Given the importance of the issue of scientific objectivity in our democratic societies and the significant development of citizen science, it is crucial to investigate how citizen science may either undermine or foster scientific objectivity. This paper identifies a variety of epistemic risks and benefits that participation of lay citizens in scientific inquiries may bring. It also discusses concrete actions and pending issues that should be addressed in order to foster objectivity in citizen science programs.

A central claim of Longino's contextual empiricism is that scientific inquiry, even when “properly conducted”, lacks the capacity to screen out the inºuence of contextual values on its results. I'll show first that Longino's attack against the epistemic integrity of science suffers from fatal empirical weak- nesses. Second I'll explain why Longino's practical proposition for suppressing biases in science, drawn from her contextual empiricism, is too demanding and, therefore, unable to serve its purpose. Finally, drawing on Bourdieu's sociological analysis of scientific communities, I'll sketch an alternative view of scientific practice reconciling a thoroughly social view of science (such as Longino's) with a defense of its epistemic integrity.