Based on the argument that ontology precedes epistemology and that method is not necessarily the route that leads to knowledge, it is asked why psychology has embraced a methodologism and a narrow epistemology when debating questions about psychological knowledge, ways for achieving knowledge, and the meanings of knowledge more generally. Some critics have labeled mainstream psychology as positivist; yet, this assessment is not entirely accurate if one takes the history and goals of positivism into account. An important task of theoretical psychology remains to make these naïve empiricist commitments explicit, in their consequences for psychological knowledge. Concepts such as variables, causality, operationism, and explanation are challenged. Critical ideas such as that ontology and epistemology are in practice intertwined, how a commitment to a specific conceptualization of the subject matter implies specific methodological commitments and vice versa, as well as the roles of relevance, temporality, authority, society, and culture in knowledge-making are discussed. A methodological theory of truth is challenged. It is argued that psychologists do not provide scientific explanations, but rather theory-dependent interpretations.