This article provides an insight into the philosophical assumptions underpinning evidence-based practice (EBP). Lois Goding and Keith Edwards believe that EBP has often been adopted within nursing, midwifery and health visiting without careful consideration of the nature of such evidence. This article explores the issues surrounding different research methodologies and methods, in particular the dichotomous relationships between positivism, constructivism and postmodernism. The authors believe that nursing involves complex, intangible human behaviour that demands an interpretative, holistic approach investigating perceptions rather than a reductionist approach.