This paper seeks to understand the importance of adopting an ethical framework based on values in the socio-ethical discussion on nanotechnology and generally on emerging technologies. In particular, within such framework it is introduced a distinction between two ideal types of science, defined on the basis of their different aims. Such distinction is considered to be a useful guide in the ethical debate on the technological development of our society, because it may help to understand what are the values of science and their relations with our values as members of the social community. My point is that a reflection on the values of science is needed to make scientists aware of their responsibilities as scientists in the society. Once scientists have understood their responsibilities as scientists they could be involved in a broader ethical reflection on their responsibilities as citizens. Technological development makes sense only if intended as an evolution of socio-technical systems and it is not possible to make an ethical evaluation of such evolution without having established what are our values and our idea of a common good. For these reasons nanotechnology should deal with our values, our idea of a common good, and our being responsible as citizens.
