My original comment was a reply to Mitchell Porter, who suggested that parapsychology would somehow receive support from the Matrix hypothesis. I replied by saying that this would not be true, or at least not clearly, if that hypothesis is understood as a claim about the ultimate nature of reality.
To take another example, suppose someone argued Berkeleyan idealists should be more open to psychic phenomena, since we are all ideas in the mind of God. I would reply that this is not so, since the fact that the world is ultimately made of mind has in itself no implications about whether certain kinds of mental phenomena take place within that world.
The ability of certain collections of atoms to communicate large amounts of information to other collections of atoms over vast distances without there being any detectable emissions is an incredibly complex power. Complex entities are a priori improbable compared to simple entities. You need some kind of creation mechanism to make them probable... with biological systems we have evolution, with pocket watches and jet planes you have human inventors. If you accept a metaphysical hypothesis that involves an intelligence creating the universe-- programmers or God-- you have a mechanism for making complex entities probable. That is why the Matrix hypothesis makes psychic phenomena more likely
Parapsychologists are constantly protesting that they are playing by all the standard scientific rules, and yet their results are being ignored - that they are unfairly being held to higher standards than everyone else. I'm willing to believe that. It just means that the standard statistical methods of science are so weak and flawed as to permit a field of study to sustain itself in the complete absence of any subject matter.
— Eliezer Yudkowsky, Frequentist Statistics are Frequently Subjective
Imagine if, way back at the start of the scientific enterprise, someone had said, "What we really need is a control group for science - people who will behave exactly like scientists, doing experiments, publishing journals, and so on, but whose field of study is completely empty: one in which the null hypothesis is always true.
"That way, we'll be able to gauge the effect of publication bias, experimental error, misuse of statistics, data fraud, and so on, which will help us understand how serious such problems are in the real scientific literature."
Isn't that a great idea?
By an accident of historical chance, we actually have exactly such a control group, namely parapsychologists: people who study extra-sensory perception, telepathy, precognition, and so on.
There's no particular reason to think parapsychologists are doing anything other than what scientists would do; their experiments are similar to those of scientists, they use statistics in similar ways, and there's no reason to think they falsify data any more than any other group. Yet despite the fact that their null hypotheses are always true, parapsychologists get positive results.
This is disturbing, and must lead us to wonder how many positive results in real science are actually wrong.
The point of all this is not to mock parapsychology for the sake of it, but rather to emphasise that parapsychology is useful as a control group for science. Scientists should aim to improve their procedures to the point where, if the control group used these same procedures, they would get an acceptably low level of positive results. That this is not yet the case indicates the need for more stringent scientific procedures.
Acknowledgements
The idea for this mini-essay and many of its actual points were suggested by (or stolen from) Eliezer Yudkowsky's Frequentist Statistics are Frequently Subjective, though the idea might have originated with Michael Vassar.
This was originally published at a different location on the web, but was moved here for bandwidth reasons at Eliezer's suggestion.
Comments / criticisms
A discussion on Hacker News contained one very astute criticism: that some things which may once have been considered part of parapsychology actually turned out to be real, though with perfectly sensible, physical causes. Still, I think this is unlikely for the more exotic subjects like telepathy, precognition, et cetera.