There is a widespread recognition of a 'crisis' in official scientific expe
rtise, related to the increase of 'uncertainty' and the loss of 'trust', an
d whose cure is believed to lie in 'participation'. I argue that the crisis
results from structural features of the globalising knowledge economy, and
the contradictory roles of governments, acting both as promoters of global
business enterprise and also as regulators on behalf of a sophisticated an
d suspicious public. I explain the crisis by substituting 'safety' for 'ris
k' as the operative concept, and also using 'paradox' as an explanatory too
l. I produce a closed-cycle paradox, analogous to the classic Catch-22, to
exhibit the contradictions in the situation. I discuss ways of resolving th
ese, which include the recognition of policy-critical ignorance and the ado
ption of the perspective of post-normal science. (C) 2001 Elsevier Science
B.V. All rights reserved.