The aim of this study is to attain a better understanding of the relationship between competing or complementary scientific explanatory claims. First, six different ways of approaching explanatory claims are briefly described and found, in part, to be unsatisfactory. It is argued that they should be supplemented by an analysis of underlying and sometimes partly unacknowledged causal presuppositions. This approach could be termed a causal analytical investigation, and in order to demonstrate its potential, it is applied to a concrete example: research into dental anxiety. The analysis shows that seemingly competing or complementary explanatory claims here neither compete with nor complement each other; instead, the analysis demonstrates that they explain different things. We then broaden the picture by discussing the relationship between aetiology and treatment. Finally we argue in favour of the general applicability of the approach and its relevance to science in general and to science-based practice.