You would need an impartial observer to make such an experiment. Perhaps some kind of machine that can measure such a force? Then do the experiment with two groups, etc. If you do not have that, then there is absolutely no functional difference between such a "force" and faith/placebo. Unless of course if such a machine doesn't exist. So the problem isn't with science. It's that we don't yet have machines that can measure everything. When we understand consciousness better, we'll do experiments with that as well. Or would you prefer we all went with faith instead? That isn't science.
I don't know why you say that James Randi is not a man of science. Yes, I suspect that you do, as do I, perceive him as kind of cynical and dismissive of paranormal arguments. But then again, so would you be if you had been dealing with the world's biggest crazy nutty self-deluded crackpots for the last 50 years. And it doesn't really surprise me that no one won the prize. After all, it would be about the most important profound scientific discovery of recent times if it ever happened.
I tell them to turn to the study of mathematics, for it is only there that they might escape the lusts of the flesh. -- Thomas Mann, "The Magic Mountain"