The primary aim of this thesis is to examine some of the arguments that have been leveled against the idea that all value bearing entities are comparable. A secondary aim is to investigate some putative properties of the relation ‘better than', especially transitivity and vagueness. Also, some of the consequences of accepting incomparability are investigated, both with regards to other value theoretical issues, such as the implications for monadic value predicates, and with regards to more applied issues, such as the (...) comparison of risks. PAPER I is a critical examination of the so-called small-improvement argument for incomparability. It is demonstrated that the value structure this argument is able to distinguish is compatible not only with incomparability but also with a kind of evaluative indeterminacy that is distinct from incomparability. PAPER II argues that if the possibility of non-conventional value relations is granted it follows that some things that have value are neither good, bad, nor neutral. This counterintuitive conclusion is reached by combining two individually plausible analyses of value. PAPER III addresses the phenomenon of incomplete preferences. It is shown how it is possible to model incomplete preference orderings by means of probabilistic preferences, and how to reveal an agent's incomplete preference ordering within a behaviorist framework. PAPER IV examines another version of the small-improvement argument designed to establish the rationality of incomplete preferences. It is argued that while there might be reasons to believe each of the premises in this version, there is a conflict between these reasons. The conflict is such that we are not provided with a reason to believe the conjunction of the premises. And without support for the conjunction of the premises the small-improvement argument for incomparability fails. PAPER V defends the common sense claim that ‘better than' is transitive against the compelling counterexamples provided by Larry Temkin and Stuart Rachels. It is demonstrated that the contradiction that follows from accepting Temkin and Rachels' premises trades on the vagueness of ‘better than', and so does not warrant the rejection of transitivity, but rather the conclusion that ‘better than' is vague. PAPER VI applies the notions of incommensurability and incomparability to comparative risk analysis. It is argued that if risks are incommensurable, and thereby resistant to accurate comparisons in terms of severity, we cannot perform accurate and cost effective trade-offs between risks and their associated benefits. (shrink)