•  137
    Beyond Uncertainty: Reasoning with Unknown Possibilities
    with H. Orri Stefánsson
    Cambridge University Press. 2021.
    The main aim of this book is to introduce the topic of limited awareness, and changes in awareness, to those interested in the philosophy of decision-making and uncertain reasoning. (This is for the series Elements of Decision Theory published by Cambridge University Press and edited by Martin Peterson)
  •  147
    What Should We Agree on about the Repugnant Conclusion?
    with Stéphane Zuber, Nikhil Venkatesh, Torbjörn Tännsjö, Christian Tarsney, H. Orri Stefánsson, Dean Spears, Jeff Sebo, Marcus Pivato, Toby Ord, Yew-Kwang Ng, Michal Masny, William MacAskill, Nicholas Lawson, Kevin Kuruc, Michelle Hutchinson, Johan E. Gustafsson, Hilary Greaves, Lisa Forsberg, Marc Fleurbaey, Diane Coffey, Susumu Cato, Clinton Castro, Tim Campbell, Mark Budolfson, John Broome, Alexander Berger, Nick Beckstead, and Geir B. Asheim
    Utilitas 1-5. forthcoming.
    The Repugnant Conclusion served an important purpose in catalyzing and inspiring the pioneering stage of population ethics research. We believe, however, that the Repugnant Conclusion now receives too much focus. Avoiding the Repugnant Conclusion should no longer be the central goal driving population ethics research, despite its importance to the fundamental accomplishments of the existing literature.
  •  248
    Modelling the Moral Dimension of Decisions
    Noûs 44 (3): 503-529. 2010.
    In this paper we explore the connections between ethics and decision theory. In particular, we consider the question of whether decision theory carries with it a bias towards consequentialist ethical theories. We argue that there are plausible versions of the other ethical theories that can be accommodated by “standard” decision theory, but there are also variations of these ethical theories that are less easily accommodated. So while “standard” decision theory is not exclusively consequentialis…Read more
  •  245
    Should subjective probabilities be sharp?
    Episteme 11 (3): 277-289. 2014.
    There has been much recent interest in imprecise probabilities, models of belief that allow unsharp or fuzzy credence. There have also been some influential criticisms of this position. Here we argue, chiefly against Elga, that subjective probabilities need not be sharp. The key question is whether the imprecise probabilist can make reasonable sequences of decisions. We argue that she can. We outline Elga's argument and clarify the assumptions he makes and the principles of rationality he is imp…Read more
  •  373
    Belief Revision for Growing Awareness
    with H. Orri Stefánsson
    Mind. forthcoming.
    The Bayesian maxim for rational learning could be described as conservative change from one probabilistic belief or credence function to another in response to newinformation. Roughly: ‘Hold fixed any credences that are not directly affected by the learning experience.’ This is precisely articulated for the case when we learn that some proposition that we had previously entertained is indeed true (the rule of conditionalisation). But can this conservative-change maxim be extended to revisi…Read more
  •  35
    Climate Science, The Philosophy of
    with Richard Bradley, Roman Frigg, Erica Thompson, and Charlotte Werndl
    Internet Encyclopedia of Philosophy. 2020.
    The Philosophy of Climate Science Climate change is one of the defining challenges of the 21st century. But what is climate change, how do we know about it, and how should we react to it? This article summarizes the main conceptual issues and questions in the foundations of climate science, as well as of the … Continue reading Climate Science, The Philosophy of →
  •  139
    In this paper, we develop a novel response to counterfactual scepticism, the thesis that most ordinary counterfactual claims are false. In the process we aim to shed light on the relationship between debates in the philosophy of science and debates concerning the semantics and pragmatics of counterfactuals. We argue that science is concerned with many domains of inquiry, each with its own characteristic entities and regularities; moreover, statements of scientific law often include an implicit c…Read more
  •  13
    Towards the end of Decision Theory with a Human Face, Richard Bradley discusses various ways a rational yet human agent, who, due to lack of evidence, is unable to make some fine-grained credibility judgments, may nonetheless make systematic decisions. One proposal is that such an agent can simply “reach judgments” on the fly, as needed for decision making. In effect, she can adopt a precise probability function to serve as proxy for her imprecise credences at the point of decision, and then sub…Read more
  •  66
    Climate models, confirmation and calibration
    British Journal for the Philosophy of Science 64 (3): 609-635. 2013.
    We argue that concerns about double-counting -- using the same evidence both to calibrate or tune climate models and also to confirm or verify that the models are adequate --deserve more careful scrutiny in climate modelling circles. It is widely held that double-counting is bad and that separate data must be used for calibration and confirmation. We show that this is far from obviously true, and that climate scientists may be confusing their targets. Our analysis turns on a Bayesian/relative-li…Read more
  •  83
    There are at least two plausible generalisations of subjective expected utility (SEU) theory: cumulative prospect theory (which relaxes the independence axiom) and Levi’s decision theory (which relaxes at least ordering). These theories call for a re-assessment of the minimal requirements of rational choice. Here, I consider how an analysis of sequential decision making contributes to this assessment. I criticise Hammond’s (Economica 44(176):337–350, 1977; Econ Philos 4:292–297, 1988a; Risk, dec…Read more
  •  35
    Assessing ethical trade-offs in ecological field studies
    with Kirsten M. Parris, Sarah C. McCall, Michael A. McCarthy, Ben A. Minteer, Sarah Bekessy, and Fabien Medvecky
    Journal of Applied Ecology 47 (1): 227-234. 2010.
    Summary 1. Ecologists and conservation biologists consider many issues when designing a field study, such as the expected value of the data, the interests of the study species, the welfare of individual organisms and the cost of the project. These different issues or values often conflict; however, neither animal ethics nor environmental ethics provides practical guidance on how to assess trade-offs between them. 2. We developed a decision framework for considering trade-offs between values in e…Read more
  •  257
    In the biomedical context, policy makers face a large amount of potentially discordant evidence from different sources. This prompts the question of how this evidence should be aggregated in the interests of best-informed policy recommendations. The starting point of our discussion is Hunter and Williams’ recent work on an automated aggregation method for medical evidence. Our negative claim is that it is far from clear what the relevant criteria for evaluating an evidence aggregator of this sor…Read more
  •  47
    The Diversity of Model Tuning Practices in Climate Science
    Philosophy of Science 83 (5): 113-114. 2016.
    Many examples of calibration in climate science raise no alarms regarding model reliability. We examine one example and show that, in employing Classical Hypothesis-testing, it involves calibrating a base model against data that is also used to confirm the model. This is counter to the "intuitive position". We argue, however, that aspects of the intuitive position are upheld by some methods, in particular, the general Cross-validation method. How Cross-validation relates to other prominent Class…Read more
  •  21
    Review of Husain Sarkar, Group Rationality in Scientific Research (review)
    Notre Dame Philosophical Reviews 2007 (10). 2007.
  •  90
    I focus my discussion on the well-known Ellsberg paradox. I find good normative reasons for incorporating non-precise belief, as represented by sets of probabilities, in an Ellsberg decision model. This amounts to forgoing the completeness axiom of expected utility theory. Provided that probability sets are interpreted as genuinely indeterminate belief, such a model can moreover make the “Ellsberg choices” rationally permissible. Without some further element to the story, however, the model does…Read more
  •  60
    Daniel steel philosophy and the precautionary principle: Science, evidence, and environmental policy
    with Camilla Colombo
    British Journal for the Philosophy of Science 67 (4): 1195-1200. 2016.
  •  15
    Review of Preference and Information (review)
    Economics and Philosophy 25 (2): 236-242. 2009.
  •  67
    Model tuning in engineering: uncovering the logic
    Journal of Strain Analysis for Engineering Design 51 (1): 63-71. 2015.
    In engineering, as in other scientific fields, researchers seek to confirm their models with real-world data. It is common practice to assess models in terms of the distance between the model outputs and the corresponding experimental observations. An important question that arises is whether the model should then be ‘tuned’, in the sense of estimating the values of free parameters to get a better fit with the data, and furthermore whether the tuned model can be confirmed with the same data used…Read more
  •  228
    This paper considers a puzzling conflict between two positions that are each compelling: it is irrational for an agent to pay to avoid `free' evidence before making a decision, and rational agents may have imprecise beliefs and/or desires. Indeed, we show that Good's theorem concerning the invariable choice-worthiness of free evidence does not generalise to the imprecise realm, given the plausible existing decision theories for handling imprecision. A key ingredient in the analysis, and a potent…Read more
  •  62
    This paper considers a key point of contention between classical and Bayesian statistics that is brought to the fore when examining so-called ‘persistent experimenters’—the issue of stopping rules, or more accurately, outcome spaces, and their influence on statistical analysis. First, a working definition of classical and Bayesian statistical tests is given, which makes clear that (1) once an experimental outcome is recorded, other possible outcomes matter only for classical inference, and (2) f…Read more
  •  686
    Environmental Ethics and Decision Theory: Fellow Travellers or Bitter Enemies?
    In Kevin deLaplante, Bryson Brown & Kent Peacock (eds.), Philosophy of Ecology, Elsevier Science Publishers. pp. 285--300. 2011.
    On the face of it, ethics and decision theory give quite different advice about what the best course of action is in a given situation. In this paper we examine this alleged conflict in the realm of environmental decision-making. We focus on a couple of places where ethics and decision theory might be thought to be offering conflicting advice: environmental triage and carbon trading. We argue that the conflict can be seen as conflicts about other things (like appropriate temporal scales for valu…Read more
  •  51
    Testimony as Evidence: More Problems for Linear Pooling (review)
    Journal of Philosophical Logic 41 (6): 983-999. 2012.
    This paper considers a special case of belief updating—when an agent learns testimonial data, or in other words, the beliefs of others on some issue. The interest in this case is twofold: (1) the linear averaging method for updating on testimony is somewhat popular in epistemology circles, and it is important to assess its normative acceptability, and (2) this facilitates a more general investigation of what it means/requires for an updating method to have a suitable Bayesian representation (tak…Read more
  •  222
    This article argues that common intuitions regarding (a) the specialness of ‘use-novel’ data for confirmation and (b) that this specialness implies the ‘no-double-counting rule’, which says that data used in ‘constructing’ (calibrating) a model cannot also play a role in confirming the model’s predictions, are too crude. The intuitions in question are pertinent in all the sciences, but we appeal to a climate science case study to illustrate what is at stake. Our strategy is to analyse the intuit…Read more
  •  199
    Making Climate Decisions
    with Richard Bradley
    Philosophy Compass 10 (11): 799-810. 2015.
    Many fine-grained decisions concerning climate change involve significant, even severe, uncertainty. Here, we focus on modelling the decisions of single agents, whether individual persons or groups perceived as corporate entities. We offer a taxonomy of the sources and kinds of uncertainty that arise in framing these decision problems, as well as strategies for making a choice in spite of uncertainty. The aim is to facilitate a more transparent and structured treatment of uncertainty in climate …Read more
  •  45
    Right decisions or happy decision-makers?
    with Helen M. Regan, Mark Colyvan, and Mark A. Burgman
    Social Epistemology 21 (4). 2007.
    Group decisions raise a number of substantial philosophical and methodological issues. We focus on the goal of the group decision exercise itself. We ask: What should be counted as a good group decision-making result? The right decision might not be accessible to, or please, any of the group members. Conversely, a popular decision can fail to be the correct decision. In this paper we discuss what it means for a decision to be "right" and what components are required in a decision process to prod…Read more
  •  309
    Climate Models, Calibration, and Confirmation
    British Journal for the Philosophy of Science 64 (3): 609-635. 2013.
    We argue that concerns about double-counting—using the same evidence both to calibrate or tune climate models and also to confirm or verify that the models are adequate—deserve more careful scrutiny in climate modelling circles. It is widely held that double-counting is bad and that separate data must be used for calibration and confirmation. We show that this is far from obviously true, and that climate scientists may be confusing their targets. Our analysis turns on a Bayesian/relative-likelih…Read more