of the propositional attitudes. This idea is not new, but there seem to be few arguments in its favor in the literature; one is attempted here.Crucial to the considerations advanced is the idea that belief depends on having the concept of objective truth, and that this comes only with language.RéuméNi un bébé d'une semaine, ni un serpent ne sont des créatures rationnelles. Si le bébé survit assez longtemps, il deviendra probablement rationnel, mais ce n'est pas vrai pour le serpent. Sil'on veut, on peut dire d'emblee du bébé qu'il est une créature rationnelle parce qu'il le deviendra s'il survit ou parce qu'il appartient à une espèce qui possède cette faculté. Quoi qu'on dise, la différence subsiste, en ce qui concerné la rationalité, entre le bébé et le serpent d'une part, la per‐sonne adulte normale de lcar;autre, et c'est cette différence qui sera discutée ici.La différence consiste, selon l'auteur, en une capacityé d'avoir des attitudes propositionnelles telles que la croyance, le désir, l'intention et la honte. Ceci pose la question de savoir quand on peut dire qu'une créature a des attitudes propositionnelles; on peut se mettre d'accord sur le fait que les serpents n'en ont pas, mais qu'en est‐il des chiens et des chimpanzés? La question n'est pas empirique, elle est de savoir quelle donnée empirique va décider si oui ou non une créature a des attitudes propositionnelles.L'auteur prétend que les attitudes propositionnelles s'accompagnent nécessairement du langage. Cette idèe n'est pas nouvelle, mais il semble qu'il y a peu d'arguments qui la soutiennent dans la littérature. On en trouvera un ici, où l'on montre qu'un élément crucial de a croyance dépend de l'acquisition du concept de vérité objective, qui ne se développe qu'avec le langage.ZusammenfassungWeder ein eine Woche altes Kind noch eine Schlange sind rationale Wesen. Wenn das Kind lange genug überlebt, wird es sich wahrscheinlich zu einem vernünftigen Wesen entwickeln, wäh‐rend das für die Schlange nicht zutrifft. Wenn wir wollen, können wir vom Kind sagen, dass es von Anfang an cin rationales Wesen ist, weil es im Fallc des Ubcrlebens vernünftig werden wird oder weil es zu einer Spezies mit dieser Fähigkeit gehört. Wie auch immer wir das ausdrücken, bleibt bezüglich der Rationalität der Unterschied zwischen dem Kind und der Schlange einerseits und der erwachsenen Person andererseits zurück. Dieser Unterschied wird hier diskutiert.Es wird argumentiert, dass der Unterschied in der Fähigkeit besteht, psychologische Haltun‐gen wie Glauben, Begierden, Absichten und Scham zu haben. Damit erhebt sich die Frage, wie man entscheiden kann, wann ein Wesen solchc Einstellungcn hat; Schlangen, wird man zugeben, haben keine; wie steht es aber mit Hunden Oder Schimpansen? Die Frage ist keine empirische, sondern betrifft die Frage, welche Art von empirischen Belegen für den Entscheid relevant ist, ob ein Wesen derartige Einstellungen hat.Es wird die These aufgestellt, dass Sprachen ein notwendiger Begleitumstand einer jeglichen propositionalen Haltung ist. Der Gedanke ist zwar nicht neu, aber es finden sich wenige Argu‐mente zu seiner Stützung in der Literatur; eines wird hier ausgeführt.Entscheidend für die vorgelegten Betrachtungen ist die Auffassung, wonach Glaube vom Begriff der objektiven Wahrheit abhängt, und dieser kommt erst mit der Sprache. (shrink)

This paper explores an initially attractive principle connecting beliefs in general with beliefs about what beliefs are rational. The principle turns out to be violated by intuitively rational beliefs in some situations. The paper lays out some options for reacting to this fact.

Can it be rational to be religious? Robert Audi gives a persuasive positive answer through an account of rationality and a rich, nuanced understanding of what religious commitment means. It is not just a matter of belief, but of emotions and attitudes such as faith and hope, of one's outlook on the world, and of commitment to live in certain ways.

rationality has increasingly been a target of attack in contemporary educational research and practice and in its place practical reason and situated thinking have become a focus of interest. The argument here is that something is lost in this. In illustrating how we might think about the issue, this paper makes a response to the charge that as a result of his commitment to the ‘Enlightenment project’ Vygotsky holds abstract rationality as the pinnacle of thought. Against this it is argued (...) that Vygotsky had a far more sophisticated appreciation of reason and of its remit. The paper proceeds first by examining the picture of Vygotsky that is presented in the work of James Wertsch, and especially his claim that Vygotsky was an ambivalent rationalist, goes on to provide an account of Vygotsky that corrects this picture, and develops this in the light of the work of Robert Brandom, who shares Vygotsky’s inheritance of Hegel. The conclusion towards which this piece points is that the philosophical underpinnings of Vygotsky’s work provide a radically different idea of rationality and epistemology from that characterised as abstract rationality and that this has significance for education studies. (shrink)

This paper seeks to elucidate the distinctive nature of the rational impression on its own terms, asking precisely what it means for the Stoics to define logikē phantasia as an impression whose content is expressible in language. I argue first that impression, generically, is direct and reflexive awareness of the world, the way animals get information about their surroundings. Then, that the rational impression, specifically, is inherently conceptual, inferential, and linguistic, i.e. thick with propositional content, the way humans receive incoming (...) information from the world. When we suspend certain contemporary assumptions about propositional content, the textual evidence can be taken at face value to reveal why, for the Stoics, rational impressions are called thoughts (noēseis) and how the Stoics’ novel semantic entities called lekta (roughly, the meanings of our words) depend on rational impressions for their subsistence. (shrink)

In Minimal Rationality, Christopher Cherniak boldly challenges the myth of Man the the Rational Animal and the central role that the "perfectly rational...

Rationalization occurs when a person has performed an action and then concocts the beliefs and desires that would have made it rational. Then, people often adjust their own beliefs and desires to match the concocted ones. While many studies demonstrate rationalization, and a few theories describe its underlying cognitive mechanisms, we have little understanding of its function. Why is the mind designed to construct post hoc rationalizations of its behavior, and then to adopt them? This may accomplish an important task: (...) transferring information between the different kinds of processes and representations that influence our behavior. Human decision making does not rely on a single process; it is influenced by reason, habit, instinct, norms, and so on. Several of these influences are not organized according to rational choice. Rationalization extracts implicit information – true beliefs and useful desires – from the influence of these non-rational systems on behavior. This is a useful fiction – fiction, because it imputes reason to non-rational psychological processes; useful, because it can improve subsequent reasoning. More generally, rationalization belongs to the broader class of representational exchange mechanisms, which transfer information between many different kinds of psychological representations that guide our behavior. Representational exchange enables us to represent any information in the manner best suited to the particular tasks that require it, balancing accuracy, efficiency, and flexibility in thought. The theory of representational exchange reveals connections between rationalization and theory of mind, inverse reinforcement learning, thought experiments, and reflective equilibrium. (shrink)

Predictable polarization is everywhere: we can often predict how people’s opinions, including our own, will shift over time. Extant theories either neglect the fact that we can predict our own polarization, or explain it through irrational mechanisms. They needn’t. Empirical studies suggest that polarization is predictable when evidence is ambiguous, that is, when the rational response is not obvious. I show how Bayesians should model such ambiguity and then prove that—assuming rational updates are those which obey the value of evidence—ambiguity (...) is necessary and sufficient for the rationality of predictable polarization. The main theoretical result is that there can be a series of such updates, each of which is individually expected to make you more accurate, but which together will predictably polarize you. Polarization results from asymmetric increases in accuracy. This mechanism is not only theoretically possible, but empirically plausible. I argue that cognitive search—searching a cognitively accessible space for a particular item—often yields asymmetrically ambiguous evidence, I present an experiment supporting its polarizing effects, and I use simulations to show how it can explain two of the core causes of polarization: confirmation bias and the group polarization effect. (shrink)

It is widely held that Bayesian decision theory is the final word on how a rational person should make decisions. However, Leonard Savage--the inventor of Bayesian decision theory--argued that it would be ridiculous to use his theory outside the kind of small world in which it is always possible to "look before you leap." If taken seriously, this view makes Bayesian decision theory inappropriate for the large worlds of scientific discovery and macroeconomic enterprise. When is it correct to use Bayesian (...) decision theory--and when does it need to be modified? Using a minimum of mathematics, Rational Decisions clearly explains the foundations of Bayesian decision theory and shows why Savage restricted the theory's application to small worlds. The book is a wide-ranging exploration of standard theories of choice and belief under risk and uncertainty. Ken Binmore discusses the various philosophical attitudes related to the nature of probability and offers resolutions to paradoxes believed to hinder further progress. In arguing that the Bayesian approach to knowledge is inadequate in a large world, Binmore proposes an extension to Bayesian decision theory--allowing the idea of a mixed strategy in game theory to be expanded to a larger set of what Binmore refers to as "muddled" strategies. Written by one of the world's leading game theorists, Rational Decisions is the touchstone for anyone needing a concise, accessible, and expert view on Bayesian decision making. (shrink)

It is commonly thought that one is irrationally akratic when one believes one ought to F but does not intend to F. However, some philosophers, following Robert Audi, have argued that it is sometimes rational to have this combination of attitudes. I here consider the question of whether rational akrasia is possible. I argue that those arguments for the possibility of rational akrasia advanced by Audi and others do not succeed. Specifically, I argue that cases in which an akratic agent (...) acts as he has most reason to act, and cases in which an akratic agent achieves a kind of global coherence he wouldn’t have achieved had he instead formed intentions in line with his best judgment, do not establish the possibility of rational akrasia. However, I do think that rational akrasia is possible, and I present two arguments for this thesis. The first argument involves a case in which one is incapable of revising one’s belief about what one ought to do, where one also acknowledges this belief to be insufficiently supported by the evidence. The second argument involves a case in which one rationally believes that one ought to have an akratic combination of attitudes. (shrink)

Rational Sentimentalism develops a novel theory of the sentimental values. These values, which include the funny, the disgusting, and the shameful, are profoundly important because they set standards for emotional responses that are part of our shared human nature. Yet moral philosophers have neglected them relative to their prominence in human mental life. The theory is sentimentalist because it holds that these values are emotion-dependent—contrary to some prominent accounts of the funny and the disgusting. Its rational aspect arises from its (...) insistence that the shameful (e.g.) is not whatever elicits shame but what makes shame fitting. Shameful traits provide reasons to be ashamed that do not depend on whether one is disposed to be ashamed of them. Furthermore, these reasons to be ashamed issue in reasons to act as shame dictates: to conceal. Sentimentalism requires a compatible theory of emotion and emotional fittingness. The book explicates a motivational theory of emotion that explains the peculiarities of emotional motivation, as other theories cannot. It argues that a class of emotions are psychological kinds with the same goal across cultures, despite differences in their elicitors. It then develops an account of fittingness that helps to differentiate reasons of fit, which bear on the sentimental values, from other considerations for or against having an emotion. Some significant and controversial conclusions emerge from rational sentimentalism. The sentimental values conflict with one another, and with morality, but nevertheless provide practical reasons that apply to humans—though not to all rational agents. (shrink)

The study of rationality and practical reason, or rationality in action, has been central to Western intellectual culture. In this invigorating book, John Searle lays out six claims of what he calls the Classical Model of rationality and shows why they are false. He then presents an alternative theory of the role of rationality in thought and action. A central point of Searle's theory is that only irrational actions are directly caused by beliefs and desires—for example, the actions of a (...) person in the grip of an obsession or addiction. In most cases of rational action, there is a gap between the motivating desire and the actual decision making. The traditional name for this gap is "freedom of the will." According to Searle, all rational activity presupposes free will. For rationality is possible only where one has a choice among various rational as well as irrational options. Unlike many philosophical tracts, Rationality in Action invites the reader to apply the author's ideas to everyday life. Searle shows, for example, that contrary to the traditional philosophical view, weakness of will is very common. He also points out the absurdity of the claim that rational decision making always starts from a consistent set of desires. Rational decision making, he argues, is often about choosing between conflicting reasons for action. In fact, humans are distinguished by their ability to be rationally motivated by desire-independent reasons for action. Extending his theory of rationality to the self, Searle shows how rational deliberation presupposes an irreducible notion of the self. He also reveals the idea of free will to be essentially a thesis of how the brain works. (shrink)

Rationality requires that we intend the means that we believe are necessary for achieving our ends. Instrumental Rationality explores the formulation and status of this requirement of means-ends coherence. In particular, it is concerned with understanding what means-ends coherence requires of us as believers and agents, and why.

What should a person do when, through no fault of her own, she ends up believing a false moral theory? Some suggest that she should act against what the false theory recommends; others argue that she should follow her rationally held moral beliefs. While the former view better accords with intuitions about cases, the latter one seems to enjoy a critical advantage: It seems better able to render moral requirements ‘followable’ or ‘action-guiding.’ But this tempting thought proves difficult to justify. (...) Indeed, whether it can be justified turns out to depend importantly on the rational status of epistemic akrasia. Furthermore, it can be argued, from premises all parties to the moral ignorance debate should accept, that rational epistemic akrasia is possible. If the argument proves successful, it follows that a person should sometimes act against her rationally held moral convictions. (shrink)

This book discusses how rational choice theory grew out of RAND's work for the US Air Force. It concentrates on the work of William J. Riker, Kenneth J. Arrow, James M. Buchanan, Russel Hardin, and John Rawls. It argues that within the context of the US Cold War with its intensive anti-communist and anti-collectivist sentiment, the foundations of capitalist democracy were grounded in the hyper individualist theory of non-cooperative games.

It is widely held that Bayesian decision theory is the final word on how a rational person should make decisions. However, Leonard Savage--the inventor of Bayesian decision theory--argued that it would be ridiculous to use his theory outside the kind of small world in which it is always possible to "look before you leap." If taken seriously, this view makes Bayesian decision theory inappropriate for the large worlds of scientific discovery and macroeconomic enterprise. When is it correct to use Bayesian (...) decision theory--and when does it need to be modified? Using a minimum of mathematics, Rational Decisions clearly explains the foundations of Bayesian decision theory and shows why Savage restricted the theory's application to small worlds. The book is a wide-ranging exploration of standard theories of choice and belief under risk and uncertainty. Ken Binmore discusses the various philosophical attitudes related to the nature of probability and offers resolutions to paradoxes believed to hinder further progress. In arguing that the Bayesian approach to knowledge is inadequate in a large world, Binmore proposes an extension to Bayesian decision theory--allowing the idea of a mixed strategy in game theory to be expanded to a larger set of what Binmore refers to as "muddled" strategies. Written by one of the world's leading game theorists, Rational Decisions is the touchstone for anyone needing a concise, accessible, and expert view on Bayesian decision making. (shrink)

This article defends the Fixed Point Thesis: that it is always a rational mistake to have false beliefs about the requirements of rationality. The Fixed Point Thesis is inspired by logical omniscience requirements in formal epistemology. It argues to the Fixed Point Thesis from the Akratic Principle: that rationality forbids having an attitude while believing that attitude is rationally forbidden. It then draws out surprising consequences of the Fixed Point Thesis, for instance that certain kinds of a priori justification are (...) indefeasible and that misleading all-things-considered evidence about rational requirements is impossible. Finally, the Fixed Point Thesis is applied to defend the Right Reasons position on peer disagreement, according to which an agent who has drawn the correct conclusion from her evidence should retain belief in that conclusion even in the face of disagreeing peers. (shrink)

Personal autonomy is often lauded as a key value in contemporary Western bioethics. Though the claim that there is an important relationship between autonomy and rationality is often treated as uncontroversial in this sphere, there is also considerable disagreement about how we should cash out the relationship. In particular, it is unclear whether a rationalist view of autonomy can be compatible with legal judgments that enshrine a patient's right to refuse medical treatment, regardless of whether the reasons underpinning the choice (...) are known and rational, or indeed whether they even exist. Jonathan Pugh brings recent philosophical work on the nature of rationality to bear on the question of how we should understand personal autonomy in contemporary bioethics. In doing so, he develops a new framework for thinking about the concept of autonomy, one that is grounded in an understanding of the different roles that rational beliefs and rational desires have to play in it. Pugh's account allows for a deeper understanding of d the relationship between our freedom to act and our capacity to decide autonomously. His rationalist perspective is contrasted with other prominent accounts of autonomy in bioethics, and the revisionary implications it has for practical questions in biomedicine are also outlined. (shrink)

We ordinarily suppose that there is a difference between having and failing to exercise a rational capacity on the one hand, and lacking a rational capacity altogether on the other. This is crucial for our allocations of responsibility. Someone who has but fails to exercise a capacity is responsible for their failure to exercise their capacity, whereas someone who lacks a capacity altogether is not. However, as Gary Watson pointed out in his seminal essay ’Skepticism about Weakness of Will’, the (...) idea of an unexercised capacity is much more difficult to make sense of than it initially appears. The aim of ’Rational Capacities’ is to provide the needed explication of this idea. (shrink)

Some philosophers think that rationality consists in responding correctly to reasons, or alternatively in responding correctly to beliefs about reasons. This paper considers various possible interpretations of ‘responding correctly to reasons’ and of ‘responding correctly to beliefs about reasons’, and concludes that rationality consists in neither, under any interpretation. It recognizes that, under some interpretations, rationality does entail responding correctly to beliefs about reasons. That is: necessarily, if you are rational you respond correctly to your beliefs about reasons.

In her book Extended Rationality: A Hinge Epistemology (2015), Annalisa Coliva puts forward an anti-sceptical proposal based on the idea that the notion of rationality extends to the unwarrantable presuppositions “that make the acquisition of perceptual warrants possible” (2015: 150). These presuppositions are commonly the target of sceptical arguments, and by showing that they are on the one hand unwarrantable, but on the other are constitutive components of rationality itself, she reveals that they are beyond rational doubt and thus avoids (...) scepticism. Part of Coliva’s defence of using extended rationality in this way involves distancing it from relativist interpretations, which she describes as “devastating” (2015: 120). She proposes two ways that someone might attempt to formulate epistemic relativism from her extended rationality view, and argues that both would be unsuccessful because they require describing alternative conceptions of rationality which are “unintelligible” (in the first case), or “inconceivable” (in the second). The superficial claim of this chapter is that Coliva’s arguments, as they stand, are insufficient to dismiss relativism. She fails to show that the conception of rationality needed for the first formulation of relativism is unintelligible, and overestimates the significance of the second formulation’s conception turning out to be inconceivable. But I also highlight a deeper problem: neither formulation follows a realistic blueprint for relativism, and so these were the wrong possibilities to consider in the first place. To address this issue, I propose a third, more plausible, way in which someone might attempt to formulate relativism on the basis of Coliva’s account. I leave open whether this strategy is successful, or whether a version of Coliva’s criticisms apply to it too. (shrink)

Rationalization in the sense of biased self-justification is very familiar. It's not cheating because everyone else is doing it too. I didn't report the abuse because it wasn't my place. I understated my income this year because I paid too much in tax last year. I'm only a social smoker, so I won't get cancer. The mental mechanisms subserving rationalization have been studied closely by psychologists. However, when viewed against the backdrop of philosophical accounts of the regulative role of truth (...) in doxastic deliberation , rationalization can look very puzzling. Almost all contemporary philosophers endorse a version of the thesis of deliberative exclusivity—a thinker cannot in full consciousness decide whether to believe that p in a way that issues directly in forming a belief by adducing anything other than considerations that he or she regards as relevant to the truth of p. But, as I argue, rationalization involves the weighing of considerations that the thinker kn.. (shrink)

Do people tend to be overconfident? Many think so. They’ve run studies on whether people are calibrated: whether their average confidence in their opinions matches the proportion of those opinions that are true. Under certain conditions, people are systematically ‘over-calibrated’—for example, of the opinions they’re 80% confident in, only 60% are true. From this empirical over-calibration, it’s inferred that people are irrationally overconfident. My question: When and why is this inference warranted? Answering it requires articulating a general connection between being (...) rational and being right—something extant studies have not done. I show how to do so using the notion of deference. This provides a theoretical foundation for calibration research, but also reveals a flaw: the connection between being rational and being right is much weaker than is standardly assumed, since rational people can often be expected to be miscalibrated. Thus we can’t test whether people are overconfident by simply testing whether they are over-calibrated; instead, we must try to predict the rational deviations from calibration, and then compare those predictions to people’s performance. I show how this can be done—and that doing so complicates the interpretation of robust empirical effects. (shrink)

The approximate number system (ANS) enables organisms to represent the approximate number of items in an observed collection, quickly and independently of natural language. Recently, it has been proposed that the ANS goes beyond representing natural numbers by extracting and representing rational numbers (Clarke & Beck, 2021a). Prior work demonstrates that adults and children discriminate ratios in an approximate and ratio-dependent manner, consistent with the hallmarks of the ANS. Here, we use a well-known “connectedness illusion” to provide evidence that these (...) ratio-dependent ratio discriminations are (a) based on the perceived number of items in seen displays (and not just non-numerical confounds), (b) are not dependent on verbal working memory, or explicit counting routines, and (c) involve representations with a part-whole (or subset-superset) format, like a fraction, rather than a part-part format, like a ratio. These results vindicate key predictions of the hypothesis that the ANS represents rational numbers. (shrink)

This paper is about the connection between rationality and accuracy. I show that one natural picture about how rationality and accuracy are connected emerges if we assume that rational agents are rationally omniscient. I then develop an alternative picture that allows us to relax this assumption, in order to accommodate certain views about higher order evidence.