Sven Ove Hansson

In order to reduce the death toll of road traffic it is necessary to focus on how vehicles and roads can be improved. Like other dangerous machines, motor vehicles should be equipped with safety devices that prevent mistakes by the operator from leading to serious consequences. Speed limiters that prevent driving at illegal speeds would save many lives, and so would alcohol interlocks. Meshi Ori's proposal that most cars should be replaced by motorcycles would not lead to the moral improvement that he hopes for. We need motor vehicles with better, not worse, protection of the driver and passengers than the cars presently in use

Due to modern biochemistry and, in particular, recent developments in genomics, proteomics, and bioinformatics, human samples have become the most important raw materials for advancement in the health sciences. Such material has been at the center of fundamental biomedical research for a long time. What is new is its increased usefulness in research with direct clinical relevance, such as the development of drugs. Because of the larger commercial involvement in such research, this has also led to greater economic interests in human biological material and in the information that can be extracted from it

Traffic research shares a fundamental dilemma with other areas of empirical research in which humans are potentially put at risk. Research is justified because it can improve safety in the long run. Nevertheless, people can be harmed in the research situation. Hence, we need to balance short-term risks against long-term safety improvements, much as in other areas of research with human subjects. In this paper we focus on ethical issues that arise when human beings are directly affected in the performance of research by examining how the ethical requirements in biomedical research can inform traffic research. After introducing the basic ethical requirements on biomedical research, each of the major requirements is discussed in relation to traffic research. We identify the main areas where biomedical research and traffic research differ, and where the ethical requirements from the former cannot easily be transferred to the latter. Finally, we argue that there is a need for systematic studies of the ethics of traffic research and point to some of the issues that need to be addressed.

Farmers all over the world perform experiments, and have done so since long before modern experimental science and its recognized forerunners. There is a rich anthropological literature on these experiments, but the philosophical issues that they give rise to have not received much attention. Based on the anthropological literature, this study investigates methodological and philosophical issues pertaining to farmers’ experiments, including the choice of interventions to be tested, the planning of experiments, and the use of control fields and other means to deal with confounding factors. Farmers’ experiments have some advantages over the field trials of agricultural scientists, but also some comparative disadvantages. The two experimental traditions are complementary, and neither of them can replace the other. Several aspects of farmers’ experiments are shown to have a direct bearing on central topics in the philosophy of science.

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.

An operator of contraction for a belief set (a theory) can be obtained by assigning to it a belief base and an operator of partial meet contraction for that base. It is argued that closure of the base under disjunction is an intuitively reasonable condition. Axiomatic characterizations are given of the contractions of belief sets that can be generated by (various types of) partial meet contraction on disjunctively closed bases. The corresponding revision operators are also characterized. Finally, some results are reported on operations on bases that are closed under material implication.

Extended antipaternalism means the use of antipaternalist arguments to defend activities that harm (consenting) others. As an example, a smoker’s right to smoke is often invoked in defence of the activities of tobacco companies. It can, however, be shown that antipaternalism in the proper sense does not imply such extended antipaternalism. We may therefore approve of Mill’s antipaternalist principle (namely, that the only reason to interfere with someone’s behaviour is to protect others from harm) without accepting activities that harm (consenting) others. This has immediate consequences for the ethics of public health. An antipaternalist need not refrain from interfering with activities such as the marketing of tobacco or heroin, boxing promotion, driving with unbelted passengers, or buying sex from “voluntary” prostitutes

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.

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.

John Stuart Mill commented on the relationship between equality and liberty in general terms, and he also discussed the relationships between equality and four more concrete social goals: equality vs. diversity and individual spontaneity, equality vs. freedom of trade and entrepreneurial activity, equality vs. economic incentives for workpeople, and equality vs. welfare. In his more general statements he wrote off potential conflicts between equality and liberty, claiming that only those liberties that can be enjoyed by all are real liberties—or at least they are the only ones worth defending. However, in several of his more concrete discussions he gave higher priority to various liberty-related goals than to equality. This seeming contradiction can be resolved if we assume that he distinguished between valuing a liberty per se and valuing it as a means to achieve something else.

By replacement is meant an operation that replaces one sentence by another in a belief set. Replacement can be used as a kind of Sheffer stroke for belief change, since contraction, revision, and expansion can all be defined in terms of it. Replacement can also be defined either in terms of contraction or in terms of revision. Close connections are shown to hold between axioms for replacement and axioms for contraction and revision. Partial meet replacement is axiomatically characterized. It is shown that this operation can have outcomes that are not obtainable through either partial meet contraction or partial meet revision.

The typical function of goals is to regulate action in a way that furthers goal achievement. Goals are typically set on the assumption that they will help bring the agent closer to the desired state of affairs. However, sometimes endorsement of a goal, or the processes by which the goal is set, can obstruct its achievement. When this happens, the goal is self-defeating. Self-defeating goals are common in both private and social decision-making but have not received much attention by decision theorists. In this paper, we investigate different variants of three major types of self-defeating mechanisms: The goal can be an obstacle to its own fulfilment, goal-setting activities can impede goal achievement, and disclosure of the goal can interfere with its attainment. Different strategies against self-defeasance are tentatively explored, and their efficiency against different types of self-defeasance is investigated.

Real-life decision-making often begins with a disorderly decision problem that has to be clarified and systematized before a decision can be made. This is the process of decision structuring that has largely been ignored both in decision theory and applied decision analysis. In this contribution, ten major components of decision structuring are identified, namely the determination of its scope, subdivision, agency, timing, options, control ascriptions, framing, horizon, criteria and restructuring. Four of these components, namely the scope, subdivision, options, and horizon of a decision, are subjected to a more detailed analysis.