Against the ideal of value-free science I argue that science is not––and cannot be––value-free and that relevant values are both cognitive and moral. I develop an argument by indicating various aspects of the value-ladenness of science. The recognition of the value-ladenness of science requires rethinking our understanding of the rationality and responsibility of science. Its rationality cannot be seen as merely instrumental––as it was seen by the ideal of value-free science––for this would result in limiting the autonomy of science and (...) reducing scientists to “minds to hire”. The scientific rationality must be seen as practical rationality which takes into account the full horizon of values. The scientific responsibility must also be broaden in scope and type. On this basis I draw three practical conclusions concerning the organization of research and training of young scientists, appealing to Plato’s claim that those most capable of healing are also those most capable of harming. (shrink)