Realism has been the dominant approach in the philosophy of science for the last 20 years. Realist philosophy has also been widely employed across a range of social sciences. Unfortunately, these powerful intellectual currents have not reached the shores of nursing which appears trapped in a time-warped debate about ‘qualitative’ (constructivist) and ‘quantitative’ (positivist) approaches. This paper argues that both positivism and constructionism are seriously flawed as philosophies of social and natural science. This is in marked contrast with realism which is a philosophy of both the natural and social sciences. I therefore propose that realism should be adopted as a radically different new paradigm for a unified biopsychosocial nursing.