In the middle of the 1980s, logical tools were discovered that make it possible to model changes in belief and knowledge in entirely new ways. These logical tools turned out to be applicable both to human beliefs and to the contents of databases. This is the first textbook in this new area. It contains both discursive chapters with a minimum of formalism and formal chapters in which proofs and proof methods are presented. By using different selections from the formal section (...) the book can be used on all levels of University education. (shrink)

In standard Bayesian probability revision, the adoption of full beliefs (propositions with probability 1) is irreversible. Once an agent has full belief in a proposition, no subsequent revision can remove that belief. This is an unrealistic feature, and it also makes probability revision incompatible with belief change theory, which focuses on how the set of full beliefs is modified through both additions and retractions. This problem in probability theory can be solved in a model that (i) lets the codomain of (...) the probability function be a hyperreal-valued rather than the real-valued closed interval [0, 1], and (ii) identifies the full beliefs as the propositions whose probability is either 1 or infinitesimally smaller than 1. In this model, changes in the probability function will result in changes in the set of full beliefs (belief set), which constitutes a submodel that can be conceived as the “tip of the iceberg” within the larger model that also contains beliefs on lower levels of probability. The patterns of change in the set of full beliefs in this modified Bayesian model coincides with the corresponding pattern in a slightly modified version of AGM revision, which is commonly conceived as the gold standard of (dichotomous) belief change. The modification only concerns the marginal case of revision by an inconsistent input sentence. These results show that probability revision and dichotomous belief change can be unified in one and the same framework, or – if we so wish – that belief change theory can be subsumed under a modified version of probability revision that allows for iterated change and for the removal of full beliefs. (shrink)

Clear-cut cases of decision-making under risk (known probabilities) are unusual in real life. The gambler’s decisions at the roulette table are as close as we can get to this type of decision-making. In contrast, decision-making under uncertainty (unknown probabilities) can be exemplified by a decision whether to enter a jungle that may contain unknown dangers. Life is usually more like an expedition into an unknown jungle than a visit to the casino. Nevertheless, it is common in decision-supporting disciplines to proceed (...) as if reasonably reliable probability estimates were available for all possible outcomes, i.e. as if the prevailing epistemic conditions were analogous to those of gambling at the roulette table. This mistake can be called the tuxedo fallacy . It is argued that traditional engineering practices such as safety factors and multiple safety barriers avoid this fallacy and that they therefore manage uncertainty better than probabilistic risk analysis (PRA). PRA is a useful tool, but it must be supplemented with other methods in order not to limit the analysis to dangers that can be assigned meaningful probability estimates. (shrink)

When is it morally acceptable to expose others to risk? Most moral philosophers have had very little to say in answer to that question, but here is a moral philosopher who puts it at the centre of his investigations.

This book provides students with a toolbox for the study of the ethics of technology, exploring the methods available for ethical assessments of technologies and their social introduction. An international team of leading experts in the field provides the first comprehensive treatment of the topic, including case studies and annotated further reading.

Close connections between probability theory and the theory of belief change emerge if the codomain of probability functions is extended from the real-valued interval [0, 1] to a hyperreal interval with the same limits. Full beliefs are identified as propositions with a probability at most infinitesimally smaller than 1. Full beliefs can then be given up, and changes in the set of full beliefs follow a pattern very close to that of AGM revision. In this contribution, iterated revision is investigated. (...) The iterated changes in the set of full beliefs generated by repeated revisions of a hyperreal probability function can, semantically, be modelled with the same basic structure as the sphere models of belief change theory. The changes on the set of full beliefs induced by probability revision satisfy the Darwiche–Pearl postulates for iterated belief change. (shrink)

A new formal model of belief dynamics is proposed, in which the epistemic agent has both probabilistic beliefs and full beliefs. The agent has full belief in a proposition if and only if she considers the probability that it is false to be so close to zero that she chooses to disregard that probability. She treats such a proposition as having the probability 1, but, importantly, she is still willing and able to revise that probability assignment if she receives information (...) that gives her sufficient reasons to do so. Such a proposition is undoubted, but not undoubtable. In the formal model it is assigned a probability 1 − δ, where δ is an infinitesimal number. The proposed model employs probabilistic belief states that contain several underlying probability functions representing alternative probabilistic states of the world. Furthermore, a distinction is made between update and revision, in the same way as in the literature on belief change. The formal properties of the model are investigated, including properties relevant for learning from experience. The set of propositions whose probabilities are infinitesimally close to 1 forms a belief set. Operations that change the probabilistic belief state give rise to changes in this belief set, which have much in common with traditional operations of belief change. (shrink)

Clear-cut cases of decision-making under risk (known probabilities) are unusual in real life. The gambler’s decisions at the roulette table are as close as we can get to this type of decision-making. In contrast, decision-making under uncertainty (unknown probabilities) can be exemplified by a decision whether to enter a jungle that may contain unknown dangers. Life is usually more like an expedition into an unknown jungle than a visit to the casino. Nevertheless, it is common in decision-supporting disciplines to proceed (...) as if reasonably reliable probability estimates were available for all possible outcomes, i.e. as if the prevailing epistemic conditions were analogous to those of gambling at the roulette table. This mistake can be called the tuxedo fallacy. It is argued that traditional engineering practices such as safety factors and multiple safety barriers avoid this fallacy and that they therefore manage uncertainty better than probabilistic risk analysis (PRA). PRA is a useful tool, but it must be supplemented with other methods in order not to limit the analysis to dangers that can be assigned meaningful probability estimates. (shrink)

The introduction of self-driving vehicles gives rise to a large number of ethical issues that go beyond the common, extremely narrow, focus on improbable dilemma-like scenarios. This article provides a broad overview of realistic ethical issues related to self-driving vehicles. Some of the major topics covered are as follows: Strong opinions for and against driverless cars may give rise to severe social and political conflicts. A low tolerance for accidents caused by driverless vehicles may delay the introduction of driverless systems (...) that would substantially reduce the risks. Trade-offs will arise between safety and other requirement on the road traffic system. Over-reliance on the swift collision-avoiding reactions of self-driving vehicles can induce people to take dangerous actions, such as stepping out in front of a car, relying on its fast braking. Children travelling alone can violate safety instructions such as the use of seatbelts. Digital information about routes and destinations can be used to convey commercial and political messages to car users. If fast passage can be bought, then socio-economic segregation of road traffic may result. Terrorists and other criminals can hack into a vehicle and make it crash. They can also use self-driving vehicles for instance to carry bombs to their designed places of detonation or to wreak havoc on a country’s road system. (shrink)

This is a reply to a comment by Kåre Letrud [Letrud, Kåre. 2019. “The Gordian Knot of Demarcation: Tying Up Some Loose Ends.” International Studies in the Philosophy of Science 32 : 3–11. doi:10...

It has been much debated whether epistemic relativism in academia, for instance in the form of social constructivism, the strong programme, deconstructionism, and postmodernism, has paved the way for the recent upsurge in science denial, in particular climate science denial. In order to provide an empirical basis for this discussion, an extensive search of the social science literature was performed. It showed that in the 1990s, climate science was a popular target among academic epistemic relativists. In particular, many STS scholars (...) used it as an allegedly clear example of claims by natural scientists that should be treated as mere social constructions, rather than as reports on the actual state of the natural world. A few connections between social constructivists and corporate science denialism were also uncovered, but the extent of such connections could not be determined. With few exceptions, the stream of criticism of climate science from academic relativists has dwindled since the 1990s. One reason for this seems to be that the contrarian position lost its attraction when it became associated with corporate and right-wing propagandists. (shrink)

What purpose can be served by empirically unsubstantiated speculation in ethics? In answering that question, we need to distinguish between the major branches of ethics. In foundational moral philosophy, the use of speculative examples is warranted to the extent that ethical principles and theories are assumed to be applicable even under the extreme circumstances referred to in these examples. Such an assumption is in need of justification, and it cannot just be taken for granted. In applied ethics, the use of (...) unrealistic scenarios is more difficult to justify. It can be positively harmful if it diverts our attention from more urgent issues. Neuroethics is one of the areas of applied ethics where speculative scenarios have taken up much of the attention that could instead have been devoted to problems that are relevant for the treatment and care of patients. Speculative ethics has often been defended with mere possibility arguments that may at first hand seem difficult to refute. It is shown with examples how such claims can be defeated with a combination of science and argumentation analysis. (shrink)

The precautionary principle has often been described as an extreme principle that neglects science and stifles innovation. However, such an interpretation has no support in the official definitions of the principle that have been adopted by the European Union and by the signatories of international treaties on environmental protection. In these documents, the precautionary principle is a guideline specifying how to deal with certain types of scientific uncertainty. In this contribution, this approach to the precautionary principle is explicated with the (...) help of concepts from the philosophy of science and comparisons with general notions of practical rationality. Three major problems in its application are discussed, and it is concluded that to serve its purpose, the precautionary principle has to (1) be combined with other decision principles in cases with competing top priorities, (2) be based on the current state of science, which requires procedures for scientific updates, and (3) exclude potential dangers whose plausibility is too low to trigger meaningful precautionary action. (shrink)

A definition of pseudoscience is proposed, according to which a statement is pseudoscientific if and only if it (1) pertains to an issue within the domains of science, (2) is not epistemically warranted, and (3) is part of a doctrine whose major proponents try to create the impression that it is epistemically warranted. This approach has the advantage of separating the definition of pseudoscience from the justification of the claim that science represents the most epistemically warranted statements. The definition is (...) used to explain why proponents of widely divergent criteria for the demarcation between science and pseudoscience tend to be in almost complete agreement on the particular demarcations that should presumably be based on these general criteria. (shrink)

The purpose of this presentation is to introduce both the concept of risk and the precautionary principle, that is a major policy principle in present-day risk management. Since risk has been the subject of many misconceptions I will do this in large part by criticizing seven views on risk that I believe to have caused considerable confusion both among scientists and policy-makers. But before looking at the seven myths of risk, let us begin with the basic issue of defining “risk”. (...) The word “risk” often refers, rather vaguely, to situations in which it is possible but not certain that some undesirable event will occur. In addition, the word has several more specialized meanings. Let me illustrate this by making a few statements about the single most important preventable health hazard in non-starving countries. First: “Lung cancer is one of the major risks that affect smokers.” Here, we use “risk” in the following sense: (1) risk = an unwanted event which may or may not occur. 1 (15). (shrink)

This article is an attempt at a systematic account of decision making under greater uncertainty than what traditional, mathematically oriented decision theory can cope with. Four components of great uncertainty are distinguished: (1) the identity of the options is not well determined (uncertainty of demarcation) ; (2) the consequences of at least some option are unknown (uncertainty of consequences); (3) it is not clear whether information obtained from others, such as experts, can be relied on (uncertainty of reliance); and (4) (...) the values relevant for the decision are not determined with sufficient precision (uncertainty of values). Some possible strategy types are proposed for each of these components. Decisions related to environmental issues are used to illustrate the proposals. (shrink)

This article investigates the properties of multistate top revision, a dichotomous model of belief revision that is based on an underlying model of probability revision. A proposition is included in the belief set if and only if its probability is either 1 or infinitesimally close to 1. Infinitesimal probabilities are used to keep track of propositions that are currently considered to have negligible probability, so that they are available if future information makes them more plausible. Multistate top revision satisfies a (...) slightly modified version of the set of basic and supplementary AGM postulates, except the inclusion and success postulates. This result shows that hyperreal probabilities can provide us with efficient tools for overcoming the well known difficulties in combining dichotomous and probabilistic models of belief change. (shrink)

The volume analyses and develops David Makinson’s efforts to make classical logic useful outside its most obvious application areas. The book contains chapters that analyse, appraise, or reshape Makinson’s work and chapters that develop themes emerging from his contributions. These are grouped into major areas to which Makinsons has made highly influential contributions and the volume in its entirety is divided into four sections, each devoted to a particular area of logic: belief change, uncertain reasoning, normative systems and the resources (...) of classical logic. Among the contributions included in the volume, one chapter focuses on the “inferential preferential method”, i.e. the combined use of classical logic and mechanisms of preference and choice and provides examples from Makinson’s work in non-monotonic and defeasible reasoning and belief revision. One chapter offers a short autobiography by Makinson which details his discovery of modern logic, his travels across continents and reveals his intellectual encounters and inspirations. The chapter also contains an unusually explicit statement on his views on the role of logic in philosophy. (shrink)

Clinical Ethics, Ahead of Print. It could hardly be denied that healthcare should be patient-centred. However, some of the practices commonly described as patient-centred care may have ethically problematic consequences. This article identifies and discusses twelve ethical conflicts that may arise in the application of person-centred care. The conflicts concern e.g. privacy, autonomous decision-making, safeguarding medical quality, and maintaining professional egalitarianism as well as equality in care. Awareness of these potential conflicts can be helpful in finding the best way to (...) ensure that healthcare has its focus on the needs and interests of the patients. Patient-centred care may have to take different forms, depending of the nature of the disease, the patient’s life situation, and the economic, organizational and technological resources available to the healthcare unit. (shrink)

BackgroundWith the increased use of implanted medical devices follows a large number of explantations. Implants are removed for a wide range of reasons, including manufacturing defects, recovery making the device unnecessary, battery depletion, availability of new and better models, and patients asking for a removal. Explantation gives rise to a wide range of ethical issues, but the discussion of these problems is scattered over many clinical disciplines.MethodsInformation from multiple clinical disciplines was synthesized and analysed in order to provide a comprehensive (...) approach to the ethical issues involved in the explantation of medical implants.ResultsDiscussions and recommendations are offered on pre-implantation information about a possible future explantation, risk–benefit assessments of explantation, elective explantations demanded by the patient, explantation of implants inserted for a clinical trial, patient registers, quality assurance, routines for investigating explanted implants, and demands on manufacturers to prioritize increased service time in battery-driven implants and to market fewer but more thoroughly tested models of implants.ConclusionSpecial emphasis is given to the issue of control or ownership over implants, which underlies many of the ethical problems concerning explantation. It is proposed that just like transplants, implants that fulfil functions normally carried out by biological organs should be counted as supplemented body parts. This means that the patient has a strong and inalienable right to the implant, but upon explantation it loses that status. (shrink)

Mainstream moral theories deal with situations in which the outcome of each possible action is well-determined and knowable. In order to make ethics relevant for problems of risk and uncertainty, moral theories have to be extended so that they cover actions whose outcomes are not determinable beforehand. One approach to this extension problem is to develop methods for appraising probabilistic combinations of outcomes. This approach is investigated and shown not to solve the problem. An alternative approach is then developed. Its (...) starting-point is that everyone has a prima facie moral right not to be exposed to risk. However, this right can be overridden if the risk-exposure is part of an equitable system for risk-taking that works to the advantage of the individual risk-exposed person. (shrink)

Blockage contraction is an operation of belief contraction that acts directly on the outcome set, i.e. the set of logically closed subsets of the original belief set K that are potential contraction outcomes. Blocking is represented by a binary relation on the outcome set. If a potential outcome X blocks another potential outcome Y, and X does not imply the sentence p to be contracted, then Y ≠ K ÷ p. The contraction outcome K ÷ p is equal to the (...) (unique) inclusion-maximal unblocked element of the outcome set that does not imply p. Conditions on the blocking relation are specified that ensure the existence of such a unique inclusion-maximal set for all sentences p. Blockage contraction is axiomatically characterized and its relations to AGM-style operations are investigated. In a finite-based framework, every transitively relational partial meet contraction is also a blockage contraction. (shrink)

In the first part of this paper, I clear the ground from frequent misconceptions of the relationship between fact and value by examining some uses of the adjective “natural” in ethical controversies. Such uses bear evidence to our “natural” tendency to regard nature as the source of ethical norms. I then try to account for the origins of this tendency by offering three related explanations, the most important of which is evolutionistic: if any behaviour that favours our equilibrium with the (...) environment is potentially adaptive, nothing can be more effective for this goal than developing an attitude toward the natural world that considers it as a dispenser of sacred norms that must be invariably respected. By referring to the Aristotelian notion of human flourishing illustrated in the first part of the paper, in the second I discuss as a case study some ethical problems raised by mini-chips implantable in our bodies. I conclude by defending their potential beneficial effects of such new technological instruments. (shrink)

A descriptor is a set of sentences that are truth-functional combinations of expressions of the form \ , where \ is a metalinguistic belief predicate and p a sentence in the object language in which beliefs are expressed. Descriptor revision ) is an operation of belief change that takes us from a belief set K to a new belief set \ where \ is a descriptor representing the success condition. Previously studied operations of belief change are special cases of descriptor (...) revision, hence sentential revision can be represented as \ , contraction as \ , multiple contraction as \ , replacement as \ , etc. General models of descriptor revision are constructed and axiomatically characterized. The common selection mechanisms of AGM style belief change cannot be used, but they can be replaced by choice functions operating directly on the set of potential outcomes . The restrictions of this construction to sentential revision ) and sentential contraction give rise to operations with plausible properties that are also studied in some some detail. (shrink)

This introduction to formal philosophy has its focus on the basic methodology of formalization: the selection of concepts for formalization, appropriate splittings and merges of concepts to be formalized, the idealization that is necessary prior to formalization, the identification of variables and their domains, and the construction of a formal language. Other topics covered in this chapter are the advantages and pitfalls of formal philosophy, the relationships between formal models and that which they represent, and the use of non-logical models (...) in philosophy. (shrink)

Multiple contraction (simultaneous contraction by several sentences) and iterated contraction are investigated in the framework of specified meet contraction (s.m.c.) that is extended for this purpose. Multiple contraction is axiomatized, and so is finitely multiple contraction (contraction by a finite set of sentences). Two ways to reduce finitely multiple contraction to contraction by single sentences are introduced. The reduced operations are axiomatically characterized and their properties are investigated. Furthermore, it is shown how iterated contraction can be reduced to single-step, single-sentence (...) contraction. However, in this framework the outcome of iterated contraction depends unavoidably on the order in which the inputs are received. This order-dependence makes it impossible to treat two inputs on an equal footing. Therefore it is often preferable to perform changes involving several pieces of information as multiple rather than iterated change. (shrink)

ABSTRACT John Rawls proposed two criteria for the delimitation of acceptable inequalities. The universal gain principle requires inequalities to be beneficial for all, and the difference principle requires them to be beneficial for the least advantaged. These principles are commonly believed to have originated in Rawls’s work, but they were both clearly expressed in the writings of Nicolas de Condorcet. Contrary to Rawls, Condorcet did not imbed them in the framework of a social contract, but instead sought their foundations in (...) natural rights. Whereas Rawls recommends us to find out what social arrangements rational reasoners would choose in a hypothetical pre-social situation, Condorcet proposes that we ask the underprivileged in our society whether or not they consider themselves to benefit from the prevailing social and economic inequalities. Thus, Condorcet’s original version of the difference principle puts social inequalities to a different test than its latter-day, hypothetical version. (shrink)

The public defence of science has never been more important than now. However, it is a difficult task with many pitfalls, and there are mechanisms that can make it counterproductive. This article offers advice for science defenders, summarized in ten commandments that warn against potentially ineffective or even backfiring practices in the defence of science: Do not portray science as a unique type of knowledge. Do not underestimate scientific uncertainty. Do not describe science as infallible. Do not deny the value-ladenness (...) of science. Do not associate with power. Do not blame the victims of disinformation. Do not aim at convincing the anti-scientific propagandists. Do not contribute to the legitimization of pseudoscience. Do not attack religion when it does not conflict with science. Do not call yourself a “sceptic”. (shrink)

The relatively new discipline of risk analysis promises to provide objective guidance in some of the most controversial issues in modern high‐technology societies. Four conditions are discussed that must be satisfied for this promise to be fulfilled. Since none of these conditions is satisfied, risk analysis does not keep its promise. In its attempts to reduce genuinely political issues to technocratic calculations, it neglects many of the factors that should influence decisions on risk acceptance. A list of tentative guidelines is (...) given for numerical decision support that encourages democratic decision‐making instead of trying to evade it. (shrink)

Cost–benefit analysis (CBA) is much more philosophically interesting than has in general been recognized. Since it is the only well-developed form of applied consequentialism, it is a testing-ground for consequentialism and for the counterfactual analysis that it requires. Ten classes of philosophical problems that affect the practical performance of cost–benefit analysis are investigated: topic selection, dependence on the decision perspective, dangers of super synopticism and undue centralization, prediction problems, the indeterminateness of our control over future decisions, the need to exclude (...) certain consequences for moral reasons, bias in the delimitation of consequences, incommensurability of consequences, difficulties in defending the essential requirement of transferability across contexts, and the normatively questionable but equally essential assumption of interpersonal compensability. (Published Online July 31 2007). (shrink)

It is almost universally acknowledged that risks have to be weighed against benefits, but there are different ways to perform the weighing. In conventional risk analysis, collectivist risk-weighing is the standard. This means that an option is accepted if the sum of all individual benefits outweighs the sum of all individual risks. In practices originating in clinical medicine, such as ethical appraisals of clinical trials, individualist risk-weighing is the standard. This implies a much stricter criterion for risk acceptance, namely that (...) the risk to which each individual is exposed should be outweighed by benefits for that same individual. The different choices of risk-weighing methods in different policy areas seem to have emerged from traditional thought patterns and social relations, rather than from explicit deliberations on possible justifications for the alternative ways to weigh risks against benefits. It is not obvious how the prevalent differences in risk-weighing practices can be reconstructed in terms of consistent underlying principles of preventive health or social priority-setting. (shrink)

The postulate of recovery is commonly regarded to be the intuitively least compelling of the six basic Gärdenfors postulates for belief contraction. We replace recovery by the seemingly much weaker postulate of core-retainment, which ensures that if x is excluded from K when p is contracted, then x plays some role for the fact that K implies p. Surprisingly enough, core-retainment together with four of the other Gärdenfors postulates implies recovery for logically closed belief sets. Reasonable contraction operators without recovery (...) do not seem to be possible for such sets. Instead, however, they can be obtained for non-closed belief bases. Some results on partial meet contractions on belief bases are given, including an axiomatic characterization and a non-vacuous extension of the AGM closure condition. (shrink)

The AGM (Alchourrón-Gärdenfors-Makinson) model of belief change is extended to cover changes on sets of beliefs that are not closed under logical consequence (belief bases). Three major types of change operations, namely contraction, internal revision, and external revision are axiomatically characterized, and their interrelations are studied. In external revision, the Levi identity is reversed in the sense that one first adds the new belief to the belief base, and afterwards contracts its negation. It is argued that external revision represents an (...) intuitively plausible way of revising one's beliefs. Since it typically involves the temporary acceptance of an inconsistent set of beliefs, it can only be used in belief representations that distinguish between different inconsistent sets of belief. (shrink)

In non-technical contexts, the word “risk” refers, often rather vaguely, to situations in which it is possible but not certain that some undesirable event will occur. In technical contexts, the word has many uses and specialized meanings. The most common ones are the following.

Theoria, Volume 87, Issue 1, Page 3-6, February 2021.

Our uncertainty about matters of fact can often be adequately represented by probabilities, but there are also cases in which we, intuitively speaking, know too little even to assign meaningful probabilities. In many of these cases, other formal representations can be used to capture some of the prominent features of our uncertainty. This is a non-technical overview of some of these representations, including probability intervals, belief functions, fuzzy sets, credal sets, weighted credal sets, and second order probabilities.