Sir

Harry Collins, in his thought-provoking Essay 'We cannot live by scepticism alone' (Nature 458, 30–31; 2009), calls for scientists to become 'moral leaders' and says that the 'values of science' can help us run our social and political lives. However, the argument raises at least two questions.

First, what does applying 'scientific values' mean in the real world, beyond observation, theorization, experimentation and 'open debate among those with experience'? If scientific values recognize plurality of perspective, freedom of expression and political negotiation beyond the alliances of the powerful, they would fit with the values of a liberal democracy. But the banner of 'scientific values' could equally be raised by an authoritarian technocracy, in which tacit and indigenous knowledge is marginalized. For example, some powerful people say that authoritarianism is what we need to tackle climate change.

Second, Collins recognizes that science is fallible and its findings 'do not lead straight to political conclusions'. So where does such uncertainty leave policy-making? How do Collins's scientific values help us in tackling difficult issues such as climate change or genetically modified crops?

Classifying different types of expertise is a worthy start, but we are still left with two further problems. First, who decides what expertise is legitimate in different situations? Second, how do we translate such expertise into action? In the rough and tumble of political processes, there is frequently no clear judge. Custom and power relationships usually decide whose expertise is heard. Without a theoretically based and politically supported manifesto to address these problems, a call for scientific values to 'run our lives' risks giving too much power to certain forms of knowledge.

See also: Let's not reignite an unproductive controversy Dialogue between the disciplines is thriving Widen the channels of communication with society