Objectivity is made possible because experiment and logical consistency are the sole arbiters of truth - of no consequence is the scientist's mood or moral character, his political beliefs or nationality. or even his status in the world of science. On this last point, consider, for example, that Einstein was never taken too seriously when he (wrongly) set out to criticize quantum mechanics - this in spite of the fact that he was acknowledged as the greatest living physicist of the time.
Pervez Hoodbhoy Islam and Science: Religious Orthodoxy and the Battle for Rationality