This brief paperback is designed for symbolic/formal logic courses. It features the tree method proof system developed by Jeffrey. The new edition contains many more examples and exercises and is reorganized for greater accessibility.
Richard Jeffrey is beyond dispute one of the most distinguished and influential philosophers working in the field of decision theory and the theory of knowledge. His work is distinctive in showing the interplay of epistemological concerns with probability and utility theory. Not only has he made use of standard probabilistic and decision theoretic tools to clarify concepts of evidential support and informed choice, he has also proposed significant modifications of the standard Bayesian position in order that it provide a (...) better fit with actual human experience. Probability logic is viewed not as a source of judgment but as a framework for explaining the implications of probabilistic judgments and their mutual compatability This collection of essays spans a period of some 35 years and includes what have become some of the classic works in the literature. There is also one completely new piece, while in many instances Jeffrey includes afterthoughts on the older essays. (shrink)
According to the free-will defence, the exercise of free will by creatures is of such value that God is willing to allow the existence of evil which comes from the misuse of free will. A well-known objection holds that the exercise of free will is compatible with determinism and thus, if God exists, God could have predetermined exactly how the will would be exercised; God could even have predetermined that free will would be exercised sinlessly. Thus, it is held, the (...) free-will defence cannot be used as a partial account of why God should have allowed evil to exist. I investigate this objection using Kripke's apparatus for treating modalities and natural kinds to explore the nature of the incompatibilism required by the free-will defence. I show why the objection fails even if the standard arguments for compatibilism are acceptable. This is because the modality involved in the incompatibilism needed by the free-will defence differs from the modality involved in the compatibilism that is supported by standard compatibilist arguments. Finally, an argument is sketched for a variety of incompatibilism of the kind needed by the free-will defence. (shrink)
There is a conception of hell that holds that God punishes some people in a way that brings about endless suffering and unhappiness. An objection to this view holds that such punishment could not be just since it punishes finite sins with infinite suffering. In answer to this objection, it is shown that endless suffering, even intense suffering, is consistent with the suffering being finite. Another objection holds that such punishment is contrary to God's love. A possible response to this (...) objection is developed. (shrink)
In this paper I argue that the most prominent and familiar features of Wittgenstein’s rule following considerations generate a powerful argument for the thesis that most of our concepts are innate, an argument that echoes a Chomskyan poverty of the stimulus argument. This argument has a significance over and above what it tells us about Wittgenstein’s implicit commitments. For, it puts considerable pressure on widely held contemporary views of concept learning, such as the view that we learn concepts by constructing (...) prototypes. This should lead us to abandon our general default hostility to concept nativism and be much more sceptical of claims made on behalf of learning theories. (shrink)
Radical Concept Nativism (RCN) is the doctrine that most of our concepts are innate. In this paper I will argue in favour of RCN by developing a speculative account of concept acquisition that has considerable nativist credentials and can be defended against the most familiar anti-nativist objections. The core idea is that we have a whole battery of hard-wired dispositions that determine how we group together objects with which we interact. In having these dispositions we are effectively committed to an (...) implicit conceptual scheme and acquiring concepts is a matter of labelling the elements of that scheme. (shrink)
It is well known that the following features hold of AR + T under the strong Kleene scheme, regardless of the way the language is Gödel numbered: 1. There exist sentences that are neither paradoxical nor grounded. 2. There are 2ℵ0 fixed points. 3. In the minimal fixed point the weakly definable sets (i.e., sets definable as {n∣ A(n) is true in the minimal fixed point where A(x) is a formula of AR + T) are precisely the Π1 1 sets. (...) 4. In the minimal fixed point the totally defined sets (sets weakly defined by formulae all of whose instances are true or false) are precisely the ▵1 1 sets. 5. The closure ordinal for Kripke's construction of the minimal fixed point is ωCK 1. In contrast, we show that under the weak Kleene scheme, depending on the way the Gödel numbering is chosen: 1. There may or may not exist nonparadoxical, ungrounded sentences. 2. The number of fixed points may be any positive finite number, ℵ0, or 2ℵ0 . 3. In the minimal fixed point, the sets that are weakly definable may range from a subclass of the sets 1-1 reducible to the truth set of AR to the Π1 1 sets, including intermediate cases. 4. Similarly, the totally definable sets in the minimal fixed point range from precisely the arithmetical sets up to precisely the ▵1 1 sets. 5. The closure ordinal for the construction of the minimal fixed point may be ω, ωCK 1, or any successor limit ordinal in between. In addition we suggest how one may supplement AR + T with a function symbol interpreted by a certain primitive recursive function so that, irrespective of the choice of the Godel numbering, the resulting language based on the weak Kleene scheme has the five features noted above for the strong Kleene language. (shrink)
Edited by three leading figures in the field, this exciting volume presents cutting-edge work in decision theory by a distinguished international roster of contributors. These mostly unpublished papers address a host of crucial areas in the contemporary philosophical study of rationality and knowledge. Topics include causal versus evidential decision theory, game theory, backwards induction, bounded rationality, counterfactual reasoning in games and in general, analyses of the famous common knowledge assumptions in game theory, and evaluations of the normal versus extensive form (...) formulations of complex decision problems. (shrink)
Much controversy has surrounded the use of animals in research. Empirically, much of the research has focused on how ethical individuals believe animal research to be, but it has not systematically examined the specific beliefs or reasons why individuals do or do not believe animal research to be ethical. Study 1 investigated the thematic foundations for the decision that animal research is or is not ethical by examining the content of essays written by participants explaining why they do or do (...) not support the use of animals in research. Results indicated that individuals who believed animal research was ethical most often referenced beliefs that animal research furthered human well-being, provided mechanisms to cure disease, and was well-regulated. Individuals who believed animal research was not ethical most often referenced beliefs that animal research was inhumane, unnecessary, and nonconsensual. Study 2 used the themes to create a scale to assess animal research attitudes. (shrink)
"To some people, life is very simple . . . no shadings and grays, all blacks and whites. . . . Now, others of us find that good, bad, right, wrong, are many-sided, complex things. We try to see every side; but the more we see, the less sure we are.".
In Unifying Biology, Smocovitis offers a series of claimsregarding the relationship between key actors in the synthesisperiod of evolutionary studies and positivism, especially claimsentailing Joseph Henry Woodger and the Unity of Science Movement.This commentary examines Woodger''s possible relevance to key synthesis actors and challenges Smocovitis'' arguments for theexplanatory relevance of logical positivism, and positivism moregenerally, to synthesis history. Under scrutiny, these arguments areshort on evidence and subject to substantial conceptual confusion.Though plausible, Smocovitis'' minimal interpretation – that somegeneralised form of Comtean (...) positivism had a role in synthesishistory – requires more of an evidential basis and must engageexisting scholarship on epistemic reforms in the biological sciencesprior to the synthesis period. Smocovitis is right to investigateepistemology in the synthesis period of evolutionary studies and tolook for links to wider changes in science and philosophy. However,in its present form, Unifying Biology fails to support herbasic interpretation. (shrink)
From a point of view like de Finetti's, what is the judgmental reality underlying the objectivistic claim that a physical magnitude X determines the objective probability that a hypothesis H is true? When you have definite conditional judgmental probabilities for H given the various unknown values of X, a plausible answer is sufficiency, i.e., invariance of those conditional probabilities as your probability distribution over the values of X varies. A different answer, in terms of conditional exchangeability, is offered for use (...) when such definite conditional probabilities are absent. (shrink)
Jerry Fodor is one of the most important philosophers of mind in recent decades. He has done much to set the agenda in this field and has had a significant influence on the development of cognitive science. Fodor's project is that of constructing a physicalist vindication of folk psychology and so paving the way for the development of a scientifically respectable intentional psychology. The centrepiece of his engagement in this project is a theory of the cognitive mind, namely, the computational (...) theory of mind, which postulates the existence of a language of thought. Fodor: Language, Mind and Philosophy is a comprehensive study of Fodor's writings. Individual chapters are devoted to each of the major issues raised by his work and contain extensive discussion of his relationships to key developments in cognitive science and to the views of such philosophical luminaries as Dennett, Davidson and Searle. (shrink)
The approach to decision theory floated in my 1965 book is reviewed (I), challenged in various related ways (II–V) and defended, firstad hoc (II–IV) and then by a general argument of Ellery Ells's (VI). Finally, causal decision theory (in a version sketched in VII) is exhibited as a special case of my 1965 theory, according to the Eellsian argument.
Isaac Levi and I have different views of probability and decision making. Here, without addressing the merits, I will try to answer some questions recently asked by Levi (1985) about what my view is, and how it relates to his.
Logicism Lite counts number‐theoretical laws as logical for the same sort of reason for which physical laws are counted as as empirical: because of the character of the data they are responsible to. In the case of number theory these are the data verifying or falsifying the simplest equations, which Logicism Lite counts as true or false depending on the logical validity or invalidity of first‐order argument forms in which no numbertheoretical notation appears.
In this paper I address an important question concerning the nature of visual content: are the contents of human visual states and experiences exhaustively fixed or determined (in the non-causal sense) by our intrinsic physical properties? The individualist answers this question affirmatively. I will argue that such an answer is mistaken. A common anti-individualist or externalist tactic is to attempt to construct a twin scenario involving humanoid duplicates who are embedded in environments that diverge in such a way that it (...) appears to be necessary to attribute divergent contents to their respective visual states. In the first half of the paper I discuss some of the twin scenarios that are prominent in the literature and argue that they fail to undermine individualism. Indeed I argue that due to important facts about our internal workings, a convincing externalist twin scenario involving humanoid protagonists cannot be constructed. However, I argue that such a result does not conclusively establish an individualist thesis and that in order to settle the question at issue it is necessary to construct an independently motivated theory of visual content. I attempt to do this in the second half of the paper by developing a theory at the core of which is the idea that the contents of our visual states and experiences are determined by the causal powers vis-. (shrink)
Selection type theories solve adaptation problems. Natural selection, clonal selection for antibody production, and selective theories of higher brain function are examples. An abstract characterization of typical selection processes is generated by analyzing and extending previous work on the nature of natural selection. Once constructed, this abstraction provides a useful tool for analyzing the nature of other selection theories and may be of use in new instances of theory construction. This suggests the potential fruitfulness of research to find other theory (...) types and construct their abstractions. (shrink)
This essay explicates the role of countersystem analysis as an essential mode of social inquiry. In the process, particular attention is given to the place of negation and the future. One underlying theme is the asymmetry between the negative and the positive features of social activities, the negative being more readily identifiable empirically than the positive. A corollary theme, building on the observations of George Herbert Mead, is: one engages the present through experience; one engages the future through ideas. Furthermore, (...) as Anthony Giddens, Ulrich Beck, and Niklas Luhmann suggest, we in late modernity seem to be facing a future that is more contingent than it was in early modernity. After articulating the foundations of the mode of inquiry we term "countersystem analysis," we employ Karl Mannheim as a point of departure for critically surveying a constellation of scholars-conservatives as well as reformers-who have relied upon some version of countersystem analysis in addressing the future. Such an orientation serves to advance not only theoretical inquiry but empirical investigation as well. (shrink)
The Committee on Common Problems of Genetics, Paleontology, and Systematics (United States National Research Council) marks part of a critical transition in American evolutionary studies. Launched in 1942 to facilitate cross-training between genetics and paleontology, the Committee was also designed to amplify paleontologist voices in modern studies of evolutionary processes. During coincidental absences of founders George Gaylord Simpson and Theodosius Dobzhansky, an opportunistic Ernst Mayr moved into the project's leadership. Mayr used the opportunity for programmatic reforms he had been pursuing (...) elsewhere for more than a decade. These are evident in the Bulletins he distributed under Committee auspices. In his brief tenure as Committee leader, Mayr gained his first substantial foothold within the coalescing community infrastructure of evolutionary studies. Carrying this momentum forward led Mayr directly into the project to launch the journal Evolution. The sociology of interdisciplinary activity provides useful tools for understanding the Committee's value in the broad sweep of change in evolutionary studies during the synthesis period. (shrink)
The European Union welfare standardsfor intensively kept pigs have steadilyincreased over the past few years and areproposed to continue in the future. It isimportant that the cost implications of thesechanges in welfare standards are assessed. Theaim of this study was to determine theprofitability of rearing pigs in a range ofhousing systems with different standards forpig welfare. Models were constructed tocalculate the cost of pig rearing (6–95 kg) in afully-slatted system (fulfilling minimum EUspace requirements, Directive 91630/EEC); apartly-slatted system; a high-welfare,straw-based system (...) (complying with the UK-basedRoyal Society for the Prevention of Cruelty toAnimals, Freedom Food standards) and afree-range system. The models were also used toassess the consequences of potential increasesin space allowance, and to estimate the cost ofrearing pigs under organic standards.The cost of rearing pigs ranged from92.0 p/kg carcass weight (cw) and 94.6 p/kgcw forthe partly-slatted and fully-slatted systems,to 98.8 p/kgcw and 99.3 p/kgcw for the FreedomFood and free-range systems respectively. Whenspace allowance was increased by 60% to levelsin a recent proposal to revise pig welfareDirective (91/630/EEC), the rearing costs wereunchanged for the free-range system but rose by4.6 p/kgcw for the fully-slatted system. Rearingcosts under organic standards were 31% higherthan in the free-range system. These resultssuggest that improved pig welfare can beachieved with a modest increase in cost. (shrink)
Ernst Mayr''s contributions to 20th century biology extend far beyond his defense of certain elements in evolutionary theory. At the center of mid-century efforts in American evolutionary studies to build large research communities, Mayr spearheaded campaigns to create a Society for the Study of Evolution and a dedicated journal,Evolution, in 1946. Begun to offset the prominence ofDrosophila biology and evolutionary genetics, these campaigns changed course repeatedly, as impediments appeared, tactics shifted, and compromises built a growing coalition of support. Preserved, however, (...) were designs to balance the community and journal with careful equation of status and explicit partitioning of responsibilities within the working coalition. Choice terms such as cooperation and unity carried a strong political message. Mayr''s editorship ofEvolution provides a superb example of these balancing efforts. The mid-century infrastructural activities described herein also represented aggressive attempts to leverage control across several layers of community. Leaders of these campaigns sought: (1) to promote evolutionary studies as a modernized research discipline and place it at the center of American biology, (2) to promote evolutionary studies within existing disciplines — e.g. systematics, genetics, and paleontology, (3) to foster certain research styles within evolutionary studies, and (4) to emphasize certain solutions to prominent research questions. Throughout, Mayr interjected his priorities, tactics and energy. (shrink)
REPORT OF MEETINGS OF THE COMMITTEE ON COMMON PROBLEMS OF GENETICS AND PALEONTOLOGY {]oint Committee of the Divisions of Geology and Geography. and Biology ...
Shors and Matzel's evaluation of approaches to the behavioural function of LTP is welcome, and should encourage a widening of conceptual approaches to this problem. In addition to their call for increased sophistication in thinking about LTP, there needs to be a parallel increase in sophistication in the study of behaviour. Changes in emotional state or tone may be a better function for LTP than attention mechanisms.
Justifying ethical practices is no easy task. This paper considers moral justifications for peer review so as to persuade even the sceptical individualist. Two avenues provide a foundation for that justification: self-interest (the right behaviour is that which maximally serves one’s own interests) and social contract theory (the right behaviour is that which best meets obligations set in binding social contracts). A wider notion of “interest” permits the self-interest approach to justify not only submitting one’s own work to peer review (...) but also removing oneself momentarily from the production of primary knowledge to serve as a rigorous, independent, and honest referee. The contract approach offers a non-selfish alternative and relies on four types of binding social contracts: those implicit in accepting funds, those implicit in asserted professional status, those to contribute what is of most value to society, and those to defend the ideals of the Academy. Efforts to restore respect for rigorous, independent, honest peer review should begin in earnest. (shrink)
Conflicts of interest can lead experts to give biased and corrupt advice. Although disclosure is often proposed as a potential solution to these problems, we show that it can have perverse effects. First, people generally do not discount advice from biased advisors as much as they should, even when advisors’ conflicts of interest are disclosed. Second, disclosure can increase the bias in advice because it leads advisors to feel morally licensed and strategically encouraged to exaggerate their advice even further. As (...) a result, disclosure may fail to solve the problems created by conflicts of interest and may sometimes even make matters worse. (shrink)
This book offers a concise survey of basic probability theory from a thoroughly subjective point of view whereby probability theory is a mode of judgement. Written by one of the greatest figures in the field of probability theory, the book is both a summation and a synthesis of a lifetime of wrestling with such problems and issues.
Jonathan Weisberg has argued that Jeffrey Conditioning is inherently “anti-holistic” By this he means, inter alia, that JC does not allow us to take proper account of after-the-fact defeaters for our beliefs. His central example concerns the discovery that the lighting in a room is red-tinted and the relationship of that discovery to the belief that a jelly bean in the room is red. Weisberg’s argument that the rigidity required for JC blocks the defeating role of the red-tinted light (...) rests on the strong assumption that all posteriors within the distribution in this example are rigid on a partition over the proposition that the jelly bean is actually red. But individual JC updates of propositions do not require such a broad rigidity assumption. Jeffrey conditionalizers should consider the advantages of a modest project of targeted updating focused on particular propositions rather than seeking to update the entire distribution using one obvious partition. Although Weisberg’s example fails to show JC to be irrelevant or useless, other problems he raises for JC (the commutativity and inputs problems) remain and actually become more pressing when we recognize the important role of background information. (shrink)
This paper discusses simultaneous belief updates. I argue here that modeling such belief updates using the Principle of Minimum Information can be regarded as applying Jeffrey conditionalization successively, and so that, contrary to what many probabilists have thought, the simultaneous belief updates can be successfully modeled by means of Jeffrey conditionalization.
Bayesian decision theory can be viewed as the core of psychological theory for idealized agents. To get a complete psychological theory for such agents, you have to supplement it with input and output laws. On a Bayesian theory that employs strict conditionalization, the input laws are easy to give. On a Bayesian theory that employs Jeffrey conditionalization, there appears to be a considerable problem with giving the input laws. However, Jeffrey conditionalization can be reformulated so that the problem (...) disappears, and in fact the reformulated version is more natural and easier to work with on independent grounds. (shrink)
Richard Jeffrey's generalization of Bayes' rule of conditioning follows, within the theory of belief functions, from Dempster's rule of combination and the rule of minimal extension. Both Jeffrey's rule and the theory of belief functions can and should be construed constructively, rather than normatively or descriptively. The theory of belief functions gives a more thorough analysis of how beliefs might be constructed than Jeffrey's rule does. The inadequacy of Bayesian conditioning is much more general than Jeffrey's (...) examples of uncertain perception might suggest. The ``parameter α '' that Hartry Field has introduced into Jeffrey's rule corresponds to the "weight of evidence" of the theory of belief functions. (shrink)
Since the beginning of the ?eighties of the present century, a circle of relatively young American sociologists who are followers of Jeffrey Alexander are making energetic and spectacular efforts to supply sociology with a uniform and comprehensive theoretical framework by continuing Talcott Parsons' lifework. The present article is an appreciation of Alexander's achievements in the justification of a general sociological theory (especially a theory of action and social order) while pointing to objections that can be raised against the character (...) of his theory. A scrutiny of Alexander's metatheoretical deliberations and of his interpretations of sociological classics such as Marx, Durkheim, Weber, and Parsons reveals that Alexander's metatheoretical frame is not flexible enough to actually reconstruct the problem situation of the classics. Pointers are given toward a theory of action that is not subject to the antinomy of utilitarianism and normativism, so that it is more adequate and appropriate to the heritage of the sociological classics, both from a theoretical and an interpretative angle. (shrink)
In Tsuji 1997 the concept of Jeffrey-Keynes algebras was introduced in order to construct a paraconsistent theory of decision under uncertainty. In the present paper we show that these algebras can be used to develop a theory of decision under uncertainty that measures the degree of belief on the quasi (or partial) truth of the propositions. As applications of this new theory of decision, we use it to analyze Popper's paradox of ideal evidence and to indicate a possible way (...) of formalizing Keynes' theory of economic action. (shrink)
This paper is partly a tribute to Richard Jeffrey, partly a reflection on some of his writings, The Logic of Decision in particular. I begin with a brief biography and some fond reminiscences of Dick. I turn to some of the key tenets of his version of Bayesianism. All of these tenets are deployed in my discussion of his response to the St. Petersburg paradox, a notorious problem for decision theory that involves a game of infinite expectation. Prompted by (...) that paradox, I conclude with some suggestions of avenues for future research. (shrink)
Abstract. Suppose that several individuals who have separately assessed prior probability distributions over a set of possible states of the world wish to pool their individual distributions into a single group distribution, while taking into account jointly perceived new evidence. They have the option of (i) first updating their individual priors and then pooling the resulting posteriors or (ii) first pooling their priors and then updating the resulting group prior. If the pooling method that they employ is such that they (...) arrive at the same final distribution in both cases, the method is said to be externally Bayesian, a property first studied by Madansky (1964). We show that a pooling method for discrete distributions is externally Bayesian if and only if it commutes with Jeffrey conditioning, parameterized in terms of certain ratios of new to old odds, as in Wagner (2002), rather than in terms of the posterior probabilities of members of the disjoint family of events on which such conditioning originates. (shrink)
Jeffrey Stout addresses two of the main criticisms of liberal democracy by its contemporary neotraditionalist Christian critics: that liberal democracy is destructive of social tradition, and thereby of virtue in the citizenry, and that liberal democracy is inherently secular, committed to expunging religious voices from the public arena. I judge that Stout effectively answers these charges: liberal democracy has its own tradition, it cultivates the virtues relevant to that, and it is not inherently hostile to piety. What Stout does (...) not do, I suggest, is take the next step of showing, positively, that Christianity can and should affirm the substance of liberal democratic society. This is due, in good measure, to the fact that Stout never tells us, except in off-hand comments, what he takes the substance of liberal democracy to be. And this, in turn, is due to his way of employing pragmatism: he uses pragmatism to give an account of human society generally, not of liberal democratic society. I raise some questions about the general account that pragmatism gives of human society, and thus about the account that it would give of liberal democracy. (shrink)
Zoologist A. J. Cain began historical research on Linnaeus in 1956 in connection with his dissatisfaction over the standard taxonomic hierarchy and the rules of binomial nomenclature. His famous 1958 paper 'Logic and Memory in Linnaeus's System of Taxonomy' argues that Linnaeus was following Aristotle's method of logical division without appreciating that it properly applies only to 'analysed entities' such as geometric figures whose essential nature is already fully known. The essence of living things being unanalysed, there is (...) no basis on which to choose the right characters to define a genus nor on which to differentiate species. Yet Cain's understanding of Aristotle, which depended on a 1916 text by H. W. B. Joseph, was fatally flawed. In the 1990s Cain devoted himself to further historical study and softened his verdict on Linnaeus, praising his empiricism. The idea that Linnaeus was applying an ancient and inappropriate method cries out for fresh study and revision. (shrink)
A glance at the sky raises my probability of rain to .7. As it happens, the conditional probabilities of each state given rain remain the same, and similarly for their conditional probabilities given no rain. As Jeffrey (1983, Ch. 11) points out, my new distribution P2 is therefore fixed by the law of total probability. For example, P2(RC) = P2(RC | R)P2(R)+P2(RC | ¯.
Jeffrey Tillman is perceptive in noticing that certain Protestant theologians have used evolutionary theory to become more sympathetic to Roman Catholic views of Christian love. But he is incorrect in saying that these formulations deemphasize a place for self-sacrifice in Christian love. Christian love defined as a strenuous equal-regard for both other and self also requires sacrificial efforts to restore love as equal-regard when finitude and sin undermine genuine mutuality and community.
To the Editor: It was with great interest that our Canadian Palliative Sedation Therapy Guideline working group read Jeffrey Berger's recent article ("Rethinking Guidelines for the Use of Palliative Sedation," May-June 2010). Given our own group's efforts to develop national guidelines, we have rethought the issue of palliative sedation therapy several times over the past year.The use of clear and concise definitions is fundamental to the development of any consensus guidelines on this topic. In the article, the term "palliative (...) sedation to unconsciousness," or PSU, implies the concerning assumption that sedation will knowingly be to unconsciousness in the palliative case under consideration. This conflicts with .. (shrink)
Jeffrey (1983) proposed a generalization of conditioning as a means of updating probability distributions when new evidence drives no event to certainty. His rule requires the stability of certain conditional probabilities through time. We tested this assumption (“invariance”) from the psychological point of view. In Experiment 1 participants offered probability estimates for events in Jeffrey’s candlelight example. Two further scenarios were investigated in Experiment 2, one in which invariance seems justified, the other in which it does not. Results (...) were in rough conformity to Jeffrey (1983)’s principle. (shrink)
A simple rule of probability revision ensures that the final result of a sequence of probability revisions is undisturbed by an alteration in the temporal order of the learning prompting those revisions. This Uniformity Rule dictates that identical learning be reflected in identical ratios of certain new-to-old odds, and is grounded in the old Bayesian idea that such ratios represent what is learned from new experience alone, with prior probabilities factored out. The main theorem of this paper includes as special (...) cases (i) Field's theorem on commuting probability-kinematical revisions and (ii) the equivalence of two strategies for generalizing Jeffrey's solution to the old evidence problem to the case of uncertain old evidence and probabilistic new explanation. (shrink)
I show that David Lewis’s principal principle is not preserved under Jeffrey conditionalization. Using this observation, I argue that Lewis’s reason for rejecting the desire as belief thesis and Adams’s thesis applies also to his own principal principle. 1 Introduction2 Adams’s Thesis, the Desire as Belief Thesis, and the Principal Principle3 Jeffrey Conditionalization4 The Principal Principles Not Preserved under Jeffrey Conditionalization5 Inadmissible Experiences.
James Cain issues forth a two-pronged attack against classical forms of act utilitarianism, elucidating objections from infinite utility streams and distributive justice through his novel examples.1 In his first example, we are to imagine an infinite number of immortals, living on an infinitely long street (Elm Street), bracing to suffer an infinite amount of migraine pain with the onset of this horrific disease. Left untreated, the disease would wreak havoc among our immortals in the following way. Year 1: P1 (...) Year 2: P1, P2, P3 Year 3: P1, P2, P3, P4, P5, P6, P7 Year 4: P1, P2, P3, P4, P5, P6, P7, P8, P9, P10, P11, P12, P13, P14, P15.. (shrink)
Richard Jeffrey and Michael Goldstein have both introduced systematic approaches to the structure of opinion changes. For both approaches there are theorems which indicate great generality and width of scope. The main questions addressed here will be to what extent the basic forms of representation are intertranslatable, and how we can conceive of such programs in general.
Many strands are woven into the ideas and work of Jeffrey Gray. From a background of classical languages and a spell in military intelligence spent honing skills in languages and typing, he took two BA degrees (in modern languages and psychology) at Oxford University. He then trained as a clinical psychologist at the Institute of Psychiatry (IOP), London, capping this with a PhD on the sources of emotional behaviour.
Suppose n Bayesian agents need to make a decision as a group. The groupas a whole is also supposed to be a Bayesian agent whose probabilities andutilities are derived or aggregated in reasonable ways from the probabilitiesand utilities of the group members. The aggregation could beex ante, i.e., interms of expected utilities, or it could be ex post, i.e., in terms of utilitiesonly, or in terms of utilities and probabilities separately. This study exploresthe ex post approach. Using the Bolker/Jeffrey (...) framework, we show thatex post aggregation is subject to an instability phenomenon. That is, it mayhappen that the group preference between actions ``flips back and forth'''' dependingon the level of detail in which the decision problem is described. Structurally verysimilar phenomena also occur elsewhere in social choice theory, in statistics (Simpson''sParadox), and in voting theory (Ostrogorski''s Paradox). (shrink)
In this commentary, after first summarizing the three major theses of Jeffrey's paper Probability and Falsification: Critique of the Popper Program, and sketching out what I take to be his central argument, I criticize Jeffrey on two grounds. The first is that he has failed to explain why his version of Bayesianism provides us with better theories upon which to make decisions; the second is that he has offered a theory about decision-making that by-passes the important question: How (...) can we make more rational decisions? (shrink)
(2013). Review of Jeffrey P. Spike, Thomas R. Cole, Richard Buday, Freeman Williams, and Mary Ann Pendino, The Brewsters. The American Journal of Bioethics: Vol. 13, No. 3, pp. 52-54. doi: 10.1080/15265161.2013.760988.
In this paper, I argue for a view largely favorable to the Thirder view: when Sleeping Beauty wakes up on Monday, her credence in the coin’s landing heads is less than 1/2. Let’s call this “the Lesser view.” For my argument, I (i) criticize Strict Conditionalization as the rule for changing de se credences; (ii) develop a new rule; and (iii) defend it by Gaifman’s Expert Principle. Finally, I defend the Lesser view by making use of this new rule.
