Nursing knowledge stems from a dynamic interplay between population-based scientific knowledge (the general) and specific clinical cases (the particular). We compared the 'cascade model of knowledge translation', also known as 'classical biomedical model' in clinical practice (in which knowledge gained at population level may be applied directly to a specific clinical context), with an emergentist model of knowledge translation. The structure and dynamics of nursing knowledge are outlined, adopting the distinction between epistemic and non-epistemic values. Then, a (moderately) emergentist approach to nursing knowledge is proposed, based on the assumption of a two-way flow from the general to the particular and vice versa. The case of the 'placebo effect' is analysed as an example of emergentist knowledge. The placebo effect is usually considered difficult to be explained within the classical biomedical model, and we underscore its importance in shaping nursing knowledge. In fact, nurses are primarily responsible for administering placebo in the clinical setting and have an essential role in promoting the placebo effect and reducing the nocebo effect. The beliefs responsible for the placebo effect are as follows: (1) interactive, because they depend on the relationship between patients and health care professionals; (2) situated, because they occur in a given clinical context related to certain rituals; and (3) grounded on higher order beliefs concerning what an individual thinks about the beliefs of others. It is essential to know the clinical context and to understand other people's beliefs to make sense of the placebo effect. The placebo effect only works when the (higher order) beliefs of doctors, nurses and patients interact in a given setting. Finally, we argue for a close relationship between placebo effect and nursing knowledge. [ABSTRACT FROM AUTHOR]