Intra-mediary expertise: Trans-science and expert understanding of the public.

What is the role of experts and their expertise in the context of trans-science, in which issues that are raised in scientific terms cannot be answered by science alone? This article examines the discourses and practices around safety of low-dose exposure to radiation in the ongoing aftermath of the Fukushima Daiichi Nuclear Power Plant accident in Japan in 2011. Following the nuclear fallout, scientific experts and STS scholars in Japan debated what forms of science communication were adequate to address the situation. Ethnographic research and textual analysis of their debates show a shift in emphasis on the role of experts from cultivating 'public understanding of science' for the sake of science and policy to an 'expert understanding of the public' for the sake of the public and its diverse everyday concerns. Two forms of expertise are emerging: 'co-expertise' and 'intra-mediary expertise'. Both are parts of a transition from a paternalistic form of expertise to one that acknowledges the need to engage the public to address issues of scientific uncertainty. However, co-expertise ultimately upholds the existing political structures that shape risk governance, while intra-mediary expertise engages those often excluded from current structures of accountability. Discussion of the potentials and limitations of emerging forms of expertise in Japan show that epistemic justice is not enough. Civic justice that acknowledges diverse publics and their needs must be upheld in the uncertain sphere between science, politics, and everyday life.