Abstract

. Consistent valuation and societal prioritization of risks presupposes comparability among risks, that is, in order to rank risks in order of severity, and allocate risk preventative resources accordingly, we must be able to determine whether one risk is better or worse than another, and by how much. It is often claimed, however, that some risks are not amenable to this kind of comparison because they are incommensurable, which roughly means that they are not comparable with respect to a common cardinal measure. The aim of this thesis is to i) consider what it means to say that two risks are incommensurable, ii) explore if incomparability - comparison failure with respect to a common ordinal scale - ever occurs, and how to model it if it does. Essay I is a critical examination of the most prominent argument for incomparability, the so-called small improvement argument. It is argued that the argument fails because it conflates incomparability and a kind of evaluative indeterminacy. Essay II outlines so-called margin of error principles for comparative value judgements. They are based on the idea that if a proposition concerning the value relation between two value-bearing options is true, but there are sufficiently similar cases in which it is false, it is not available to be known. The usefulness of these principles is demonstrated by utilizing them in an epistemological case against SIA. Essay III presents a novel account of incomplete preference orderings which acknowledges that incomparability can vary in degrees. This is achieved by means of a probabilistic analysis of preferences.