As the creation of large ontologies is a difficult and error-prone process, we think it is particularly relevant to develop new visual and interactive tools that support exploring ontologies as well as finding and resolving defects, such as undesired logical entailments. Exhibiting formal proofs for the undesired entailments can help in understanding how a defect happens, and linking the steps in the proof to the ontology can help in determining how the defect can be fixed. We present an interface that visualizes proofs and the corresponding ontology in form of side-by-side node-link diagrams. Building on linked brushing, users benefit from a strong interplay between these views, which allows for discovering and understanding defects. Besides traditional desktop workplaces, our interaction design also considers the use of touch input enabled by interactive displays. As part of an iterative design process, we developed an initial web-based prototype implementation and gathered feedback from an interview with domain experts. With this ongoing research and development, we aim to further investigate the potential and general utility of interactive visualizations for ontology engineering.