It is argued that we need a richer version of Bayesian decision theory, admitting both subjective and objective probabilities and providing rational criteria for choice of our prior probabilities. We also need a theory of tentative acceptance of empirical hypotheses. There is a discussion of subjective and of objective probabilities and of the relationship between them, as well as a discussion of the criteria used in choosing our prior probabilities, such as the principles of indifference and (...) of maximum entropy, and the simplicity ranking of alternative hypotheses. (shrink)

My claim that probability ought to be defined as a purely subjective measure of human belief has been challenged in a recent and interesting article on these pages by Arnold Baise . Baise argues that probability ought to be defined, not as a purely subjective measure of human belief, as I have claimed, but rather in the following way: Probability P is a number between 0 and 1 that indicates how plausible it is that proposition (...) A is true, based on information I. In addition, one could add that a probability of 1 indicates certainty that the proposition is true, while a probability of 0 indicates certainty that the proposition is false. .The reasoning that leads Baise to advance this definition for probability, however, is seriously and apodictically flawed. As a consequence, his definition for probability must be rejected as a viable alternative to my purely subjective definition. (shrink)

Confirmation is commonly identified with positive relevance, E being said to confirm H if and only if E increases the probability of H. Today, analyses of this general kind are usually Bayesian ones that take the relevant probabilities to be subjective. I argue that these subjective Bayesian analyses are irremediably flawed. In their place I propose a relevance analysis that makes confirmation objective and which, I show, avoids the flaws of the subjective analyses. What I (...) am proposing is in some ways a return to Carnap's conception of confirmation, though there are also important differences between my analysis and his. My analysis includes new accounts of what evidence is and of the indexicality of confirmation claims. Finally, I defend my analysis against Achinstein's criticisms of the relevance concept of confirmation. (shrink)

In this paper I present both a critical appraisal of Humphreys' probabilistic theory of causality and a sketch of an alternative view of the relationship between the notions of probability and of cause. Though I do not doubt that determinism is false, I claim that the examples used to motivate Humphreys' theory typically refer to subjective rather than objective chance. Additionally, I argue on a number of grounds that Humphreys' suggestion that linear regression models be used as (...) a canonical form for the description of causal relations is untenable. I conclude by exploring the variety of ways in which probabilistic elements can be embedded into the structure of causal mechanisms. This investigation suggests both that deterministic mechanisms can produce stochastic behavior and stochastic mechanisms can produce deterministic behavior. (shrink)

This article analyzes the role of entropy in Bayesian statistics, focusing on its use as a tool for detection, recognition and validation of eigen-solutions. “Objects as eigen-solutions” is a key metaphor of the cognitive constructivism epistemological framework developed by the philosopher Heinz von Foerster. Special attention is given to some objections to the concepts of probability, statistics and randomization posed by George Spencer-Brown, a figure of great influence in the field of radical constructivism.

In this paper I present both a critical appraisal of Humphreys' probabilistic theory of causality and a sketch of an alternative view of the relationship between the notions of probability and of cause. Though I do not doubt that determinism is false, I claim that the examples used to motivate Humphreys' theory typically refer to subjective rather than objective chance. Additionally, I argue on a number of grounds that Humphreys' suggestion that linear regression models be used as (...) a canonical form for the description of causal relations is untenable. I conclude by exploring the variety of ways in which probabilistic elements can be embedded into the structure of causal mechanisms. This investigation suggests both that deterministic mechanisms can produce stochastic behavior and stochastic mechanisms can produce deterministic behavior. Note: Link is to the article in a subscription database available to users affiliated with Butler University. Appropriate login information will be required for access. Users not affiliated with Butler University should contact their local librarian for assistance in locating a copy of this article. (shrink)

Objective probability in quantum mechanics is often thought to involve a stochastic process whereby an actual future is selected from a range of possibilities. Everett’s seminal idea is that all possible definite futures on the pointer basis exist as components of a macroscopic linear superposition. I demonstrate that these two conceptions of what is involved in quantum processes are linked via two alternative interpretations of the mind-body relation. This leads to a fission, rather than divergence, interpretation of Everettian (...) theory and to a novel explanation of why a principle of indifference does not apply to self-location uncertainty for a post-measurement, pre-observation subject, just as Sebens and Carroll claim. Their Epistemic Separability Principle is shown to arise out of this explanation and the derivation of the Born rule for Everettian theory is thereby put on a firmer footing. (shrink)

This paper offers a critique of the Bayesian interpretation of quantum mechanics with particular focus on a paper by Caves, Fuchs, and Schack containing a critique of the “objective preparations view” or OPV. It also aims to carry the discussion beyond the hardened positions of Bayesians and proponents of the OPV. Several claims made by Caves et al. are rebutted, including the claim that different pure states may legitimately be assigned to the same system at the same time, and (...) the claim that the quantum nature of a preparation device cannot legitimately be ignored. Both Bayesians and proponents of the OPV regard the time dependence of a quantum state as the continuous dependence on time of an evolving state of some kind. This leads to a false dilemma: quantum states are either objective states of nature or subjective states of belief. In reality they are neither. The present paper views the aforesaid dependence as a dependence on the time of the measurement to whose possible outcomes the quantum state serves to assign probabilities. This makes it possible to recognize the full implications of the only testable feature of the theory, viz., the probabilities it assigns to measurement outcomes. Most important among these are the objective fuzziness of all relative positions and momenta and the consequent incomplete spatiotemporal differentiation of the physical world. The latter makes it possible to draw a clear distinction between the macroscopic and the microscopic. This in turn makes it possible to understand the special status of measurements in all standard formulations of the theory. Whereas Bayesians have written contemptuously about the “folly” of conjoining “objective” to “probability,” there are various reasons why quantum-mechanical probabilities can be considered objective, not least the fact that they are needed to quantify an objective fuzziness. But this cannot be appreciated without giving thought to the makeup of the world, which Bayesians refuse to do. Doing this on the basis of how quantum mechanics assigns probabilities, one finds that what constitutes the macroworld is a single Ultimate Reality, about which we know nothing, except that it manifests the macroworld or manifests itself as the macroworld. The so-called microworld is neither a world nor a part of any world but instead is instrumental in the manifestation of the macroworld. Quantum mechanics affords us a glimpse “behind” the manifested world, at stages in the process of manifestation, but it does not allow us to describe what lies “behind” the manifested world except in terms of the finished product—the manifested world, for without the manifested world there is nothing in whose terms we could describe its manifestation. (shrink)

This paper pursues the question, To what extent does the propensity approach to probability contribute to plausible solutions to various anomalies which occur in quantum mechanics? The position I shall defend is that of the three interpretations — the frequency, the subjective, and the propensity — only the third accommodates the possibility, in principle, of providing a realistic interpretation of ontic indeterminism. If these considerations are correct, then they lend support to Popper's contention that the propensity construction tends (...) to remove (at least some of) the mystery from quantum phenomena. (shrink)

According to principles of probability coordination, such as Miller's Principle or Lewis's Principal Principle, you ought to set your subjective probability for an event equal to what you take to be the objective probability of the event. For example, you should expect events with a very high probability to occur and those with a very low probability not to occur. This paper examines the grounds of such principles. It is argued that any attempt (...) to justify a principle of probability coordination encounters the same difficulties as attempts to justify induction. As a result, no justification can be found. (shrink)

This essay offers an account of the truth conditions of sentences involving deontic modals like ‘ought’, designed to capture the difference between objective and subjective kinds of ‘ought’ This account resembles the classical semantics for deontic logic: according to this account, these truths conditions involve a function from the world of evaluation to a domain of worlds (equivalent to a so-called “modal base”), and an ordering of the worlds in such domains; this ordering of the worlds itself arises (...) from two further elements – a probability function and a value function – since this ordering ranks the worlds in accordance with the expected value of certain propositions that are true at those worlds. Thus, a proposition of the form ‘Ought (p)’ is true at a world of evaluation w if and only if p is true at all the top-ranked worlds in the domain assigned to w. This domain of worlds consists of metaphysically possible worlds, while the probability function is defined over a space of epistemically possible worlds (which may include metaphysically impossible worlds, such as worlds where Hesperus is not Phosphorus). Evidence is given that this account assigns the correct truth conditions to a wide range of sentences involving ‘ought’. Since these truth conditions involve both a domain of metaphysically possible worlds and a space of epistemically possible worlds, there are two corresponding kinds of conditional involving ‘ought’, depending on which space of worlds is restricted by the conditional. Finally, some objections that might be raised against this account are answered. (shrink)

Since utilities and probabilities jointly determine choices, event-dependent utilities complicate the elicitation of subjective event probabilities. However, for the usual purpose of obtaining the information embodied in agent beliefs, it is sufficient to elicit objective probabilities, i.e., probabilities obtained by updating a known common prior with that agent’s further information. Bayesians who play a Nash equilibrium of a certain insurance game before they obtain relevant information will afterward act regarding lottery ticket payments as if they had event-independent risk-neutral (...) utility and a known common prior. Proper scoring rules paid in lottery tickets can then elicit objective probabilities. (shrink)

In his Bayesian Nets and Causality, Jon Williamson presents an ‘Objective Bayesian’ interpretation of probability, which he endeavours to distance from the logical interpretation yet associate with the subjective interpretation. In doing so, he suggests that the logical interpretation suffers from severe epistemological problems that do not affect his alternative. In this paper, I present a challenge to his analysis. First, I closely examine the relationship between the logical and ‘Objective Bayesian’ views, and show how, and (...) why, they are highly similar. Second, I argue that the logical interpretation is not manifestly inferior, at least for the reasons that Williamson offers. I suggest that the key difference between the logical and ‘Objective Bayesian’ views is in the domain of the philosophy of logic; and that the genuine disagreement appears to be over Platonism versus nominalism. (shrink)

In this paper I address the question of whether the probabilities that appear in models of stochastic gene expression are objective or subjective. I argue that while our best models of the phenomena in question are stochastic models, this fact should not lead us to automatically assume that the processes are inherently stochastic. After distinguishing between models and reality, I give a brief introduction to the philosophical problem of the interpretation of probability statements. I argue that the (...) objective vs. subjective distinction is a false dichotomy and is an unhelpful distinction in this case. Instead, the probabilities in our models of gene expression exhibit standard features of both objectivity and subjectivity. (shrink)

This paper addresses the question of how we should regard the probability distributions introduced into statistical mechanics. It will be argued that it is problematic to take them either as purely subjective credences, or as objective chances. I will propose a third alternative: they are "almost objective" probabilities, or "epistemic chances". The definition of such probabilities involves an interweaving of epistemic and physical considerations, and so cannot be classified as either purely subjective or purely (...) class='Hi'>objective. This conception, it will be argued, resolves some of the puzzles associated with statistical mechanical probabilities; it explains how probabilistic posits introduced on the basis of incomplete knowledge can yield testable predictions, and it also bypasses the problem of disastrous retrodictions, that is, the fact the standard equilibrium measures yield high probability of the system being in equilibrium in the recent past, even when we know otherwise. As the problem does not arise on the conception of probabilities considered here, there is no need to invoke a Past Hypothesis as a special posit to avoid it. (shrink)

Subjective Bayesians typically find the following objection difficult to answer: some joint probability measures lead to intuitively irrational inductive behavior, even in the long run. Yet well-motivated ways to restrict the set of reasonable prior joint measures have not been forthcoming. In this paper I propose a way to restrict the set of prior joint probability measures in particular inductive settings. My proposal is the following: where there exists some successful inductive method for getting to the truth (...) in some situation, we ought to employ a (joint) probability measure that is inductively successful in that situation, if such a measure exists. In order to do show that the restriction is possible to meet in a broad class of cases, I prove a Bayesian Completeness Theorem, which says that for any solvable inductive problem of a certain broad type, there exist probability measures that a Bayesian could use to solve the problem. I then briefly compare the merits of my proposal with two other well-known proposals for constraining the class of admissible subjective probability measures, the leave the door ajar condition and the maximize entropy condition. (shrink)

This article sets forth and discusses the Ithaca Interpretation of Quantum Mechanics. Section 1 presents the standard formalism of quantum mechanics and the measurement problem. Section 2 sketches Everett's interpretation as a preamble to IIQM. Section 3 sets out IIQM's central claim: it is possible to make sense of quantum mechanics by taking as the proper subject of physics the correlations among subsystems. Section 4 introduces a theorem of quantum mechanics, the SSC theorem, which supports this claim. Section 5 contends (...) that at least two problems exist with IIQM, and one serious objection against it. Section 6 discusses a strategy based on relational probabilities to go around the objection. /// Este artículo presenta y discute la Interpretación de la Mecánica Cuántica de Ithaca. La sección 1 expone el formalismo estándar de la mecánica cuántica y el problema de la medición. La sección 2 bosqueja la interpretación de Everett como preámbulo a la IIQM. La sección 3 plantea la tesis central de la IIQM: es posible dar sentido a la mecánica cuántica tomando como sujeto propio de la física las correlaciones entre subsistemas. La sección 4 expone el teorema SSC de la mecánica cuántica que sustenta esta tesis. En la sección 5 se sostiene que existen al menos dos problemas con la IIQM, y una seria objeción en su contra. Para sortear esta objeción, la sección 6 discute una estrategia basada en probabilidades relacionales. (shrink)

In the Bayesian approach to quantum mechanics, probabilities—and thus quantum states—represent an agent’s degrees of belief, rather than corresponding to objective properties of physical systems. In this paper we investigate the concept of certainty in quantum mechanics. Particularly, we show how the probability-1 predictions derived from pure quantum states highlight a fundamental difference between our Bayesian approach, on the one hand, and Copenhagen and similar interpretations on the other. We first review the main arguments for the general claim (...) that probabilities always represent degrees of belief. We then argue that a quantum state prepared by some physical device always depends on an agent’s prior beliefs, implying that the probability-1 predictions derived from that state also depend on the agent’s prior beliefs. Quantum certainty is therefore always some agent’s certainty. Conversely, if facts about an experimental setup could imply agent-independent certainty for a measurement outcome, as in many Copenhagen-like interpretations, that outcome would effectively correspond to a preexisting system property. The idea that measurement outcomes occurring with certainty correspond to preexisting system properties is, however, in conflict with locality. We emphasize this by giving a version of an argument of Stairs [(1983). Quantum logic, realism, and value-definiteness. Philosophy of Science, 50, 578], which applies the Kochen–Specker theorem to an entangled bipartite system. (shrink)

In Probabilistic Knowledge Sarah Moss proposes that our credences and subjective probability judgments (SPJs) can constitute knowledge. Mossean probabilistic knowledge is grounded in probabilistic beliefs that are justified, true, and unGettiered. In this paper I aim to address and solve two challenges that arise in the vicinity of the factivity condition for probabilistic knowledge: the factivity challenge and the challenge from probabilistic arguments from ignorance (probabilistic AIs). I argue that while Moss's deflationary solution to the factivity challenge formally (...) works, it leaves us ill-equipped to handle probabilistic AIs. An account of probabilistic knowledge that cannot overcome probabilistic AIs makes knowledge of thoroughly probabilistic contents a rare and unstable phenomenon, at best, or, at worst, impossible. I hold that establishing a metaphysically enriched account of probabilistic truth is therefore mandatory. I go on to develop a truth-conditional approach on probabilistic factivity that is relativistic in its nature and centers on objective chances. I show that while the approach is still compatible with Moss's overall semantics for probabilistic knowledge, it provides us with a simple but forceful answer to probabilistic AIs. (shrink)

This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work is in the "public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work. Scholars believe, and we concur, that this work is important enough to be (...) preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant. (shrink)

Many definitions and theories of self assume that ‘self’ refers to some thing or process that exists as part of the universe. Similarly, ‘consciousness’ is assumed to refer to a property of such a part. These basic assumptions are mistaken, and generate some of the deepest confusions in the philosophy of mind. Such distinctions as seer/seen, hearer/heard, and thinker/thought generalize to subject/object. The distinction between subject and object is prior to any theories about the nature of the self: before I (...) can even begin to wonder what I am, I must have already realized that I am. Whatever I may call it cannot be conceived correctly as any kind of object or property. The distinction between subject and object is more fundamental than the Cartesian distinction between mind and matter, with which it is commonly conflated. ‘I am conscious’ and ‘I am’ are variant expressions of the same basic realization, suggesting that ‘consciousness’ and ‘being’ are convergent concepts. (shrink)

In this paper, I argue that certain perceptual relations are represented in visual experience.

In this paper, I explore the relationship between the subject and the object from the perspective of scientific realism. I first characterize the scientific realist position that I adopt. I then address the question of the nature of scientific knowledge from a realist point of view. Next I consider the question of how to locate the knowing subject within the context of scientific realism. After that I consider the place of mind in an objective world. I close with some (...) general remarks on the topic. (shrink)

A view widely held by epistemologists is that there is a distinction between subjective and objective epistemic justification, analogous to the commonly drawn distinction between subjective and objective justification in ethics. Richard Brandt offers a clear statement of this line of thought.

Subjects and Objects provides the philosophical groundwork for the determination of the limits ofion in art. This involves extensive consideration of the subject-object relationship and properties of subjects and objects that pertain to making and apprehending works of art.

The major competing statistical paradigms share a common remarkable but unremarked thread: in many of their inferential applications, different probability interpretations are combined. How this plays out in different theories of inference depends on the type of question asked. We distinguish four question types: confirmation, evidence, decision, and prediction. We show that Bayesian confirmation theory mixes what are intuitively “subjective” and “objective” interpretations of probability, whereas the likelihood-based account of evidence melds three conceptions of what constitutes (...) an “objective” probability. (shrink)

An extended analysis is given of the program, originally suggested by Deutsch, of solving the probability problem in the Everett interpretation by means of decision theory. Deutsch's own proof is discussed, and alternatives are presented which are based upon different decision theories and upon Gleason's Theorem. It is argued that decision theory gives Everettians most or all of what they need from `probability'. Contact is made with Lewis's Principal Principle linking subjective credence with objective chance: an (...) Everettian Principal Principle is formulated, and shown to be at least as defensible as the usual Principle. Some consequences of (Everettian) quantum mechanics for decision theory itself are also discussed. -/- [NB: this this long (70 pages) and occasionally rambling online-only paper has been almost entirely superseded by material in subsequent; if something is not included in them it usually means that I have had second thoughts. I include it for completeness only. (shrink)

This article examines how Žižek’s analysis of “subjective” violence can be used to explore the ways in which media coverage of a terrorist attack is contoured and shaped by less noticeable forms of “objective” (symbolic and systemic) violence. Drawing upon newspaper coverage of the 2017 London Bridge attack, it is noted how examples of “subjective” violence were grounded in the externalization of a clearly identifiable “other”, which symbolically framed the terrorists and the attack as tied to and (...) representative of the UK Muslim community. Examples of “systematic” violence were most notable in the ideological edifice that underpinned this framing but also in the ways in which newspaper reports served to draw upon British values in the aftermath of the attack. This directed attention away from the contradictions within the UK, towards narratives that sought to “fix” these contradictions through eradicating the problem of “the other” and/or by violently protecting the British values “they” seek to undermine. As a consequence, newspaper coverage worked to uphold the illusion that “peace” could be achieved by eradicating terrorism through further forms of objective violence, including, internment without trial; the “ripping up” of human rights; and, closer surveillance of Muslim communities. Indeed, it was this unacknowledged violence that worked to maintain British values in the press’ coverage. (shrink)

In this book Pollock deals with the subject of probabilistic reasoning, making general philosophical sense of objective probabilities and exploring their ...

Although the use of pronouns has been extensively investigated in children with autism spectrum disorders (ASD), most studies have focused on English, and no study to date has investigated the use of subject pronouns in null subject languages. The present study aims to fill this gap by investigating the use of subject and object pronouns in 5- to 8-year-old Greek-speaking high-functioning children with ASD compared to individually matched typically developing age and language controls. The ‘Frog where are you’ (Mayer, 1969) (...) narrative task was used to elicit subject and object pronouns as well as DPs. Greek is a null subject language, and as a result, subject pronouns most often remain without phonological content. The results showed that both groups used more null than overt subject pronouns, indicating that children with ASD know that Greek is a null subject language. TD children used more null subjects than subject DPs, whereas children with ASD used an equal proportion of null subjects and subject DPs. In terms of object pronouns, both groups produced more clitics and object DPs than strong object pronouns, but the difference between clitics and DPs did not reach significance in either of the groups. Importantly, the groups did not differ from each other in the use of ambiguous pronouns in both the subject and object position. The ASD children’s avoidance to use pronominal subjects can be taken as evidence that they use a strategy to avoid infelicitous reference. This would suggest that the ASD children’s difficulties with pronouns is not due to difficulties in core grammar. (shrink)

This reissue of D. A. Gillies highly influential work, first published in 1973, is a philosophical theory of probability which seeks to develop von Mises’ views on the subject. In agreement with von Mises, the author regards probability theory as a mathematical science like mechanics or electrodynamics, and probability as an objective, measurable concept like force, mass or charge. On the other hand, Dr Gillies rejects von Mises’ definition of probability in terms of limiting frequency (...) and claims that probability should be taken as a primitive or undefined term in accordance with modern axiomatic approaches. This of course raises the problem of how the abstract calculus of probability should be connected with the ‘actual world of experiments’. It is suggested that this link should be established, not by a definition of probability, but by an application of Popper’s concept of falsifiability. In addition to formulating his own interesting theory, Dr Gillies gives a detailed criticism of the generally accepted Neyman Pearson theory of testing, as well as of alternative philosophical approaches to probability theory. The reissue will be of interest both to philosophers with no previous knowledge of probability theory and to mathematicians interested in the foundations of probability theory and statistics. (shrink)

Many philosophers claimed that there might be fertile ground for collaboration between IBE and the objective end of the Bayesian methodology. Recent literature is investigated in this chapter, to highlight the latest developments about the possibility of such a collaboration. The merits of the convergence of the two methods are presented. It is argued that arriving on this end is not an easy goal as there are four ways by which subjective considerations may overshadow the objective picture. (...) The existence of subjective virtues, the vagueness of the mapping, the absence of an accurate weighting, and the existence of partial virtues allow the generation of infinitely many different initializations of priors and likelihoods, thus keeping the explanationist away from the objective extreme. Hence, either the explanationist successfully faces up with each one of the four problems so as to converge to the objective end or she ends up in a semi-objective position, whereby the explanatory restrictions allow a bunch of equally good probability distributions. (shrink)

Subject & Object is a thematic collection of classic works by Max Horkheimer, Theodor Adorno, and Herbert Marcuse, designed to foreground the authors' philosophical concerns, especially in the areas of epistemology, ontology, and method. The volume, which includes lucid introductions to all of the selections, illustrates Frankfurt School approaches to questions such as the nature of reason; the limits of empiricism, pragmatism and Kantian transcendental idealism; the case for materialism; the difficulty of thinking counterfactually; and the ideological character of mainstream (...) social science. Many of the pieces in the volume are otherwise out of print. Subject & Object will be a resource for social, political, and cultural theorists who may be less familiar with the philosophical aspects of the Frankfurt School, for analytic philosophers who may not have had previous exposure to their work at all, and for anyone wanting access to these seminal texts. (shrink)

This paper discusses different interpretations of probability in relation to determinism. It is argued that both objective and subjective views on probability can be compatible with deterministic as well as indeterministic situations. The possibility of a conceptual independence between probability and determinism is argued to hold on a general level. The subsequent philosophical analysis of recent advances in classical statistical mechanics is of independent interest, but also adds weight to the claim that it is possible (...) to justify an objective interpretation of probabilities in a theory having as a basis the paradigmatically deterministic theory of classical mechanics. (shrink)

Shows how Schopenhauer uses the concepts of subject and object to describe experience and knowledge and to argue for idealism. The world of things in space and time is the world as representation, comprised of objects for the subject. There can be no subject without object and no object without subject. Schopenhauer's argument that this supports idealism is assessed critically on the grounds that ‘no subject without object’ is ambiguous.

Probability can be used to measure degree of belief in two ways: objectively and subjectively. The objective measure is a measure of the rational degree of belief in a proposition given a set of evidential propositions. The subjective measure is the measure of a particular subject’s dispositions to decide between options. In both measures, certainty is a degree of belief 1. I will show, however, that there can be cases where one belief is stronger than another yet (...) both beliefs are plausibly measurable as objectively and subjectively certain. In ordinary language, we can say that while both beliefs are certain, one belief is more certain than the other. I will then propose second, non probabilistic dimension of measurement, which tracks this variation in certainty in such cases where the probability is 1. A general principle of rationality is that one’s subjective degree of belief should match the rational degree of belief given the evidence available. In this paper I hope to show that it is also a rational principle that the maximum stake size at which one should remain certain should match the rational weight of certainty given the evidence available. Neither objective nor subjective measures of certainty conform to the axioms of probability, but instead are measured in utility. This has the consequence that, although it is often rational to be certain to some degree, there is no such thing as absolute certainty. (shrink)