Luc Bovens

Suppose that we acquire various items of information from various sources and that our degree of confidence in the content of the information set is sufficiently high to believe the information. Now a new item of information is being presented by a new information source. Are we justified to add this new item of information to what we already believe? Consider the following parable: “I go to a lecture about wildlife in Greenland which was supposed to be delivered by an expert in the field. When I arrive I notice that the expert has excused himself and that the biology department has sent a newcomer to fill in for him. I have no beliefs about wildlife in Greenland, but I do have some beliefs about Greenland’s climate and about the kinds of climate conditions that various types of wildlife favor. Suppose that our newcomer proclaims that large colonies of elk roam in a particular valley on the southern tip of Greenland. Then I would certainly be willing to accept this item of information. But suppose that he proclaims that large colonies of armadillos roam in the same valley. Then I would not be willing to accept this item of information. Why do I accept the former but not the latter item of information? Let us suppose that neither item of information is logically inconsistent with what I already believe. Clearly, the former item of information is not inconsistent. But also the latter item is not: after all, there may be small pockets of Greenland with special climatological conditions and some Texan sailors may have set loose a pair of armadillos as a practical joke. But whereas the former item of information is quite plausible given my previous beliefs, the latter item of information is not. And this is what makes for the difference. Now suppose that our newcomer proclaims that large colonies of wild boars roam this valley in Greenland. I am not that sure anymore. Given everything I believe, I find wild boars in Greenland more plausible than armadillos in Greenland, but certainly less plausible than elk in Greenland. Had our expert presented the lecture and provided precisely the 2 same information, then I would have been willing to adopt the belief that there are wild boars in Greenland, but, with our newcomer delivering the lecture, I am not willing to do so. It is not that I would believe anything out of the expert’s mouth: also he could not have convinced me that there are armadillos in Greenland. But when it comes to wild boars, the difference between the expert’s and the newcomer’s credentials simply makes for the difference.” What we learn from this story is that the question of belief expansion has something to do with the reliability of the information source as well as with the plausibility of the new information, given what I already believe. The more reliable the information source is, the less plausible the new information needs to be given what I already believe, for me to be justified to add the belief to our belief set. The more plausible the new information is given what I already believe, the less reliable the information source needs to be given what I already believe, for me to be justified to add the belief to my belief set. The challenge is: can a precise account of this relationship be provided?

A committee has to address a complex question, the answer to which requires answering several sub-questions. Two different voting procedures can be used. On one procedure, the committee members vote on each sub-question and the voting results then are used as premises for the committee’s conclusion on the main issue. This premise-based procedure can be contrasted with the conclusion-based procedure. On that procedure, the members directly vote on the conclusion, with the vote of each member being guided by her views on the relevant sub-questions. These procedures are by no means equivalent, which has been pointed out in legal theory in connection with jury votes. There may be a majority of voters supporting each premise, but if these majorities do not significantly overlap, there will be a majority against the conclusion. Pettit connects the choice between the two procedures with general political theory, in particular, with the discussion of deliberative democracy. However, the problem we want to examine concerns the relative advantages and disadvantages of the two procedures from the epistemic point of view. In some cases one can assume that the question before the committee has the right answer. In cases like this, is one of the two procedures better when it comes to tracking the truth? As it turns out, the answer to this query is not univocal. On the basis of Condorcet’s jury theorem, we show that the premise-based procedure is clearly superior if the objective is reach truth for the right reasons, i.e. without making any mistakes on the way. However, if the goal instead is to reach truth for whatever reasons, right or wrong, there will be cases in which using the conclusion-based procedure turns out to be more reliable, even though, for the most part, the premise-based procedure will retain its superiority. Our results partly confirm and partly disconfirm the tentative conjectures that have been put forward in Pettit and Rabinowicz.

In the first part of this book Hausman defends a Millian view of the nature of economics. Economic models are deductive constructs based on principles that are arrived at through empirical generalization conjoined with simplifying assumptions. Economic theories are models put into practice by filling in economic data as initial conditions and by deducing predictions that are open to testing. If predictions fail, a reasoned account of the failure is due. Such an account consists in a critical examination of whether the premises of the deduction do justice to the economic reality at hand, and may lead to modifications in the theory.

Jon Elster contrasts preference acquisition through sour grapes with preference acquisition through character planning. He claims that what distinguishes these psychological phenomena is that only the latter is autonomous and intentional. I argue against this view and propose an alternative account which runs parallel to Donald Davidson's analysis of weakness of the will. On my account, preference acquisition through character planning secures the coherence between preferences and the reasons for holding these preferences, while preference acquisition through sour grapes does not. I then suggest that this account as well as moral theories that acknowledge conflicting moral concerns are threatened by alternative interpretations of Arrow's voting paradox in social choice theory. I discuss how appeals to various forms of moral supervenience , and, analogues to Amartya Sen's objections to a reading of Arrow's theorem in terms of social welfare judgments, affect these paradoxical interpretations. I argue that analogues to Sen's appeal to non-welfare information can dissolve these interpretations, though open the door for new threats from alternative interpretations of Sen's libertarian paradox