The article summarizes the evolution of modern epistemology and relates it to sociology. It has two goals: 1) to pursue the way the formation of naturalistic and hermeneutic stream of epistemology resonates in the division of sociology into quantitative and qualitative; 2) to show consequences of the recent epistemological debate for this division of sociology. The concept of hermeneutical circle is used in the article to highlight that the knowledge of any social scientist is conditioned personally, historically and inter-subjectively. This can foster the respect towards the plurality of explanation and understanding processes. On the other hand, explanation and understanding are not to be put against each other. They represent two interdependent treats of human thinking.