This idea that we are so sure of everything is pervasive. The kind of people who like science are often the kind of people who crave certainty. And so for them science becomes like a religion, it provides them with a sense of certainty. Consistency. So when they rally against stories like this what they are really doing is reaffirming their own faith in an orderly universe, reaffirming their own faith in their scientific religion. It serves an emotional need. Which is why, paradoxically, their arguments are not alterable through logic.

If you go read what the real experts in a field have to say about the state of knowledge, they are often incredibly humble. They state that there is so much that they do not know. That are so many things that could be wrong. That there are even bigger pictures just beyond their grasp.

Now these reactionless thruster concepts don't look to be doing too well. But I for one am not particularly convinced that mach 's principle is so stupid.