Being More Realistic About Reasons: On Rationality and Reasons Perspectivism

This paper looks at whether it is possible to unify the requirements of rationality with the demands of normative reasons. It might seem impossible to do because one depends upon the agent's perspective and the other upon features of the situation. Enter Reasons Perspectivism. Reasons perspectivists think they can show that rationality does consist in responding correctly to reasons by placing epistemic constraints on these reasons. They think that if normative reasons are subject to the right epistemic constraints, rational requirements will correspond to the demands generated by normative reasons. While this proposal is prima facie plausible, it cannot ultimately unify reasons and rationality. There is no epistemic constraint that can do what reasons perspectivists would need it to do. Some constraints are too strict. The rest are too slack. This points to a general problem with the reasons‐first program. Once we recognize that the agent's epistemic position helps determine what she should do, we have to reject the idea that the features of the agent's situation can help determine what we should do. Either rationality crowds out reasons and their demands or the reasons will make unreasonable demands.     

Epistemic Rationality

Many epistemologists and philosophers of science, especially those with “naturalist” inclinations, argue that if there is to be any such thing as normativity or rationality in these domains, it must be instrumental—roughly, a matter of goal satisfaction—rather than something involving normative “oughts” that are independent of the satisfaction of our epistemic, cognitive, or other ends. This paper argues that while such an instrumental conception of epistemic rationality is perfectly respectable, even insofar as it concerns specifically epistemic ends, it cannot be the whole story about such normativity. Rather, it must be accompanied by a “categorical,” goal‐independent sort of normativity that cannot be reduced to instrumental rationality, both because instrumental rationality itself depends on a noninstrumental relationship between a belief/claim/theory and the evidence that renders it rational, and because the epistemic rationality of many beliefs is independent of the goals of their believers.     

Visions of rationality

The classical view that equates rationality with adherence to the laws of probability theory and logic has driven much research on inference. Recently, an increasing number of researchers have begun to espouse a view of rationality that takes account of organisms' adaptive goals, natural environments, and cognitive constraints. We argue that inference is carried out using boundedly rational heuristics, that is, heuristics that allow organisms to reach their goals under conditions of limited time, information, and computational capacity. These heuristics are ecologically rational in that they exploit aspects of both the physical and social environment in order to make adaptive inferences. We review recent work exploring this multifaceted conception of rationality.     

A diachronic perspective on peer disagreement in veritistic social epistemology

The main issue in the epistemology of peer disagreement is whether known disagreement among those who are in symmetrical epistemic positions undermines the rationality of their maintaining their respective views. Douven and Kelp have argued convincingly that this problem is best understood as being about how to respond to peer disagreement repeatedly over time, and that this diachronic issue can be best approached through computer simulation. However, Douven and Kelp’s favored simulation framework cannot naturally handle Christensen’s famous Mental Math example. As a remedy, I introduce an alternative (Bayesian) simulation framework, Laputa, inspired by Alvin Goldman’s seminal work on veritistic social epistemology. I show that Christensen’s conciliatory response, reasonably reconstructed and supplemented, gives rise to an increase in epistemic (veritistic) value only if the peers continue to recheck their mental math; else the peers might as well be steadfast. On a meta-level, the study illustrates the power of Goldman’s approach when combined with simulation techniques for handling the computational issues involved.

     

Belief and contextual acceptance

I develop a strategy for representing epistemic states and epistemic changes that seeks to be sensitive to the difference between voluntary and involuntary aspects of our epistemic life, as well as to the role of pragmatic factors in epistemology. The model relies on a particular understanding of the distinction between full belief and acceptance, which makes room for the idea that our reasoning on both practical and theoretical matters typically proceeds in a contextual way. Within this framework, I discuss how agents can rationally shift their credal probability functions so as to consciously modify some of their contextual acceptances; the present account also allows us to represent how the very set of contexts evolves. Voluntary credal shifts, in turn, might provoke changes in the agent’s beliefs, but I show that this is actually a side effect of performing multiple adjustments in the total lot of the agent’s acceptance sets. In this way we obtain a model that preserves many pre-theoretical intuitions about what counts as adequate rationality constraints on our actual practices—and hence about what counts as an adequate, normative epistemological perspective.     

Epistemology Culturalized

The anti-metaphysical intentions of naturalism can be respected without abandoning the project of a normative epistemology. The central assumptions of naturalism imply that (1.) the distinction between action and behaviour is spurious, and (2.) epistemology cannot continue to be a normative project. Difficulties with the second implication have been adressed by Normative Naturalism, but without violating the naturalistic consensus, it can only appreciate means-end-rationality. However, this does not suffice to justify its own implicit normative pretensions. According to our diagnosis, naturalism succumbs to the lure of an absolute observer's stance and thereby neglects the need for participation in communal practice. By contrast, methodical culturalism ties down the concepts of epistemology to the success of such practice. Only from this perspective, the normative force of epistemology can be appreciated. Also, the mind-body problem loosens its hold and the distinction between action and behaviour is reestablished. In the last section, the mutual relation between philosophy andscience is reconsidered. This revised version was published online in August 2006 with corrections to the Cover Date.     

Is believing for a normative reason a composite condition?

Here is a surprisingly neglected question in contemporary epistemology: what is it for an agent to believe that p in response to a normative reason for them to believe that p? On one style of answer, believing for the normative reason that q factors into believing that p in the light of the apparent reason that q, where one can be in that kind of state even if q is false, in conjunction with further independent conditions such as q’s being a normative reason to believe that p. The primary objective of this paper is to demonstrate that that style of answer cannot be right, because we must conceive of believing for a normative reason as constitutively involving a kind of rationality-involving relation that can be instantiated at all only if there is a known fact on the scene, which the agent treats as a normative reason. A secondary objective, achieved along the way, is to demonstrate that in their Prime Time (for the Basing Relation) Errol Lord and Kurt Sylvan do not succeed in undermining the factoring picture in general, only a simple-minded version of it.

     

有限理性的“占优启发式”和“齐当别”决策模型的作为 ——当Allais悖论杠杆撬动了期望效用理论

人们在做决策时常常要受到时间或知识的限制,有时还要受到其双重限制。关于人们是如何进行风险决策,早期有期望效用理论对其加以解释,但Allais悖论对其标准化地位提出了挑战。Simon的“有限理性”观点提出后,一些研究者开始致力于开发决策的“有限理性”模型。文章讨论并比较了无限理性的期望效用理论被Allais悖论杠杆撬动之后,有限理性的“占优启发式”和“齐当别”决策模型所能做的和所不能做的。两种模型的决策标准、计算策略以及未来研究的展望也一并作了讨论     

The Difference Between Moral and Rational “Oughts”: An Expressivist Account

Morality and rationality are both normative: the moral claim “you ought to help others” is a genuine normative judgment, as well as the rational maxim “you ought to brush your teeth twice a day”. But it seems that there is a crucial difference these two judgments. In the first part of this paper, I argue that this difference is to be understood as a difference between two kinds of normativity: demanding and recommending normativity. But the crucial task is, of course, to explain the difference. In the second part of this paper, I suggest that metaethical expressivists can provide a good explanation: by extending the analysis of ordinary (non-normative) demands and recommendations to normative judgments, they can formulate a convincing account that captures the key differences between morality and rationality.     

Humean Naturalism and the Problem of Induction

Naturalised epistemology has shunned rationality, a hallmark of humanity since ancient Greece. One of Quine's explicit motivations is that Hume's problem of induction cannot be solved. However, Hume himself suggests a solution and the narrow focus of the paper is to present a 'Humean Solution' which is an elaboration and defence of Hume's suggestion. What emerges will be argued to be a naturalised conception of rationality which makes naturalised epistemology more continuous with traditional epistemology's focus on rationality.     

Coherence as an ideal of rationality

Probabilistic coherence is not an absolute requirement of rationality; nevertheless, it is an ideal of rationality with substantive normative import. An idealized rational agent who avoided making implicit logical errors in forming his preferences would be coherent. In response to the challenge, recently made by epistemologists such as Foley and Plantinga, that appeals to ideal rationality render probabilism either irrelevant or implausible, I argue that idealized requirements can be normatively relevant even when the ideals are unattainable, so long as they define a structure that links imperfect and perfect rationality in a way that enables us to make sense of the notion of better approximations to the ideal. I then analyze the notion of approximation to the ideal of coherence by developing a generalized theory of belief functions that allows for incoherence, and showing how such belief functions can be ordered with regard to greater or lesser coherence.Many people influenced the present version of this essay. Ban van Frassen, Richard Jeffrey, David Lewis, Mike Thau, and Alan Hájek provided extensive and invaluable written comments on the entire essay. Mark van Roojen provided helpful comments on Sections 3 and 4. Mike Than and John Barker provided essential aid when I was formulating the proofs in section 6. Finally, I am grateful for valuable discussion of the essay with Ned Hall, Fiona Cowie, Jim Woodward, David Hilbert, and Frank Arntzenius.     

Idealisations in normative models

In this paper I discuss the kinds of idealisations invoked in normative theories—logic, epistemology, and decision theory. I argue that very often the so-called norms of rationality are in fact mere idealisations invoked to make life easier. As such, these idealisations are not too different from various idealisations employed in scientific modelling. Examples of the latter include: fluids are incompressible (in fluid mechanics), growth rates are constant (in population ecology), and the gravitational influence of distant bodies can be ignored (in celestial mechanics). Thinking of logic, epistemology, and decision theory as normative models employing various idealisations of these kinds, changes the way we approach the justification of the models in question.     

The Accuracy and Rationality of Imprecise Credences

It has been claimed that, in response to certain kinds of evidence (“incomplete” or “non‐specific” evidence), agents ought to adopt imprecise credences: doxastic states that are represented by sets of credence functions rather than single ones. In this paper I argue that, given some plausible constraints on accuracy measures, accuracy‐centered epistemologists must reject the requirement to adopt imprecise credences. I then show that even the claim that imprecise credences are permitted is problematic for accuracy‐centered epistemology. It follows that if imprecise credal states are permitted or required in the cases that their defenders appeal to, then the requirements of rationality can outstrip what would be warranted by an interest in accuracy.     

Memory for goals: an activation‐based model

Goal‐directed cognition is often discussed in terms of specialized memory structures like the “goal stack.” The goal‐activation model presented here analyzes goal‐directed cognition in terms of the general memory constructs of activation and associative priming. The model embodies three predictive constraints: (1) the interference level, which arises from residual memory for old goals; (1) the strengthening constraint, which makes predictions about time to encode a new goal; and (3) the priming constraint, which makes predictions about the role of cues in retrieving pending goals. These constraints are formulated algebraically and tested through simulation of latency and error data from the Tower of Hanoi, a means‐ends puzzle that depends heavily on suspension and resumption of goals. Implications of the model for understanding intention superiority, postcompletion error, and effects of task interruption are discussed.     

Memory as a Generative Epistemic Source

It is widely assumed that memory has only the capacity to preserve epistemic features that have been generated by other sources. Specifically, if S knows (justifiedly believes/rationally believes) that p via memory at T2, then it is argued that (i) S must have known (justifiedly believed/rationally believed) that p when it was originally acquired at T1, and (ii) S must have acquired knowledge that p (justification with respect to p/rationality with respect to p) at T1 via a non-memorial source. Thus, according to this view, memory cannot make an unknown proposition known, an unjustified belief justified, or an irrational belief rational–it can only preserve what is already known, justified, or rational. In this paper, I argue that condition (i) is false and, a fortiori , that condition (ii) is false. Hence, I show that, contrary to received wisdom in contemporary epistemology, memory can function as a generative epistemic source.