The Information Systems (IS) discipline is coined by a multiplicity of available conceptual modeling approaches. Thus, evaluation techniques have been developed in order to assess the appropriateness of a conceptual model in a given context. Up to now, however, both modeling and evaluation approaches lack a thorough epistemological foundation and discussion, leading to problems regarding the applicability of a certain modeling language in a given context on the one hand, and regarding the feasibility of certain evaluation approaches towards certain modeling questions on the other hand. We address the question of epistemology in evaluation research and therein argue that there is an immanent need for publishing epistemological underpinnings of evaluation approaches in order to assess their applicability in given modeling contexts. We present a basic discussion framework that allows for the analysis of epistemological implications of available evaluation approaches for conceptual modeling languages.