This article presents results of research analysing the views on the nature of science (NOS) among primary and secondary teachers working in state schools in two different cities in Colombia. Previous studies have reported that science teachers maintain 'eclectic' epistemological perspectives on science; in this article, we test if such hypothesis holds when teachers' ideas are 'anchored' in specific periods and topics of the philosophy of science. Thirty-five teachers attending a postgraduate teaching course with emphasis on the natural sciences at the Universidad del Norte (Barranquilla, Colombia) were assessed with the use of quantitative, descriptive and parametric research methods. The most important conclusion of this study is that teachers' expressed views on NOS maintain their epistemological eclecticism even when examined with more detail in relation to specific periods and topics of the philosophy of science. Such results can have negative implications for teachers' professionalisation, since fragile or labile conceptions of NOS could restrict the possibility of presenting a coherent view on science in the classroom.