I think Bob's point has to be modified in certain ways, in that I think that science has the means to eventually correct its biases and mistakes over time. It is a human enterprise, subject to peer pressures and what not, but eventually it has the ability to snap out of its biases. Take, for example, the behaviorist phenomenon in psychology. I remember when I was an undergraduate that the entire psychology department at ASU was one big rat lab. Eventually this broke down, and now this period of the history of psychology is made fun of. But you would have been made fun of in those days if you thought behaviorism wasn't the wave of the future. Sometimes science gets out of a rut simply because the major figures keeping it in that rut die off.
In short, I would say that science has ways of moving in the direction of objectivity, but the wheels of the science gods may move more slowly than most people realize. Hence a strong apparent consensus in the scientific community may represent nothing more than a passing phase, not a guarantee that science has reached genuine certainty.
I'm not saying Bob would deny this. I do think what you have to say that science, as a intersubjective human enterprise, moves in the direction of objectivity, though it never achieves complete objectivity.