From the VS Science archives, produced in cooperation with MICA, the Meta Institute for Computational Astrophysics:Tom Levensontalks with Science Historian Naomi Oreskes, author of "Merchants of Doubt, How a Handful of Scientists Obscured the Truth on Issues from Tobacco to Global Warming," about Big Tobacco, climate science, the establishment of scientific consensus and the role and character of scientific dissent. Follow @TomLevenson