受到專業建制化的思潮影響，精神醫療社會工作常將後實證主義當作是學術研究與臨床實務的金科玉律。但隨著社會環境日趨複雜多變，加上知識體系的多元蓬勃發展，本研究認為，精神醫療社會工作員應培養「知識論思辨能力」 ─即分析、批判及整合多元知識的能力，才能善盡專業職責，並取得專業主體性。知識論是從典範的層次來討論「知識的理論」，其內涵包括知識的本質、取得、應用與限制，目前西方國家的文獻多將知識論典範概略地區分為後實證主義、建構主義與批判理論，而全人取向則源自於華人文化。為具體示範如何應用知識論的思辨能力，本研究以精神醫療社會工作員協助憂鬱個案為討論脈絡，從上述四個典範來進行相關文獻的回顧後，分別從憂鬱本質、社工角色、理論觀點、實務取向，以及社工倫理原則來進行知識論分析。結論指出：上述四套知識論典範皆與精神醫療社會工作實務密切相關，社工員要多方學習知識論視角，不應偏廢或獨厚；知識論思辨能力也應成為社會工作教育的目標，如此社會工作才能在專業社群中取得獨特位置。

Following the movement toward professional institutionalization, social work in the contemporary era tends to uncritically endorse post-positivism in research and practice with the attempt to gain societal recognition as real professionals. However, in the context of a rapidly and enormously changing society, along with an increasingly diversified practical knowledge, the author of this article argues for the building of the competence of social workers for epistemological thinking—an ability to analyze, critique, and synthesize knowledge—as essential to fully serve the mission of the profession, and, more importantly, to establish a professional distinctive space. An epistemological paradigm contains a set of statements with respect to the nature, assumptions, applications, and limitations of knowledge. Four epistemological paradigms have been delineated in the existing literature including positivism, post-positivism, constructivism, and critical theory. In addition, the holistic approach, which is rooted in Chinese philosophy, has been a widely practiced paradigm in the Chinese context. To demonstrate the competence for epistemological thinking, this article used these four paradigms to synthesize and structure the literature in relation to depression, a significant issue that has been extensively addressed by psychiatric social workers. As a summary table is made to situate knowledge within the four paradigms, it becomes evident that knowledge developed in accordance with the four epistemological paradigms is relevant for, and should be integrated into, social work practice. As such, this article suggests that rather than being sorely attached to a particular epistemological paradigm, social workers need to develop a comprehensive familiarity with the various epistemological approaches in order to be responsive to the clients’ wide range of needs. By utilizing the epistemological analysis model expounded in this article, it is hoped that epistemological thinking will be incorporated into social work education and training.