When do probability distribution functions (PDFs) about future climate misrepresent uncertainty? How can we recognise when such misrepresentation occurs and thus avoid it in reasoning about or communicating our uncertainty? And when we should not use a PDF, what should we do instead? In this paper we address these three questions. We start by providing a classification of types of uncertainty and using this classification to illustrate when PDFs misrepresent our uncertainty in a way that may adversely affect decisions. We (...) then discuss when it is reasonable and appropriate to use a PDF to reason about or communicate uncertainty about climate. We consider two perspectives on this issue. On one, which we argue is preferable, available theory and evidence in climate science basically excludes using PDFs to represent our uncertainty. On the other, PDFs can legitimately be provided when resting on appropriate expert judgement and recognition of associated risks. Once we have specified the border between appropriate and inappropriate uses of PDFs, we explore alternatives to their use. We briefly describe two formal alternatives, namely imprecise probabilities and possibilistic distribution functions, as well as informal possibilistic alternatives. We suggest that the possibilistic alternatives are preferable. -/- . (shrink)

Climate change adaptation is largely a local matter, and adaptation planning can benefit from local climate change projections. Such projections are typically generated by accepting climate model outputs in a relatively uncritical way. We argue, based on the IPCC’s treatment of model outputs from the CMIP5 ensemble, that this approach is unwarranted and that subjective expert judgment should play a central role in the provision of local climate change projections intended to support decision-making.

This is the second of three parts of an introduction to the philosophy of climate science. In this second part about modelling climate change, the topics of climate modelling, confirmation of climate models, the limits of climate projections, uncertainty and finally model ensembles will be discussed.

This is the first of three parts of an introduction to the philosophy of climate science. In this first part about observing climate change, the topics of definitions of climate and climate change, data sets and data models, detection of climate change, and attribution of climate change will be discussed.

An important application of cognitive architectures is to provide human performance models that capture psychological mechanisms in a form that can be “programmed” to predict task performance of human–machine system designs. Although many aspects of human performance have been successfully modeled in this approach, accounting for multitalker speech task performance is a novel problem. This article presents a model for performance in a two-talker task that incorporates concepts from psychoacoustics, in particular, masking effects and stream formation.

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 →.

Simply stated, Pragmatic Invariantism is the view that the practical interests of a person can influence whether that person’s true belief constitutes knowledge. My primary objective in this article is to show that Pragmatic Invariantism entails external world skepticism. Toward this end, I’ll first introduce a basic version of Pragmatic Invariantism (PI). Then I’ll introduce a sample skeptical hypothesis (SK) to the framework. From this I will show that it is extremely important that the phenomenally equivalent skeptical scenarios generated by (...) SK are actually false. We’ll then see that by combining PI and SK, the effect will be to place extremelyhigh demands upon evidence for ~SK. It will finally be observed that, while we may have good evidence for ~SK, we do not have extremely strong evidence sufficient for establishing ~SK. This supports my conclusion that any standard version of Pragmatic Invariantism ultimately entails external world skepticism. If successful, my conclusion will critically undermine the current view that Pragmatic Invariantism is actually a skeptically resistant position. (shrink)