Evidential Uniqueness in Classical and Formal Cognitive Theory

The evidential uniqueness thesis claims roughly that, in the light of a certain body of evidence E, at most one doxastic attitude - belief, disbelief, or suspension of belief - toward any particular proposition may be rationally adopted by subjects. This paper discusses the relevance of the thesis in both classical (non-formal) as well as formal epistemological research traditions. It goes on to investigate the plausibility of the thesis and the considerations on which its initial attractiveness rests. It is argued that all the considerations in favor of the thesis that can be found in the literature are unconvincing. However, a thus far overlooked argument is presented that is able to motivate the thesis - at least to a certain extent.