@durakken: I just recently heard of that event. One event doesn't refute or prove any claim. But the lack of concrete evidence from centuries of trying can't be ignored.
The problem is that you are looking at that as one event... It is just the test with the most set conditions.
People say that absence of evidence is not evidence of absence, but that is wrong. If someone makes a claim and it fails to produce evidence supporting it, that is showing that whatever their is, they are lacking the evidence to back it up which is evidence that that evidence does not exist. You would expect that the evidence doesn't exist if the claim is wrong.
We're talking millenia after millenia of people making claims and never once producing evidence when people could go check. That is evidence that their claim is wrong. Houdini's seance is just the longest running test of a claim going that has continued to show that all disembodied humans as ghosts is indeed very likely not true, but as I have said in other places, the phenomena that is called ghosts is real. There's no question there. It's just a matter of what caused it in this or that particular scenario.