The British Journal for the Philosophy of Science - current issue

De Finetti, Countable Additivity, Consistency and Coherence

Howson, C. — 2008-03-26

Many people believe that there is a Dutch Book argument establishing that the principle of countable additivity is a condition of coherence. De Finetti himself did not, but for reasons that are at first sight perplexing. I show that he rejected countable additivity, and hence the Dutch Book argument for it, because countable additivity conflicted with intuitive principles about the scope of authentic consistency constraints. These he often claimed were logical in nature, but he never attempted to relate this idea to deductive logic and its own concept of consistency. This I do, showing that at one level the definitions of deductive and probabilistic consistency are identical, differing only in the nature of the constraints imposed. In the probabilistic case I believe that R.T. Cox's ‘scale-free’ axioms for subjective probability are the most suitable candidates.

1 Introduction

2 Coherence and Consistency

3 The Infinite Fair Lottery

4 The Puzzle Resolved—But Replaced by Another

5 Countable Additivity, Conglomerability and Dutch Books

6 The Probability Axioms and Cox's Theorem

7 Truth and Probability

8 Conclusion: ‘Logical Omniscience’

Varieties of Population Structure and the Levels of Selection

Godfrey-Smith, P. — 2008-03-26

Group-structured populations, of the kind prominent in discussions of multilevel selection, are contrasted with ‘neighbor-structured’ populations. I argue that it is a necessary condition on multilevel description of a selection process that there should be a nonarbitrary division of the population into equivalence classes (or an approximation to this situation). The discussion is focused via comparisons between two famous problem cases involving group structure (altruism and heterozygote advantage) and two neighbor-structured cases that resemble them. Conclusions are also drawn about the role of correlated interaction in the evolution of altruism.

1 Introduction

2 Two Kinds of Population Structure

3 Objections and Replies

4 Particles on a Line

5 Conclusion

Appendix: Neighborhoods and Selection

The Somatic Marker Hypotheses, and What the Iowa Gambling Task Does and Does not Show

Colombetti, G. — 2008-03-26

Damasio's somatic marker hypothesis (SMH) is a prominent neuroscientific hypothesis about the mechanisms implementing decision-making. This paper argues that, since its inception, the SMH has not been clearly formulated. It is possible to identify at least two different hypotheses, which make different predictions: SMH-G, which claims that somatic states generally implement preferences and are needed to make a decision; and SMH-S, which specifically claims that somatic states assist decision-making by anticipating the long-term outcomes of available options. This paper also argues that neither hypothesis is adequately supported empirically; the task originally proposed to test SMH is not a good test for SMH-S, and its results do not support SMH-G either. In addition, it is not clear how SMH-G could be empirically invalidated, given its general formulation. Suggestions are made that could help provide evidence for SMH-S, and make SMH-G more specific.

1 Introduction

2 Two Hypotheses: Somatic Markers as Embodied Preferences, and as a Source of Farsightedness

3 Lack of Evidence for Somatic Farsightedness

4 Does Making Decisions Require Somatic Markers, and can it be Shown in the Laboratory?

5 Conclusion

The One World, One Science Argument

Kukla, A. — 2008-03-26

The one world, one science argument (so named by Rescher) is advanced by Carl Sagan and others to support the thesis that we will be able to learn to converse with intelligent extraterrestrials if and when we encounter them. The prima facie obstacle to extraterrestrial communication is that the aliens’ culture and geography are bound to be so different from ours that we would find it extremely difficult, if not practically impossible, to find a common topic on which we can both converse. Sagan's rebuttal is that we will share mathematics and the laws of physics, these being the same for all intelligent beings regardless of local cultural and geographical variations. I show that this argument fails even if its contentious assumptions about science and the world are granted—that is to say, it fails on uncontentious grounds.

1 OWOS

2 OWOS and Social Constructivism

3 OWOS and Conceptual Relativism

4 OWOS and the Selection Problem

5 The Fundamental Laws Solution

6 The Mathematics Solution

7 The Radio Solution

8 The Common Conditions Solution

9 The Intractability of the Selection Problem

10 The Superfluity of OWOS

What Evidence Do You Have?

Neta, R. — 2008-03-26

Your evidence constrains your rational degrees of confidence both locally and globally. On the one hand, particular bits of evidence can boost or diminish your rational degree of confidence in various hypotheses, relative to your background information. On the other hand, epistemic rationality requires that, for any hypothesis h, your confidence in h is proportional to the support that h receives from your total evidence. Why is it that your evidence has these two epistemic powers? I argue that various proposed accounts of what it is for something to be an element of your evidence set cannot answer this question. I then propose an alternative account of what it is for something to be an element of your evidence set.

1 Introduction

2 The elements of one's evidence set are propositions

3 Which kinds of propositions are in one's evidence set?

3.1 Doxastic accounts of evidence

3.2 Non-doxastic accounts of evidence

4 Elaborating and defending the LIE