The days are gone, if they ever really existed, when it was possible to maintain that science progressively accumulates permanent, objective knowledge of nature, detached from social influence. Kitcher opens a recent book by referring to that view as "Legend," meaning to indicate that it is both bygone and groundless. What is still present and contested, however, is the question of the reach of social factors in the production of scientific knowledge. Is scientific knowledge wholly constructed out of social factors, or is there some part which is shaped by nonsocial rational or epistemic elements?