The arguments for Bayesianism in the literature fall into three broad categories. There are Dutch Book arguments, both of the traditional pragmatic variety and the modern ‘depragmatised’ form. And there are arguments from the so-called ‘representation theorems’. The arguments have many similarities, for example they have a common conclusion, and they all derive epistemic constraints from considerations about coherent preferences, but they have enough differences to produce hostilities between their proponents. In a recent paper, Maher (1997) has argued that the (...) pragmatised Dutch Book arguments are unsound and the depragmatised Dutch Book arguments question begging. He urges we instead use the representation theorem argument as in his (1993). In this paper I argue that Maher’s own argument is question-begging, though in a more subtle and interesting way than his Dutch Book wielding opponents. (shrink)

Uncertainty plays an important role in The General Theory, particularly in the theory of interest rates. Keynes did not provide a theory of uncertainty, but he did make some enlightening remarks about the direction he thought such a theory should take. I argue that some modern innovations in the theory of probability allow us to build a theory which captures these Keynesian insights. If this is the right theory, however, uncertainty cannot carry its weight in Keynes’s arguments. This does not (...) mean that the conclusions of these arguments are necessarily mistaken; in their best formulation they may succeed with merely an appeal to risk. (shrink)

This dissertation looks at a set of interconnected questions concerning the foundations of probability, and gives a series of interconnected answers. At its core is a piece of old-fashioned philosophical analysis, working out what probability is. Or equivalently, investigating the semantic question of what is the meaning of ‘probability’? Like Keynes and Carnap, I say that probability is degree of reasonable belief. This immediately raises an epistemological question, which degrees count as reasonable? To solve that in its full generality would (...) mean the end of human inquiry, so that won’t be attempted here. Rather I will follow tradition and merely investigate which sets of partial beliefs are coherent. -/- The standard answer to this question, what is commonly called the Bayesian answer, says that degrees of belief are coherent iff they form a probability function. I disagree with the way this is usually justified, but subject to an important qualification I accept the answer. The important qualification is that degrees of belief may be imprecise, or vague. Part one of the dissertation, chapters 1 to 6, looks largely at the consequences of this qualification for the semantic and epistemological questions already mentioned. It turns out that when we allow degrees of belief to be imprecise, we can discharge potentially fatal objections to some philosophically attractive theses. Two of these, that probability is degree of reasonable belief and that the probability calculus provides coherence constraints on partial beliefs, have been mentioned. Others include the claim, defended in chapter 4, that chance is probability given total history. -/- As well as these semantic and epistemological questions, studies of the foundations of probability usually include a detailed discussion of decision theory. For reasons set out in chapter 2, I deny we can gain epistemological insights from decision theory. Nevertheless, it is an interesting field to study on its own, and it might be expected that there would be decision theoretic consequences of allowing imprecise degrees of belief. As I show in part two, this expectation seems to be mistaken. Chapter 9 shows that there aren’t interesting consequences of this theory for decision theory proper, and chapters 10 and 11 show that Keynes’s attempt to use imprecision in degrees of belief to derive a distinctive theory of interest rates is unsound. -/- Chapters 7 and 8 provide a link between these two parts. In chapter 7 I look at some previous philosophical investigations into the effects of imprecision. In chapter 8 I develop what I take to be the best competitor to the theory defended here – a constructivist theory of probability. On this view degrees of belief are precise, but the relevant coherence constraint is a constructivist probability calculus. This view is, I think, mistaken, but the calculus has some intrinsic interest, and there are at least enough arguments for it to warrant a chapter-length examination. (shrink)

The so-called diet and patch models were foundational for evolutionary studies of foraging ecology. The diet model analyzed an organism’s choice between at least two different food or prey items. The patch model asked how much time a forager should invest in exploiting a resource patch that offered diminishing returns before moving on to search for another patch. Concerning sources of inspiration, however, some pioneers of optimal foraging theory explicitly denied an input from economics, others explicitly credited marginalist economics, while (...) the majority remained tacit on this issue. An inquiry into the historical sources reveal an interesting patter. As far as diet is concerned, at least two models existed. One was the, probably homegrown, so-called contingency model of diet choice, the other was imported from marginal utility theory of economics. The import could not be operationalized in a way allowing predictions about feeding behavior. It was, therefore, used as a framework for interpreting data on food choices and gaining insights about the relative value of food items. The contingency model was hypothetico-deductive instead. It allowed predictions of behavior that could be tested. It was, therefore, the more popular among the peers and the pioneering publications have become citation classics, whereas the publications importing marginal utility theory int foraging ecology are largely forgotten. The situation is different for the patch model. At face value, only one homegrown model exists that was discovered independently at least twice. A closer look reveals obscure links suggesting knowledge dispersal from marginal productivity theory of economics towards optimal foraging or mating theory, respectively, along routes of private and unpublished communications. These communications were between alma mater and student in the case of Eric Charnov and between father and son, in the case of Geoffrey Parker. This study suggests two concusions: 1. models that are operationalized in a way allowing hypothetico-deductive research are more popular among researchers than others requiring a more inductive an interpretive approach. 2. The sciences are interlinked far more closely and deeply than mere citations would suggest. Sometimes a knowledge transfer that is crucial for a discovery can occur as an informal and private communication. (shrink)

Orthodox Bayesian decision theory requires an agent’s beliefs representable by a real-valued function, ideally a probability function. Many theorists have argued this is too restrictive; it can be perfectly reasonable to have indeterminate degrees of belief. So doxastic states are ideally representable by a set of probability functions. One consequence of this is that the expected value of a gamble will be imprecise. This paper looks at the attempts to extend Bayesian decision theory to deal with such cases, and concludes (...) that all proposals advanced thus far have been incoherent. A more modest, but coherent, alternative is proposed. Keywords: Imprecise probabilities, Arrow’s theorem. (shrink)

This study sheds a light on economic roots of optimal foraging/mating theory. Two examples show graphical optimisation models of behavioural ecology that are identical to much older ones of economics. The knowledge transfer has been conscious and explicit in some cases, but also less visible in others. This does no imply plagiarism or misconduct but merely shows how knowledge can diffuse along obscure, sometimes unconscious, routes of non-public and private communication.

The integration of learning cognitive agents in the research agenda is an important step in the evolution of economics. However, relying on a retrospective analysis of the treatment of decision making in economics, this article argues that the cognitive programme aims to justify rational behaviour in an equilibrium framework rather than to integration an interpretative conception of agents' behaviour. As a consequence, the level of generality of analytical results remains limited and economists miss the opportunity to establish a discussion with (...) other social sciences. In particular, it fails to analyse a class of situations related to the problem of knowledge creation and the subsequent learning paradox. Building on recent advances in heterodox cognitive science, we suggest a behavioural approach that discriminates different learning situations. If applied, this approach would permit a better understanding of human behaviour and a richer analysis of coordination mechanisms in unfamiliar environment with no loss of rigour. (shrink)

From a sociological perspective, Rational Choice Theory neglects an important question: How do agents come to conceptualise choices as they do? In particular, agents not only communicate about their choices and resulting outcomes but also draw attention to options unconsidered by others. This paper presents an agent-based simulation in which different kinds of information about choices are transmitted. This approach also provides a concrete model for certain aspects of hegemonic discourse . In standard Rational Choice where options are common knowledge, (...) all actors with the same preferences should make the same decisions. By contrast if information is transmitted socially, the concerns of a majority may reduce the ability of a minority to choose options appropriate to them even without any exercise of coercion or discrimination. (shrink)