In this paper I look at belief and degrees of belief through the lens of inquiry. I argue that belief and degrees of belief play different roles in inquiry. In particular I argue that belief is a “settling” attitude in a way that degrees of belief are not. Along the way I say more about what inquiring amounts to, argue for a central norm of inquiry connecting inquiry and belief and say more about just what it means to have an (...) inquiry or question settled. (shrink)

This article gives an overview of some recent debates about the relationship between reasons and rational requirements of coherence - e.g. the requirements to be consistent in our beliefs and intentions, and to intend what we take to be the necessary means to our ends.

In this chapter, we critically examine the most important extant ways of understanding and motivating the idea that reasons for belief are normative. First, we examine the proposal that the distinction between explanatory and so-called normative reasons that is commonly drawn in moral philosophy can be rather straightforwardly applied to reasons for belief, and that reasons for belief are essentially normative precisely when they are normative reasons. In the course of this investigation, we explore the very nature of the reasons-for-belief (...) relation, as well as the ontology of such reasons. Second, we examine the idea that the normativity derives from the internal connection between reasons for belief and epistemic justification, distinguishing between two distinct normativist accounts of justification, a weaker and a stronger one. We argue that neither line of argument is compelling. Pending further arguments, we conclude that normativism about reasons for belief is not supported. (shrink)

Thomas Kroedel argues that the lottery paradox can be solved by identifying epistemic justification with epistemic permissibility rather than epistemic obligation. According to his permissibility solution, we are permitted to believe of each lottery ticket that it will lose, but since permissions do not agglomerate, it does not follow that we are permitted to have all of these beliefs together, and therefore it also does not follow that we are permitted to believe that all tickets will lose. I present two (...) objections to this solution. First, even if justification itself amounts to no more than epistemic permissibility, the lottery paradox recurs at the level of doxastic obligations unless one adopts an extremely permissive view about suspension of belief that is in tension with our practice of doxastic criticism. Second, even if there are no obligations to believe lottery propositions, the permissibility solution fails because epistemic permissions typically agglomerate, and the lottery case provides no exception to this rule. (shrink)

Kiesewetter defends the normativity of rationality by presenting a new solution to the problems that arise from the common assumption that we ought to be rational. He provides a defence of a reason-response conception of rationality, an evidence-relative account of reason, and an explanation of structural irrationality in relation to these accounts.

Some writers object to logical pluralism on the grounds that logic is normative. The rough idea is that the relation of logical consequence has consequences for what we ought to think and h...

The paper tries to spell out a connection between deductive logic and rationality, against Harman's arguments that there is no such connection, and also against the thought that any such connection would preclude rational change in logic. One might not need to connect logic to rationality if one could view logic as the science of what preserves truth by a certain kind of necessity (or by necessity plus logical form); but the paper points out a serious obstacle to any such (...) view. (shrink)

Many philosophers hold that if an agent acts intentionally, she must know what she is doing. Although the scholarly consensus for many years was to reject the thesis in light of presumed counterexamples by Donald Davidson, several scholars have recently argued that attention to aspectual distinctions and the practical nature of this knowledge shows that these counterexamples fail. In this paper I defend a new objection against the thesis, one modelled after Timothy Williamson’s anti-luminosity argument. Since this argument relies on (...) general principles about the nature of knowledge rather than on intuitions about fringe cases, the recent responses that have been given to defuse the force of Davidson’s objection are silent against it. Moreover, the argument suggests that even weaker theses connecting practical entities with knowledge are also false. Recent defenders of the thesis that there is a necessary connection between knowledge and intentional action are motivated by the insight that this connection is non-accidental. I close with a positive proposal to account for the non-accidentality of this link without appeal to necessary connections by drawing an extended analogy between practical and perceptual knowledge. (shrink)

This paper elaborates a new solution to the lottery paradox, according to which the paradox arises only when we lump together two distinct states of being confident that p under one general label of ‘belief that p’. The two-state conjecture is defended on the basis of some recent work on gradable adjectives. The conjecture is supported by independent considerations from the impossibility of constructing the lottery paradox both for risk-tolerating states such as being afraid, hoping or hypothesizing, and for risk-averse, (...) certainty-like states. The new proposal is compared to views within the increasingly popular debate opposing dualists to reductionists with respect to the relation between belief and degrees of belief. (shrink)

Logic in Buddhist Philosophy concerns the systematic study of anumāna (often translated as inference) as developed by Dignāga (480-540 c.e.) and Dharmakīti (600-660 c.e.). Buddhist logicians think of inference as an instrument of knowledge (pramāṇa) and, thus, logic is considered to constitute part of epistemology in the Buddhist tradition. According to the prevalent 20th and early 21st century ‘Western’ conception of logic, however, logical study is the formal study of arguments. If we understand the nature of logic to be formal, (...) it is difficult to see what bearing logic has on knowledge. In this paper, by weaving together the main threads of thought that are salient in Dignāga’s and Dharmakīti’s texts, I shall re-conceive the nature of logic in the context of epistemology and demarcate the logical part of epistemology which can be recognised as logic. I shall demonstrate that we can recognise the logical significance of inference as understood by Buddhist logicians despite the fact that its logical significance lies within the context of knowledge. (shrink)

Philosophers of action of different persuasions have suggested that there is a tight connection between the phenomenon of intending and the phenomena of “being settled on” and of “settling” a course of action. For many, this connection supports an important constraint on intention: one may only intend what one takes one’s so intending as settling. Traditionally, this has been understood as a doxastic constraint on intention: what one takes one’s intention as settling is what one believes one’s so intending as (...) settling. This paper proposes an alternative conception of such a constraint. The idea is to conceive of it in terms of the attitude of reliance, rather than of belief. The aim of the paper is three-fold: to clarify the connection between intending to act and the phenomena of being settled on and of settling a course of action, to provide support for the reliance conception of the cited constraint, and to show that this conception drives a wedge in the familiar dispute, between doxastic and conative accounts of intention, as to whether intending to act necessarily involves the belief that one will so act. (shrink)

According to the error theory, normative judgments are beliefs that ascribe normative properties, but these properties do not exist. I have argued elsewhere (in "Can We Believe the Error Theory?") that we cannot believe this theory. Several philosophers have replied to this argument. In this chapter, I respond to their replies.

White, Christensen, and Feldman have recently endorsed uniqueness, the thesis that given the same total evidence, two rational subjects cannot hold different views. Kelly, Schoenfield, and Meacham argue that White and others have at best only supported the weaker, merely intrapersonal view that, given the total evidence, there are no two views which a single rational agent could take. Here, we give a new argument for uniqueness, an argument with deliberate focus on the interpersonal element of the thesis. Our argument (...) is that the best explanation of the value of promoting rationality is an explanation that entails uniqueness. (shrink)

The representation theorems of expected utility theory show that having certain types of preferences is both necessary and sufficient for being representable as having subjective probabilities. However, unless the expected utility framework is simply assumed, such preferences are also consistent with being representable as having degrees of belief that do not obey the laws of probability. This fact shows that being representable as having subjective probabilities is not necessarily the same as having subjective probabilities. Probabilism can be defended on the (...) basis of the representation theorems only if attributions of degrees of belief are understood either antirealistically or purely qualitatively, or if the representation theorems are supplemented by arguments based on other considerations (simplicity, consilience, and so on) that single out the representation of a person as having subjective probabilities as the only true representation of the mental state of any person whose preferences conform to the axioms of expected utility theory. (shrink)

I consider the metaphysical consequences of the view that propositional attitudes have essential normative properties. I argue that realism should take a weak rather than a strong form. I argue that expressivism cannot get off the ground. And I argue that eliminativism is self-refuting.

For many epistemologists, and for many philosophers more broadly, it is axiomatic that rationality requires you to take the doxastic attitudes that your evidence supports. Yet there is also another current in our talk about rationality. On this usage, rationality is a matter of the right kind of coherence between one's mental attitudes. Surprisingly little work in epistemology is explicitly devoted to answering the question of how these two currents of talk are related. But many implicitly assume that evidence -responsiveness (...) guarantees coherence, so that the rational impermissibility of incoherence will just fall out of the putative requirement to take the attitudes that one's evidence supports, and so that coherence requirements do not need to be theorized in their own right, apart from evidential reasons. In this paper, I argue that this is a mistake, since coherence and evidence -responsiveness can in fact come into conflict. More specifically, I argue that in cases of misleading higher-order evidence, there can be a conflict between believing what one's evidence supports and satisfying a requirement that I call “inter-level coherence ”. This illustrates why coherence requirements and evidential reasons must be separated and theorized separately. (shrink)

Philosophical arguments usually are and nearly always should be abductive. Across many areas, philosophers are starting to recognize that often the best we can do in theorizing some phenomena is put forward our best overall account of it, warts and all. This is especially true in esoteric areas like logic, aesthetics, mathematics, and morality where the data to be explained is often based in our stubborn intuitions. -/- While this methodological shift is welcome, it's not without problems. Abductive arguments involve (...) significant theoretical resources which themselves can be part of what's being disputed. This means that we will sometimes find otherwise good arguments which suggest their own grounds are problematic. In particular, sometimes revising our beliefs on the basis of such an argument can undermine the very justification we used in that argument. -/- This feature, which I'll call self-effacingness, occurs most dramatically in arguments against our standing views on the esoteric subject matters mentioned above: logic, mathematics, aesthetics, and morality. This is because these subject matters all play a role in how we reason abductively. This isn't an idle fact; we can resist some challenges to our standing beliefs about these subject matters exactly because the challenges are self-effacing. The self-effacing character of certain arguments is thus both a benefit and limitation of the abductive turn and deserves serious attention. I aim to give it the attention it deserves. (shrink)

A natural suggestion and increasingly popular account of how to revise our logical beliefs treats revision of logic analogously to the revision of scientific theories. I investigate this approach and argue that simple applications of abductive methodology to logic result in revision-cycles, developing a detailed case study of an actual dispute with this property. This is problematic if we take abductive methodology to provide justification for revising our logical framework. I then generalize the case study, pointing to similarities with more (...) recent and popular heterodox logics such as naïve logics of truth. I use this discussion to motivate a constraint—logical partisanhood—on the uses of such methodology: roughly: both the proposed alternative and our actual background logic must be able to agree that moving to the alternative logic is no worse than staying put. (shrink)

I distinguish two ways of developing anti-exceptionalist approaches to logical revision. The first emphasizes comparing the theoretical virtuousness of developed bodies of logical theories, such as classical and intuitionistic logic. I'll call this whole theory comparison. The second attempts local repairs to problematic bits of our logical theories, such as dropping excluded middle to deal with intuitions about vagueness. I'll call this the piecemeal approach. I then briefly discuss a problem I've developed elsewhere for comparisons of logical theories. Essentially, the (...) problem is that a pair of logics may each evaluate the alternative as superior to themselves, resulting in oscillation between logical options. The piecemeal approach offers a way out of this problem andthereby might seem a preferable to whole theory comparisons. I go on to show that reflective equilibrium, the best known piecemeal method, has deep problems of its own when applied to logic. (shrink)

I discuss Greg Restall’s attempt to generate an account of logical consequence from the incoherence of certain packages of assertions and denials. I take up his justification of the cut rule and argue that, in order to avoid counterexamples to cut, he needs, at least, to introduce a notion of logical form. I then suggest a few problems that will arise for his account if a notion of logical form is assumed. I close by sketching what I take to be (...) the most natural minimal way of distinguishing content and form and suggest further problems arising for this route. (shrink)

Epistemic subjectivism, as I am using the term, is a view in the same spirit as relativism, rooted in skepticism about the objectivity or universality of epistemic norms. I explore some ways that we might motivate subjectivism drawing from some common themes in analytic epistemology. Without diagnosing where the arguments go wrong, I argue that the resulting position is untenable.

Epistemic naturalism holds that the results or methodologies from the cognitive sciences are relevant to epistemology, and some have maintained that scientific methods are more compatible with externalist theories of justification than with internalist theories. But practically all discussions about naturalized epistemology are framed exclusively in terms of cognitive psychology, which is only one of the cognitive sciences. The question addressed in this essay is whether a commitment to naturalism really does favor externalism over internalism, and we offer reasons for (...) thinking that naturalism in epistemology is compatible with both internalist and externalist conceptions of justification. We also argue that there are some distinctively internalist aims that are currently being studied scientifically and these notions, and others, should be studied by scientific methods. (shrink)

Many writers have held that in his later work, David Lewis adopted a theory of predicate meaning such that the meaning of a predicate is the most natural property that is (mostly) consistent with the way the predicate is used. That orthodox interpretation is shared by both supporters and critics of Lewis's theory of meaning, but it has recently been strongly criticised by Wolfgang Schwarz. In this paper, I accept many of Schwarze's criticisms of the orthodox interpretation, and add some (...) more. But I also argue that the orthodox interpretation has a grain of truth in it, and seeing that helps us appreciate the strength of Lewis's late theory of meaning. (shrink)

I argue that what evidence an agent has does not supervene on how she currently is. Agents do not always have to infer what the past was like from how things currently seem; sometimes the facts about the past are retained pieces of evidence that can be the start of reasoning. The main argument is a variant on Frank Arntzenius’s Shangri La example, an example that is often used to motivate the thought that evidence does supervene on current features.

A contribution to a symposium on Herman Cappelen's Philosophy without Intuitions.

I consider the problem of how to derive what an agent believes from their credence function and utility function. I argue the best solution of this problem is pragmatic, i.e. it is sensitive to the kinds of choices actually facing the agent. I further argue that this explains why our notion of justified belief appears to be pragmatic, as is argued e.g. by Fantl and McGrath. The notion of epistemic justification is not really a pragmatic notion, but it is being (...) applied to a pragmatically defined concept, i.e. belief. (shrink)

Evidentialism is the thesis that all reasons to believe p are evidence for p. Pragmatists hold that pragmatic considerations – incentives for believing – can also be reasons to believe. Nishi Shah, Thomas Kelly and others have argued for evidentialism on the grounds that incentives for belief fail a ‘reasoning constraint’ on reasons: roughly, reasons must be considerations we can reason from, but we cannot reason from incentives to belief. In the first half of the paper, I show that this (...) argument fails: the claim that we cannot reason from incentives is either false or does not combine with the reasoning constraint to support evidentialism. However, the failure of this argument suggests an alternative route to evidentialism. Roughly, reasons must be premises of good reasoning, but it is not good reasoning to reason from incentives to belief. The second half of the paper develops and defends this argument for evidentialism. (shrink)

In this article I am going to reconstruct Stephen Toulmin’s procedural theory of concepts and explanations in order to develop two overlooked ideas from his philosophy of science: methods of representations and inferential techniques. I argue that these notions, when properly articulated, could be useful for shedding some light on how scientific reasoning is related to representational structures, concepts, and explanation within scientific practices. I will explore and illustrate these ideas by studying the development of the notion of instantaneous speed (...) during the passage from Galileo’s geometrical physics to analytical mechanics. At the end, I will argue that methods of representations could be considered as constitutive of scientific inference; and I will show how these notions could connect with other similar ideas from contemporary philosophy of science like those of models and model-based reasoning. (shrink)

The philosophical literature on reasoning is dominated by the assumption that reasoning is essentially a matter of following rules. This paper challenges this view, by arguing that it misrepresents the nature of reasoning as a personal level activity. Reasoning must reflect the reasoner’s take on her evidence. The rule-following model seems ill-suited to accommodate this fact. Accordingly, this paper suggests replacing the rule-following model with a different, semantic approach to reasoning.

Even if you believe just what you rationally ought to believe, you may be open to rational criticism if you do so ‘for the wrong reasons’, as we say. Some have thought that this familiar observation supports the idea that there are diachronic norms of epistemic rationality – namely, norms of good reasoning. Partly drawing upon Carroll's story of Achilles and the Tortoise, this article criticises this line of thought on the grounds that it rests on a mistaken conception of (...) inference. (shrink)

What exactly is reasoning? While debate on this question is ongoing, most philosophers seem to agree on at least the following: reasoning is a mental process operating on contents, which consists in adopting or revising some of your attitudes in light of others. In this paper, I argue that this characterisation is mistaken: there is no single mental phenomenon that satisfies both of these conditions. Instead, I characterise two distinct mental phenomena, which I call ‘deducing’, on the one hand, and (...) ‘reasoning’ or ‘inference’ on the other, to play each of these roles. Recognising this division of labour is essential to developing a better understanding of our rational economy. (shrink)

Epistemic reasons are mental states. They are not propositions or non-mental facts. The discussion proceeds as follows. Section 1 introduces the topic. Section 2 gives two concrete examples of how our topic directly affects the internalism/externalism debate in normative epistemology. Section 3 responds to an argument against the view that reasons are mental states. Section 4 presents two problems for the view that reasons are propositions. Section 5 presents two problems for the view that reasons are non-mental facts. Section 6 (...) argues that reasons are mental states. Section 7 responds to objections. (shrink)

Perceptual dogmatism holds that if it perceptually seems to S that P, then S thereby has prima facie perceptual justification for P. But suppose Wishful Willy's desire for gold cognitively penetrates his perceptual experience and makes it seem to him that the yellow object is a gold nugget. Intuitively, his desire-penetrated seeming can't provide him with prima facie justification for thinking that the object is gold. If this intuitive response is correct, dogmatists have a problem. But if dogmatists have a (...) problem, you do too (well, most of you anyway). Reliabilists have denounced dogmatism's cognitive penetration problems, but they have problems with cognitive penetration that are even worse. (shrink)

It has recently been argued that a non-Bayesian probabilistic version of inference to the best explanation (IBE*) has a number of advantages over Bayesian conditionalization (Douven [2013]; Douven and Wenmackers [2017]). We investigate how IBE* could be generalized to uncertain evidential situations and formulate a novel updating rule IBE**. We then inspect how it performs in comparison to its Bayesian counterpart, Jeffrey conditionalization (JC), in a number of simulations where two agents, each updating by IBE** and JC, respectively, try to (...) detect the bias of a coin while they are only partially certain what side the coin landed on. We show that IBE** more often prescribes high probability to the actual bias than JC. We also show that this happens considerably faster, that IBE** passes higher thresholds for high probability, and that it in general leads to more accurate probability distributions than JC. (shrink)

Recent objections to epistemic permissivism have a metaepistemic flavor. Impermissivists argue that their view best accounts for connections between rationality, planning and deference. Impermissivism is also taken to best explain the value of rational belief and normative assessment. These objections pose a series of metaepistemic explanatory challenges for permissivism. In this paper, I illustrate how permissivists might meet their explanatory burdens by developing two permissivist metaepistemic views which fare well against the explanatory challenges.

This paper makes the non-monotonicity of a wide range of moral reasoning the basis of a case for particularism. Non-monotonicity threatens practical decision with an overwhelming informational complexity to which a form of ethical generalism seems the best response. It is argued that this impression is wholly misleading: the fact of non-monotonicity is best accommodated by the defence of four related theses in any theory of justification. First, the explanation of and defence of a default/challenge model of justification. Secondly, the (...) development of a theory of epistemic status and an explanation of those unearned entitlements that accrue to such status. Thirdly, an explanation of the basis of epistemic virtues. Finally, an account must be given of the executive capacity of rational decision itself as a ‘contentless ability’. This overall set of views can accommodate a limited role for generalizations about categories of evidence, but not such as to rescue a principled generalism. In particular, the version of particularism defended here explains why one ought not to accept the principled holism that has proved to be a problem for Dancy’s form of particularism. Ethics certainly involves hedged principles. However, principles cannot be self-hedging: there cannot be a that’s it operator in a principle as Richard Holton has claimed that there can be. Practical reasoning is concluded by the categorical detachment of the action-as-conclusion itself. (shrink)

This article discusses the philosophical relevance of recent computational work on inductive inference being conducted in the rapidly growing branch of artificial intelligence called machine learning.

ABSTRACTShould conciliating with disagreeing peers be considered sufficient for reaching rational beliefs? Thomas Kelly argues that when taken this way, Conciliationism lets those who enter into a disagreement with an irrational belief reach a rational belief all too easily. Three kinds of responses defending Conciliationism are found in the literature. One response has it that conciliation is required only of agents who have a rational belief as they enter into a disagreement. This response yields a requirement that no one should (...) follow. If the need to conciliate applies only to already rational agents, then an agent must conciliate only when her peer is the one irrational. A second response views conciliation as merely necessary for having a rational belief. This alone does little to address the central question of what is rational to believe when facing a disagreeing peer. Attempts to develop the response either reduce to the first response, or deem necessary an unnecessary doxastic revision, or imply that rational dilemmas obtain in cases where intuitively there are none. A third response tells us to weigh what our pre-disagreement evidence supports against the evidence from the disagreement itself. This invites epistemic akrasia. (shrink)

The paper is an opinionated tour of the literature on the reasons for which we hold beliefs and other doxastic attitudes, which I call ‘operative epistemic reasons’. After drawing some distinctions in §1, I begin in §2 by discussing the ontology of operative epistemic reasons, assessing arguments for and against the view that they are mental states. I recommend a pluralist non-mentalist view that takes seriously the variety of operative epistemic reasons ascriptions and allows these reasons to be both propositions (...) and truth-making facts. In §3, I turn to consider what it takes for a consideration to be an operative epistemic reason, examining three conditions – the representational, treating, and explanatory conditions – that have been proposed. I offer a novel view about the explanatory condition. In §4, I discuss the special case of inferential operative reasons and examine attempts to understand them in terms of rule-following, sketching a competence-based spinoff of dispositionalism. Finally, in §5, I consider whether there are non-inferential operative reasons, observing that one needn't countenance them to be a foundationalist but then developing a view about what they are and how they do and don't differ from inferential reasons. (shrink)

Jonas Olson writes that "a plausible moral error theory must be an error theory about all irreducible normativity". I agree. But unlike Olson, I think we cannot believe this error theory. I first argue that Olson should say that reasons for belief are irreducibly normative. I then argue that if reasons for belief are irreducibly normative, we cannot believe an error theory about all irreducible normativity. I then explain why I think Olson's objections to this argument fail. I end by (...) showing that Olson cannot defend his view as a partly revisionary alternative to an error theory about all irreducible normativity. (shrink)

What is the relation between entailment and reasons for belief? In this paper, I discuss several answers to this question, and I argue that these answers all face problems. I then propose the following answer: for all propositions p1,...,pn and q, if the conjunction of p1,..., and pn entails q, then there is a reason against a person's both believing that p1,..., and that pn and believing the negation of q. I argue that this answer avoids the problems that the (...) other answers to this question face, and that it does not face any other problems either. I end by showing what the relation between deductive logic, reasons for belief and reasoning is if this answer is correct. (shrink)

Marianna Bergamaschi Ganapini argues that we can believe the error theory. In this reply, I explain why I still think we cannot.

It is sometimes suggested that there are two kinds of reasoning: inferential reasoning and non-inferential reasoning. However, it is not entirely clear what the difference between these two kinds of reasoning is. In this paper, I try to answer the question what this difference is. I first discuss three answers to this question that I argue are unsatisfactory. I then give a different answer to this question, and I argue that this answer is satisfactory. I end by showing that this (...) answer can help to resolve some disagreements in which the difference between inferential and noninferential reasoning plays a role. (shrink)

The debate over physicalism in philosophy of mind can be seen as concerning an inconsistent tetrad of theses: (1) if physicalism is true, a priori physicalism is true; (2) a priori physicalism is false; (3) if physicalism is false, epiphenomenalism is true; (4) epiphenomenalism is false. This paper argues that one may resolve the debate by distinguishing two conceptions of the physical: on the theory‐based conception, it is plausible that (2) is true and (3) is false; on the object‐based conception, (...) it is plausible that (3) is true and (2) is false. the paper also defends and explores the version of physicalism that results from this strategy. (shrink)

According to externalist reliabilism and dogmatic foundationalism, it's possible to gain knowledge through a perceptual experience without being in a position to know that the experience is reliable. As a result, both of these views face the problem of making knowledge of perceptual reliability too easy, for they permit deducing perceptual reliability from particular perceptual experience without already knowing that these experiences are trustworthy. Ernest Sosa advocates a two-stage solution to the problem. At the first stage, a rich body of (...) perceptual animal knowledge is acquired. At the second stage, perceptual knowledge becomes reflective after deducing perceptual reliability from the initial body of perceptual animal knowledge. I defend the alternative approach of rejecting both externalist reliabilism and dogmatic foundationalism. According to the alternative view, perceptual knowledge and knowledge of perceptual reliability require each other. Such a cognitive structure seems viciously circular. I propose that the appearance of vicious circularity dissipates when the relationship in question is viewed, not as one of temporal priority, but instead as synchronic mutual dependence. At a given time, one cannot have perceptual knowledge without knowledge of perceptual reliability, and vice versa. Such mutual dependence, I argue, is benign. (shrink)

Ideal agents are role models whose perfection in some normative domain we try to approximate. But which form should this striving take? It is well known that following ideal rules of practical reasoning can have disastrous results for non-ideal agents. Yet, this issue has not been explored with respect to rules of theoretical reasoning. I show how we can extend Bayesian models of ideally rational agents in order to pose and answer the question of whether non-ideal agents should form new (...) degrees of belief in the same way as their ideal counterparts. I demonstrate that the epistemic and the practical case are parallel: following ideal rules does not always lead to optimal outcomes for non-ideal agents. (shrink)