Evidence, Popular Opinion, and Prejudice

[PairTheBoard]

Sklansky has made the following observation:

[ QUOTE ]
DS -
The reason I say that the fact that 90% of people disagreeing with a theory is evidence against it, is because of all theories ever proposed that were eventually settled, those that had 90% disagreeing, turned out to be right much less often than those which had few disagreeing.


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He has claimed that besides me, "Everyone Else Understands" this. So I ask SMP to take a closer look at it. Exactly what is it saying and how useful is it?

If by Sklansky's observation Poplular Opinion is indeed "Evidence", what kind of Evidence is it? Is it mathematical evidence? Is it scientific evidence? Is it aesthetic evidence? Is it evidence that would be admitted in a court of law? Is it common sense evidence?

How persuasive is this Evidence? Is it conclusive evidence? Is it strong evidence? Is it weak evidence? Is it reliable evidence? Is it misleading evidence? Is it Prejudicial evidence?

First, does Sklansky's observation imply Popular Opinion is Mathematical Evidence? In the past Sklansky has made allusions to mathematical support for the implication, sometimes with statements like, "Math tells us". Certainly, the observation is analogous to ones we can make in a mathematical probability or statistics setting. When in that setting it's the kind of observation provided by Bayes Theorem or just Conditional Probability in general. But this is an example of Sophomoric application of math concepts.

People with real in depth knowledge of mathematics tell us that the real problem is in coming up with the mathematical model. When dealing with a Real situation, the assumptions that go into constructing the math model are assumptions made outside of mathematics. I think Sklansky has recently become convinced of this. His observation does not carry the Authority of Mathematics. The Evidence it implies is not Math Evidence.

Does Sklanky's observation imply Scientific Evidence? Not strictly speaking. At least not in general. In a specific instance where the Proposition itself refers to Popular Opinion about it, then empirical data about that Popular Opinion would provide Scientific Evidence about the Proposition. Certain Aesthetic Propositions might fall into this category. But generally we are not talking about such a Proposition. Science needs to apply the scientific method to a Proposition to obtain evidence for it. Science does not look at Popular Opinion about it. Thats' a good thing too, because otherwise we might still be operating under the laws of physics provided us by Aristotle.

Does Sklanky's Observation provide Evidence admissable in a Court of Law? Almost but not quite. And at this point I bring in Sklanky's additional Observation that the Evidence can be improved if we limit our Population of Opinion to that of "brilliant" people. Certainly a court of law would not find admissable the fact that Most People think the defendant is guilty. Neither would the court admit the fact that most "brilliant" people think the defendant is guilty.

However, the court will hear testimony from expert witnesses. And at this level Sklansky's Observation might be allowed as Evidence for what constitutes good science according to the consensus of the scientific community. But that only provides the court with evidence of credibility for the expert witness. That only allows the expert witness to speak. Notice also, the Court would not allow the witness to speak based only on his "brilliance". He must have in depth knowledge of the specific area on which he is to testify.

The Evidence the Court is interested in is, what does the expert-identified scientific evidence say about the Proposition at Bar? The Court will weigh the evidence in making a determination on the Proposition. The Court will decide how the evidence relates to the Proposition. It will not allow itself to be Prejudiced by the opinions others have about the Proposition. The expert witness does not give his opinion about the guilt of the defendant.

So the implication Sklansky claims for his Observation is not Mathematical, Scientific, or Legal. Is it common sense evidence? Well, it is certainly a Natural inferrence for us to make. If we know practically nothing about the Proposition other than the fact that Most People agree with it, we Naturally tend to go along with the crowd and accept it. We are Naturally even more swayed by the consensus of opinion among people who have an in depth knowledge the Proposition's subject.

In subjects beyond our ability to study we have little choice but to accept the consensus of those who are able to study it. And we would naturally give more credence to those who are recognized as Brilliant in that field of study. So this might pass as a common sense way to form our opinions in these situations. However, just at the Court does not allow just any "Brilliant" person to give expert testimony, it does not make common sense for us to give extraordinary weight to the opinon of "Brilliant" people who are speaking outside their area of expertise. Especially if they tend to be Myopically Focused on concepts applicable to their area rather than ones relevant to the Proposition.

We should also recognize that this common sense evidence is not the Best Evidence. It is often unreliable, which is why it is not allowed in a Court of Law. The fact that most people think O.J. did it sways our opinion as weak evidence. The fact that most Legal Experts think he did it sways our opinion as stronger evidence. But the Best Evidence is that which was presented in Court. Those of us who were really interested in the question wanted to see the actual evidence and weigh it ourselves. It does not make common sense to depend on weak evidence when Better evidence is available.

Furthmore, what sometimes passes as common sense often turns out to be anything but good sense. Sklansky's inference can easily degrade into plain everyday Prejudice and bias. Popular opinion can quickly turn into Bigotry, even among the most Brilliant people, depending on the times. The Best Evidence is sometimes our individual conscience.

And when it comes to questions like, "Does God Exist"? Who is an expert? What does the question even mean? How do you decide what the Best Evidence is for questions like this? Nobody, no matter how brilliant, has any kind of track record of accuracy for determining such questions because there is no way making such a determination. Each individual relates to the question his own way. It is ultimately a personal question requiring a personal resolution.

PairTheBoard

[David Sklansky]

Are you implying that something you wrote refutes my quote?

Just to make it clear, let me refer you to my official definition of "evidence". To wit:

Anything that forces you to move the line.

That includes popular opinion. But it doesn't mean that there there doesn't often exists much stronger evidence for the other side. Surely you didn't think that I thought otherwise.

[kerowo]

I think that is an iffy statement because almost by definition every paridigm change has started off with 90% of the population disagreeing with it.

[PairTheBoard]

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Are you implying that something you wrote refutes my quote?


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My post was an attempt to clarify the notion you are promoting. You claimed everybody but me understands what you are saying. I'm actually applying your notion to that claim in the one instance where it best applies. Does everybody here understand what you're saying? Let's find out.

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Just to make it clear, let me refer you to my official definition of "evidence". To wit:

Anything that forces you to move the line.


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"Move the line" is an interesting phrase. As you saw in your Thread on "Belief", not everybody comes to a conviction about the validity of a proposition in "probability" terms. "Move the line" is a reference to "probability" terms.

As I said in my post, it's a Natural Inference to make in the absence of other information. However, it easily Degrades into something far from common sense. It is unreliable. In a court of law it is inadmissable. It's not science and it's not mathematics. That is not a refutation of the fact that it's something we naturally do. But it indicates we need to keep a watchful eye on how we apply it.

Just because it might "move the line" in the absence of better evidence does not mean its Placement of the "Line" in that situation should be the starting point for determining the "Line" once Better Evidence is Available. Once Better information is available we should take an UNBIASED look at it. I think this position IS contrary to your use of the natural inference.

PairTheBoard

[LA_Price]

I would say that whether the wisdom of the crowd should be considered evidence depends entirely on what the proposition is.

If the proposition lives in the world of mediocristan randomness(i.e. normal distriubtion) then I would have to agree with Sklansky. This would be a question like "there are 70 beans in this jar". You could ask a crowd how many beans were in the jar and they would get it reasonbly right and there observations should be counted as evidence to prove or disprove your proposition.

If the proposition lives in world of extremistan("black swan", unpredictable,large impact of highly improbable) I would say no, the crowd can easily be wrong. In this type of world there is also an expert problem, in that there is really no expertise. This would be a proposition like "all swans are white". 90% of the people can think this, and a single observation or outlier will render the proposition false.

This is exactly the topic discussed in Nassim Taleb's new book "The Black Swan".

[Piers]

[ QUOTE ]
The reason I say that the fact that 90% of people disagreeing with a theory is evidence against it, is because of all theories ever proposed that were eventually settled, those that had 90% disagreeing, turned out to be right much less often than those which had few disagreeing.

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Well its kind of ok but a lot depends on perspective.

For a random theory about a subject you know nothing I think it is fine.

However once you understand why say 90% of people disagree with a theory, you can discount the fact that they disagree and use as evidence or otherwise the reason they disagree.

So as a general statement about a random, and yet unspecified theory I think the quoted statement is fine. However once you have specified the theory in question the statement need not be true in general.

[PairTheBoard]

So here's a question. In the absence of Better information we naturally look to Popular Opinion. But suppose we start out with the Better Information. Should we then Bring In Popular Opinion to Prejudice our analysis of the Better Information? This is what I see Sklansky doing.

PairTheBoard

[LA_Price]

In some situations better information doesn't exist and popular opinion doesn't matter.

Imagine you're a turkey in a group of turkeys. Every day the humans come out and give you food and watch you get fat. You have no reason to believe humans are anything but great and friendly. 90%+ of turkey's would think the same thing and keep eating the food the humans give them...and then Thanksgiving comes and you all lose your heads. Prior observation and opinion was rendered useless in a single day.

A proposition like "Does God Exist" lives in the world of extremistan, like the turkeys. We will live our days until the day we die believing one way or the other and then we will either be sent to some heaven or hell(who knows which religion is right) or we will just die and will never know we were right or wrong. 90% of the people believing either way is useless as evidence.

[bunny]

I think it is inferential evidence. As he has said before, more theories-that-have-been-doubted-by-90%-of-smart-people have turned out to be false than turned out to be true.

Thus, we infer that any current theory-that-is-doubted-by-90%-of-smart-people is more likely to turn out to be false than true.

I dont consider it very strong, but it does seem to be evidence of some sort.

[vhawk01]

[ QUOTE ]
In some situations better information doesn't exist and popular opinion doesn't matter.

Imagine you're a turkey in a group of turkeys. Every day the humans come out and give you food and watch you get fat. You have no reason to believe humans are anything but great and friendly. 90%+ of turkey's would think the same thing and keep eating the food the humans give them...and then Thanksgiving comes and you all lose your heads. Prior observation and opinion was rendered useless in a single day.

A proposition like "Does God Exist" lives in the world of extremistan, like the turkeys. We will live our days until the day we die believing one way or the other and then we will either be sent to some heaven or hell(who knows which religion is right) or we will just die and will never know we were right or wrong. 90% of the people believing either way is useless as evidence.

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Awfully results-oriented, don't you think?