The credibility of scientists is currently debated, especially regarding the credibility risks that may result from researchers' loss of autonomy vis-à-vis economic interests, activist rationale or political agendas. Such situations, where the credibility of scientists is put to the test in the eyes of society and their peers, raise a more general question: how do the scientists who are active in collectives situated in several social worlds build their credibility in the eyes of their colleagues? Do their activities reinforce, or weaken, the classical vectors of scientific credibility? Are new vectors of credibility emerging at the same time? The five articles in this special issue examine the contemporary reconfigurations of credibility based on four dimensions of transformation of the sciences: the rise of open data; science-industry relations; interdisciplinarity; and the public commitments of researchers. In this introductory article, we review the history of the notion of scientific credibility in Science & Technology Studies - as proposed by Bruno Latour and Steve Woolgar, then Steven Shapin and Thomas Gieryn - and the way it has been applied since then. Subsequently, we present the articles of the issue and draw transversal conclusions from them. We argue that, more than the advent of new vectors of scientific credibility, the articles show transformations at the margin, situational and contradictory.

The credibility of scientists is the subject of debate, which focuses on the risks of loss of credibility resulting from a loss of autonomy on the part of researchers vis-à-vis economic interests, militant logics or political agendas. These situations where scientific credibility is put to the test vis-à-vis society and the peer community raise a more general question: how do researchers involved in collectives positioned in several social worlds build their credibility with their colleagues? Do their activities reinforce, or weaken, the classic vectors of scientific credibility? At the same time, are new vectors of credibility emerging? The articles in this thematic dossier examine contemporary reconfigurations of credibility from the point of view of four areas of scientific transformation: data openness and banking; science-industry relations; interdisciplinarity; and researchers' public commitments. In this introductory article, we review the history of the notion of scientific credibility in Science & Technology Studies - as proposed by Bruno Latour and Steve Woolgar, then Steven Shapin and Thomas Gieryn - and the ways in which it has since been invested; then we present the five articles in the dossier and draw out their transversal contributions. We emphasize that, far more than the advent of new vectors of scientific credibility, these articles reveal transformations at the margins, situated and contradictory.

Toxicoepigenetics examines the health effects of environmental exposure associated with, or mediated by, changes in the epigenome. Despite high expectations, toxicoepigenomic data and methods have yet to become significantly utilized in chemical risk assessment. This article draws on a social science framework to highlight hitherto overlooked structural barriers to the incorporation of toxicoepigenetics in risk assessment and to propose ways forward. The present barriers stem not only from the lack of maturity of the field but also from differences in constraints and standards between the data produced by toxicoepigenetics and the regulatory science data that risk assessment processes require. Criteria and strategies that frame the validation of knowledge used for regulatory purposes limit the application of basic research in toxicoepigenetics toward risk assessment. First, the need in regulatory toxicology for standardized methods that form a consensus between regulatory agencies, basic research, and the industry conflicts with the wealth of heterogeneous data in toxicoepigenetics. Second, molecular epigenetic data do not readily translate into typical toxicological endpoints. Third, toxicoepigenetics investigates new forms of toxicity, in particular low-dose and long-term effects, that do not align well with the traditional framework of regulatory toxicology. We propose that increasing the usefulness of epigenetic data for risk assessment will require deliberate efforts on the part of the toxicoepigenetics community in 4 areas: fostering the understanding of epigenetics among risk assessors, developing knowledge infrastructure to demonstrate applicability, facilitating the normalization and exchange of data, and opening the field to other stakeholders.

Two distinct conceptions of personalized medicine in oncology accompany the development of epigenetic research: the study of molecular processes associated with tumor progression, which reinforces, in the medical arena, the molecularization program of genomic medicine; and the exploration of epigenetic mechanisms underlying the environmental causes of cancers, which brings, in the commercial sphere, scientific legitimacy to products and services whose marketing advocates each person's ability to protect themselves from cancer through an adapted lifestyle. Research into environmental epigenetics could open up a third avenue for personalized medicine, centered on an individualized approach to life courses.