[robinh]

So... I know next to nothing about parapsychology itself, but have seen a lot of the drama around it, and I just have to ask: is it not intellectually dishonest to call something the 'control group of science' when their results overwhelmingly support the hypothesis? I have a hard time seeing how this is different from any other form of science denialism. "We don't like the results because they clash with our preconceived notions of how the universe works so we made up this thing to ignore your evidence"? That's hardly a valid complaint. Basically, on what grounds can people claim one field to be nonsense (e.g. calling parapsychology the control group of science) but not others? Can someone explain this to me?

[jarrett]

It's a valid question. The article takes the following premise: Parapsychology gets positive results following the scientific method as defined by prevailing norms in the scientific community. So why can't we draw the conclusion that parapsychology is as legitimate as other branches of science? What is to separate it?

I would offer a pseudo-Bayesian[1] answer to that question. Parapsychology aims to prove hypotheses that lacks theoretical foundations. Our current understanding of physics and biology weigh strongly against the existence of psychic phenomena. Even before any experiment is conducted, we must admit that psychic phenomena are unlikely to exist. Our experimental results must be evaluated in light of that prior probability.

Thus, parapsychology is and should be held to a higher burden of proof than other branches of science. We should demand more rigorous experimental designs, stronger effects, and smaller p values. This XKCD presents a similar idea, if you substitute "psychic phenomena exist" for "the sun has gone nova":

http://www.explainxkcd.com/wiki/index.php?title=1132:_Freque...

[1] I say "pseudo" because I'm not a statistician by trade. I'm basing my argument on my rather superficial understanding of Bayesian statistics. I still think it's a valid argument in its own right, but I don't claim that it's an accurate representation of Bayesian statistics.

[ChuckMcM]

Parapsychology aims to prove hypotheses that lacks theoretical foundations.

This is the lynch pin for most scientists. Before you can have a hypothesis, you must have a theory, and you can work to prove or disprove that theory by experimenting to create or observe results that the theory predicts. Parapsychology doesn't have good, testable, theories. Rather it has some interesting unexplained correlations.

[pjreddie]

Doctors rejected hand washing for a long time because there was no theory behind why it would improve patient care, even when there was overwhelming evidence showing it decreased mortality rates.

Do you discount all evidence that doesn't fit into your world view? Maybe theory hasn't caught up with evidence yet.

[kansface]

The answer of course is no. The degree to which we think its shit is related to how much we know about related fields and the size of the effect among others. The prior isn't binary.

For the topic at hand, ESP would most likely invalidate quite a bit of physics no one is questioning for other reasons and there is no proposed theory to explain the effects. Our confidence in the studies is rightfully close to zero.

[jarrett]

> Doctors rejected hand washing for a long time because there was no theory behind why it would improve patient care

The germ theory of disease and experiments supporting the theory predate medical sanitation. (Pasteur's work did come after, but he wasn't the first.) The medical community's initial rejection of handwashing was not due to a scientifically motivated demand for a sound theory. Rather, it was due in large part to doctors' unwillingness to believe that they were the ones spreading disease from patient to patient. Additionally, the medical community at the time did not embrace the scientific method to the extent that it does today. Had it, handwashing would have been evaluated in a controlled study and proven effective.

[pjreddie]

http://en.wikipedia.org/wiki/Ignaz_Semmelweis

> Despite various publications of results where hand-washing reduced mortality to below 1%, Semmelweis's observations conflicted with the established scientific and medical opinions of the time and his ideas were rejected by the medical community. Some doctors were offended at the suggestion that they should wash their hands and Semmelweis could offer no acceptable scientific explanation for his findings.

He published a lot on the subject and was rejected because it didn't fit in with how doctors saw the world and he had no theory to back up his findings. It wasn't until Pasteur that germ theory gained any widespread acceptance so it's pretty irrelevant that other people thought of it first.

Plenty of things are evaluated in controlled studies and still rejected today. For example, the article that you presumably just read discusses one such thing.

[Retric]

Individual experiments give false positives and false negatives all the time. Think about how you might film this using a fair coin: http://www.youtube.com/watch?v=X1uJD1O3L08 Hint 10 heads is only a 1/1024 chance but 1024 is not that rare. Now realise that 5 coin flips is a 1/32 chance and 1/20 is considered acceptable to publish...

Science is not based on a single experiment it's based around replication of experiments by different people at different times using slightly different methods. Parapsychology repeatedly fails this test to the point where there is a million dollar prize for anyone that can demonstrate anything in a controlled setting.

[jmcmichael]

The process to win Randi's prize is not science, it is public relations for the ideology of elimination materialism.

Science is the testing of a hypothesis by applying an instrumental injunction to reality, apprehending and analyzing the results, and sharing/verifying the results in with a community of experts who have also performed the same injunction (reproducibility).

Randi's process shares none of these characteristics with the scientific process. It is entertainment, a publicity stunt that has little to do with science other than to muddle the waters when discussing these topics.

[onetwofiveten]

There are two differences. The first is that you have to replace "preconceived notions of how the universe works" with "vast body of experimental data and scientific understanding of how the universe works". Our evidence for how physics works vastly outweighs current parapsychology research results. The second difference is that the evidence is not being ignored (at least by the author of the article), but is being taken to indicate a real effect, it just isn't the effect of psychic powers. Our knowledge of physics means that the existence of psychic powers is given a much lower prior probability than the possibility of widespread experimental error and bias. Since both explanations are likely to produce slight positive results, the existence of psychic powers is still unlikely once you take the evidence into account.

However, the important point in the article is that in order to make this inference in an intellectually honest way, you need to significantly increase your estimation for the probabilities of widespread experimental error in ALL scientific studies that use similar methods. Since the methods in parapsychology are pretty good, this has quite a far reaching effect.

In a sense, your question about "on what grounds can people claim one field to be nonsense but not others?" is exactly the same question asked by the author. Except the author isn't implying that parapsychology isn't nonsense, they are implying that many other fields are nonsense too. This makes sense because physics is almost certainly not nonsense.

[gwern]

One man's modus ponens is another man's modus tollens (http://www.gwern.net/Prediction%20markets#modus-tollens-vs-m...).

[tomp]

Have you read the article? It's basically all along this problem...

tl;dr: Yes, that is intellectually dishonest, which is a huge problem. Scientists have two options: (1) accept parapsychology as real, or (2) accept that the "scientific method" (in social "sciences", at least) is insufficient. The problem seems to be that Bem (the author of the study) did almost everything "right", and if we increase the bar of scientific proof so that his study is excluded, so are many others...

The reason why parapsychology is excluded: the real world doesn't support it (noone is earning huge amounts of money on the stock market using psi). However, the real world often doesn't support very small effects (e.g. Einstein's relativity). Fortunately for physics, they can afford to make their scientific methods much more rigorous, so they can study large effects as well as exceptionally tiny effects. Social studies can't, for the time being.

[robinh]

Okay, but that's not actually an answer to my question. My question basically comes down to this:

> Yes, that is intellectually dishonest, which is a huge problem. Scientists have two options: (1) accept parapsychology as real, or (2) accept that the "scientific method" (in social "sciences", at least) is insufficient.

I don't get why the whole thing is such a huge problem. The entire problem rests on needing parapsychology effects to not be real. If that need did not exist, we could just go "Okay, interesting, seems likely that there's something to it then. Let's do more research!" because, you know, we take that approach everywhere else. So my question remains: what is it about parapsychology that makes option two even valid to consider? All I can see is people just not liking that that may be how things work.

[lmm]

Parapsychology is physically impossible, and the evidentiary standards in physics are much higher, so we have much more confidence in our physics results than in these experiments - enough that we can reasonably say that physics is true and parapsychology is false.

(But these experiments are as good as many in psychology / social science - suggesting that many "proven" results in psychology / social science could be false)

[dragonwriter]

> Parapsychology is physically impossible, and the evidentiary standards in physics are much higher, so we have much more confidence in our physics results than in these experiments

Conflicting results don't mean one set is impossible (cf., the long-standing apparent conflict between QM and relativity within physics). Apparently conflicting results without a methodological error in either imply that the explanatory model that appears to be supported by at least one of the results (if not both) is, while useful within its own domain, in some way incorrect.

The whole idea that the models validated by scientific experimentation are binarily true of false is, well, missing the point badly. While over time we hope they approach truth with them, what they are is useful (that is, they have predictive power) to a greater or lesser extent. And quite often the models with the greatest predictive power in two different domains conflict when either or both are extend outside of their own domain.

EDIT: The real problem with parapsychology is that there's little in the way of explanatory models being tested anywhere in the field. There's a lot of hypotheses without models and some experiments testing them, which (concerns about methodology aside, for the moment) might raise interesting questions and serve as inspiration for developing and then testing theoretical models to explain the effects, but very little has been done there -- which makes "parapsychology" more a collection of potentially unexplained phenomena more than a branch of science that provides an explanatory model for some set of phenomena.

Which is very different from most of the social sciences.

[DanBC]

> Apparently conflicting results without a methodological error in either imply that the explanatory model that appears to be supported by at least one of the results (if not both) is, while useful within its own domain, in some way incorrect.

When scientist thought they found particles travellig faster than light speed they checked the results, then the equipment, and then they assumed they had made a mistake and asked other people to check the numbers and the experiment. They realised that they had an extraordinary result and they wanted very high degree of rigour.

Some parapsychologists appear to rush to publish weak results and to claim success for flawed experiments.

[gizmo686]

I'm reminded of the history of the measured charge of an electron. The first experiment to measure it was Millikan's oil drop experiment, which got a value smaller than current measurements. As other scientists made their own measurements (with different experiments), the measured value slowly increased. What is interesting in this is that we would not expect to see a gradual increase in the observed value. The explanation for this is that when people find a value that was "to high" they would look harder for sources of error that would increase the value, causing a systemic bias to under-report the charge.

Similarly, with the faster than light neutrino, we spent far more effort looking for mistakes that would make our answer bigger than it should have been, which introduces the same systematic bias.

The solution to this is to realize that science is a time consuming process, and it is okay to take a while to arrive at the right answer. But, if we are aware of these problems, we can get there faster.

[FeepingCreature]

> When scientist thought they found particles travellig faster than light speed they checked the results, then the equipment, and then they assumed they had made a mistake and asked other people to check the numbers and the experiment.

And as it turns out, it was a mistake after all. Physics is solid to a satisfying number of digits after the comma.

[dragonwriter]

> Some parapsychologists appear to rush to publish weak results and to claim success for flawed experiments.

So do some sciences in the supposedly "better" fields [1].

I think the fact of human nature at issue here isn't specific to any particular field of study.

[1] For a particularly well-known example, consider http://en.wikipedia.org/wiki/Cold_fusion#Fleischmann.E2.80.9...

[Houshalter]

Possibly true, but I think beside the point. You are holding parapsychologists to a much higher standard than the rest of science (except physics.) That's what the entire article is about really.

[rainmaking]

Jack Parsons, who was quite into parapsychology, phrased it quite neatly: It's when science becomes closed minded and degenerates into ancestor worship.