those in favour of teaching NOS to science teachers, two main positions can be identified. One group concentrates on the intrinsic value that NOS has for the education of citizens (i.e. critical, autonomous, tolerant individuals who can live in society); these authors resort to what Rosalind Driver and her colleagues, in a text that is now classic, label democratic and cultural arguments: An understanding of the nature of science is necessary if people are to make sense of socioscientific issues and participate in the decision-making process. (...) [It] is necessary in order to appreciate science as a major element of contemporary culture. (Driver et al., 1996: 18-19) Therefore, supporters of this position argue that NOS would need to be introduced in science teacher education mainly because teachers are going to teach it in the classroom. I call this a curriculum perspective; it is well represented in the work of scholars within the English-speaking tradition, such as Derek Hodson (1988) and Michael Matthews (1994). The other group focuses on the participation of NOS in science teachers' professional development (Duschl, 1990; Izquierdo, 2000; Seroglou and Koumaras, 2001; Adriz-Bravo, 2006; Niaz, 2006) to a certain extent independently of curriculum considerations. NOS is then assumed to represent a second-order reflection on the content and methods of science that positively contributes to teachers' autonomy in the task of didactical transposition (i.e. the decision-making when transforming scientists' science into school science). I call this a meta-theoretical perspective. One of the main points on which there is