The assumed impossibility of forming a widely accepted view of social work is explained on the one hand by the contesting nature of social work definitions and on the other by a loss of professional identity since the 1960s. The aim of the article is to elaborate a third explanation based on the hypothesis that social workers adhere to their differing interpretations of common social work themes. The argument for this article is designed from Foucault's idea of a "thematic realm which reveals a set of possible interpretations." To reach the aim, we address the question of why Bartlett, who explicitly adheres to an individual view of a common social work theme, emphasizes her specific interpretation of what she identifies as the social work focus. By generalizing the answer to this question, a hypothesis on the motives for defining social work in terms of individual views of a common social work theme is developed. It is argued that the lack of a widely accepted view of social work is a consequence of social work being defined by individual social workers based on ideas beyond their immediate conscious control. Suggestions are made on how to educate social workers to reflect on their unexamined motives for adhering to dissimilar interpretations of social work common themes.