Lina Eriksson

What are degrees of belief

AbstractProbabilism is committed to two theses: 1)Opinion comes in degrees—call them degrees of belief, or credences.2)The degrees of belief of a rational agent obey the probability calculus. Correspondingly, a natural way to argue for probabilism is: i)to give an account of what degrees of belief are, and then ii)to show that those things should be probabilities, on pain of irrationality. Most of the action in the literature concerns stage ii). Assuming that stage i) has been adequately discharged, various authors move on to stage ii) with varied and ingenious arguments. But an unsatisfactory response at stage i) clearly undermines any gains that might be accrued at stage ii) as far as probabilism is concerned: if those things are not degrees of belief, then it is irrelevant to probabilism whether they should be probabilities or not. In this paper we scrutinize the state of play regarding stage i). We critically examine several of the leading accounts of degrees of belief: reducing them to corresponding betting behavior (de Finetti); measuring them by that behavior (Jeffrey); and analyzing them in terms of preferences and their role in decision-making more generally (Ramsey, Lewis, Maher). We argue that the accounts fail, and so they are unfit to subserve arguments for probabilism. We conclude more positively: ‘degree of belief’ should be taken as a primitive concept that forms the basis of our best theory of rational belief and decision: probabilism.

Norms and conventions

What is the relation between norms (in the sense of ‘socially accepted rules’) and conventions? A number of philosophers have suggested that there is some kind of conceptual or constitutive relation between them. Some hold that conventions are or entail special kinds of norms (the ‘conventions-as-norms thesis’). Others hold that at least some norms are or entail special kinds of conventions (the ‘norms-as-conventions thesis’). We argue that both theses are false. Norms and conventions are crucially different conceptually and functionally in ways that make it the case that it is a serious mistake to try to assimilate them. They are crucially different conceptually in that whereas conventions are not normative and are behaviour dependent and desire dependent, norms are normative, behaviour independent, and desire independent. They are crucially different functionally in that whereas conventions principally serve the function of facilitating coordination, norms principally serve the function of making us accountable to one another.

The interference problem for the betting interpretation of degrees of belief

The paper’s target is the historically influential betting interpretation of subjective probabilities due to Ramsey and de Finetti. While there are several classical and well-known objections to this interpretation, the paper focuses on just one fundamental problem: There is a sense in which degrees of belief cannot be interpreted as betting rates. The reasons differ in different cases, but there’s one crucial feature that all these cases have in common: The agent’s degree of belief in a proposition A does not coincide with her degree of belief in a conditional that A would be the case if she were to bet on A, where the belief in this conditional itself is conditioned on the supposition that the agent will have an opportunity to make such a bet. Even though the two degrees of belief sometimes can coincide (they will coincide in those cases when the bet has no expected causal bearings on the proposition A and the opportunity to bet have no evidential bearings on that proposition), it is the latter belief rather than the former that guides the agent’s rational betting behaviour. The reason is that this latter belief takes into consideration potential interferences that bet opportunities and betting itself might create with regard to the proposition to be betted on. It is because of this interference problem that the agent’s degree of belief in A cannot be interpreted as her betting rate for A.

Charity, signaling, and welfare

Voices on the political right have long claimed that the welfare state ought to be kept small, and that charities can take over many of the tasks involved in helping those at the bottom of society. The arguments in favor of this claim are controversial, but even if they are accepted at face value the policy proposal remains problematic. For the proposal presupposes that charities would, in fact, be able to raise enough money to provide adequate help to those in need, and therefore assumes that charities are able to very significantly increase the number and/or size of donations they receive. We argue that there are good reasons for doubting that charities will be able to do this. Our argument turns on the fact that the most powerful strategy for eliciting donations—namely, allowing donors to use their donation to signal their pro-sociality—has an inbuilt upper limit. If too much emphasis is placed on the signaling opportunities donating to charity provides, donating no longer functions as an effective signal and the motivation to donate declines.

Social norms theory and development economics

Social norms affect almost every aspect of people’s lives, and can be an obstacle to or support economic development. This paper outlines what social norms are and how they work, providing examples from everyday life and from development case studies. Sometimes not much can be done about changing undesirable social norms. In those cases, development economists need to be aware of how the existence of those norms can impact the effects of the policies they advocate. But of particular importance to development economists is the ways in which social norms can be changed, at least under some circumstances. Understanding of social norm change is still patchy at best, but the paper outlines the theoretical underpinnings of change, with empirical evidence from various policies aimed at changing social norms. However, some of those policies raise ethical concerns that would require attention.

Betting Interpretation and the Problem of Interference

It has long been common to identify an agent’s degrees of belief with her betting rates. Here is this betting interpretation (BI) in a nutshell: A bet on a proposition A with price C and a non-zero stake S (= the monetary prize to be won by the bettor if A is true) is said to be fair for an agent iff the latter is willing to take each side of the bet, to buy the bet as to sell it. Assuming that such a bet on A exists and that the C/S ratio is constant for different fair bets on A, this ratio is the agent’s betting rate for A.