This chapter explores the 'ethics of scientific assessment' for a society facing an unavoidable need to politically deal with scientific hypotheses that cannot be proven but that unquestionably matter for society. It argues that the occurrences of 'scientific perplexity' are not only a concern for the scientific community, but first and foremost a challenge for democracy, and this from the perspective that 'proper' scientific policy advice is an intrinsic quality of democracy rather than of science itself. A scientific hypothesis, in a common understanding, is a tentative explanation about a phenomenon or a set of phenomena observed in the natural or social world. S. Funtowicz and J. Ravetz provide with the necessary elements to understand and illustrate how to deal with the problem of scientific perplexity and 'the politics of hypothesis'. The case of Roundup or of thyroid cancer in Fukushima is in need of a democratisation of science as described by Philip Kitcher or Funtowicz and Ravetz.