The Importance of Evidence

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The Importance of Evidence

Postby JeffN » Mon Feb 20, 2012 11:29 am

The following was written by Richard Dawkins to his daughter and while written more towards the discussion between religion and science, it contains much useful insight information on how we look at and evaluate health information.

I would add in another comment, blind trust of authorities, who sound like they are coming with solid evidence, is not better. We really must learn not only how to evaluate evidence but those who deliver it.

In Health
Jeff

PS, I have no comment in regard to his view/comments on religions or mine. :)

To my dearest daughter,

Now that you are ten, I want to write to you about something that is important to me. Have you ever wondered how we know the things that we know? How do we know, for instance, that the stars, which look like tiny pinpricks in the sky, are really huge balls of fire like the Sun and very far away? And how do we know that the Earth is a smaller ball whirling round one of those stars, the Sun?
The answer to these questions is ‘evidence’.

Sometimes evidence means actually seeing (or hearing, feeling, smelling) that something is true. Astronauts have traveled far enough from the Earth to see with their own eyes that it is round. Sometimes our eyes need help. The ‘evening star’ looks like a bright twinkle in the sky but with a telescope you can see that it is a beautiful ball – the planet we call Venus. Something that you learn by direct seeing (or hearing or feeling) is called an observation.

Often evidence isn’t just observation on its own, but observation always lies at the back of it. If there’s been a murder, often nobody (except the murderer and the dead person!) actually observed it. But detectives can gather together lots of other observations which may all point towards a particular suspect. If a person’s fingerprints match those found on a dagger, this is evidence that he touched it. It doesn’t prove that he did the murder, but it can help when it’s joined up with lots of other evidence. Sometimes a detective can think about a whole lot of observations and suddenly realize that they all fall into place and make sense if so-and-so did the murder.

Scientists (the specialists in discovering what is true about the world and the universe) often work like detectives. They make a guess (called a hypothesis) about what might be true. They then say to themselves: if that were really true, we ought to see so-and-so. This is called a prediction. For example, if the world is really round, we can predict that a traveler, going on and on in the same direction, should eventually find himself back where he started. When a doctor says that you have measles he doesn’t take one look at you and see measles. His first look gives him a hypothesis that you may have measles. Then he says to himself: if she really has measles, I ought to see__Then he runs through his list of predictions and tests them with his eyes (have you got spots?), his hands (is your forehead hot?), and his ears (does your chest wheeze in a measly way?). Only then does he make his decision and say, ‘I diagnose that the child has measles.’ Sometimes doctors need to do other tests like blood tests or X-rays, which help their eyes, hands and ears to make observations.

The way scientists use evidence to learn about the world is much cleverer and more complicated than I can say in a short letter. But now I want to move on from evidence, which is a good reason for believing something, and warn you against three bad reasons for believing anything. They are called ‘tradition’, ‘authority’, and ‘revelation’.

First, tradition. A few months ago, I went on television to have a discussion with about 50 children. These children were invited because they’d been brought up in lots of different religions. Some had been brought up as Christians, others as Jews, Muslims, Hindus, Sikhs. The man with the microphone went from child to child, asking them what they believed. What they said shows up exactly what I mean by ‘tradition’. Their beliefs turned out to have no connection with evidence. They just trotted out the beliefs of their parents and grandparents, which, in turn, were not based upon evidence either. They said things like, ‘We Hindus believe so and so.’ ‘We Muslims believe such and such.’ ‘We Christians believe something else.’ Of course, since they all believed different things, they couldn’t all be right. The man with the microphone seemed to think this quite proper, and he didn’t even try to get them to argue out their differences with each other. But that isn’t the point I want to make. I simply want to ask where their beliefs came from. They came from tradition. Tradition means beliefs handed down from grandparent to parent to child, and so on. Or from books handed down through the centuries. Traditional beliefs often start from almost nothing; perhaps somebody just makes them up originally, like the stories about Thor and Zeus. But after they’ve been handed down over some centuries, the mere fact that they are so old makes them seem special. People believe things simply because people have believed the same thing over centuries. That’s tradition. The trouble with tradition is that, no matter how long ago a story was made up, it is still exactly as true or untrue as the original story was. If you make up a story that isn’t true, handing it down over any number of centuries doesn’t make it any truer!

Most people in England have been baptized into the Church of England, but this is only one of many branches of the Christian religion. There are other branches such as the Russian Orthodox, the Roman Catholic and the Methodist churches. They all believe different things. The Jewish religion and the Muslim religion are a bit more different still; and there are different kinds of Jews and of Muslims. People who believe even slightly different things from each other often go to war over their disagreements. So you might think that they must have some pretty good reasons – evidence – for believing what they believe. But actually their different beliefs are entirely due to different traditions. Let’s talk about one particular tradition. Roman Catholics believe that Mary, the mother of Jesus, was so special that she didn’t die but was lifted bodily into Heaven. Other Christian traditions disagree, saying that Mary did die like anybody else. These other religions don’t talk about her much and, unlike Roman Catholics, they don’t call her the ‘Queen of Heaven’. The tradition that Mary’s body was lifted into Heaven is not a very old one. The Bible says nothing about how or when she died; in fact the poor woman is scarcely mentioned in the Bible at all. The belief that her body was lifted into Heaven wasn’t invented until about six centuries after Jesus’s time. At first it was just made up, in the same way as any story like Snow White was made up. But, over the centuries, it grew into a tradition and people started to take it seriously simply because the story had been handed down over so many generations. The older the tradition became, the more people took it seriously. It finally was written down as an official Roman Catholic belief only very recently, in 1950. But the story was no more true in 1950 than it was when it was first invented 600 years after Mary’s death.

I’ll come back to tradition at the end of my letter, and look at it in another way. But first I must deal with the two other bad reasons for believing in anything: authority and revelation. Authority, as a reason for believing something, means believing it because you are told to believe it by somebody important. In the Roman Catholic Church, the Pope is the most important person, and people believe he must be right just because he is the Pope. In one branch of the Muslim religion, the important people are old men with beards called Ayatollahs. Lots of young Muslims are prepared to commit murder, purely because the Ayatollahs in a faraway country tell them to.

When I say that it was only in 1950 that Roman Catholics were finally told that they had to believe that Mary’s body shot off to Heaven, what I mean is that in 1950 the Pope told people that they had to believe it. That was it. The Pope said it was true, so it had to be true! Now, probably some of the things that Pope said in his life were true and some were not true. There is no good reason why, just because he was the Pope, you should believe everything he said, any more than you believe everything that lots of other people say. The present Pope has ordered his followers not to limit the number of babies they have. If people follow his authority as slavishly as he would wish, the results could be terrible famines, diseases and wars, caused by overcrowding.

Of course, even in science, sometimes we haven’t seen the evidence ourselves and we have to take somebody else’s word for it. I haven’t with my own eyes, seen the evidence that light travels at a speed of 186,000 miles per second. Instead, I believe books that tell me the speed of light. This looks like ‘authority’. But actually it is much better than authority because the people who wrote the books have seen the evidence and anyone is free to look carefully at the evidence whenever they want. That is very comforting. But not even the priests claim that there is any evidence for their story about Mary’s body zooming off to Heaven.

The third kind of bad reason for believing anything is called ‘revelation’. If you had asked the Pope in 1950 how he knew that Mary’s body disappeared into Heaven, he would probably have said that it had been ‘revealed’ to him. He shut himself in his room and prayed for guidance. He thought and thought, all by himself, and he became more and more sure inside himself. When religious people just have a feeling inside themselves that something must be true, even though there is no evidence that it is true, they call their feeling ‘revelation’. It isn’t only popes who claim to have revelations. Lots of religious people do. It is one of their main reasons for believing the things that they do believe. But is it a good reason? Suppose I told you that your dog was dead. You’d be very upset, and you’d probably say, ‘Are you sure? How do you know? How did it happen?’ Now suppose I answered: ‘I don’t actually know that Pepe is dead. I have no evidence. I just have this funny feeling deep inside me that he is dead.’ You’d be pretty cross with me for scaring you, because you’d know that an inside ‘feeling’ on its own is not a good reason for believing that a whippet is dead. You need evidence. We all have inside feelings from time to time, and sometimes they turn out to be right and sometimes they don’t. Anyway, different people have opposite feelings, so how are we to decide whose feeling is right? The only way to be sure that a dog is dead is to see him dead, or hear that his heart has stopped; or be told by somebody who has seen or heard some real evidence that he is dead.

People sometimes say that you must believe in feelings deep inside, otherwise you’d never be confident of things like ‘My wife loves me’.
But this is a bad argument. There can be plenty of evidence that somebody loves you. All through the day when you are with somebody who loves you, you see and hear lots of little tidbits of evidence, and they all add up. It isn’t purely inside feeling, like the feeling that priests call revelation. There are outside things to back up the inside feeling: looks in the eye, tender notes in the voice, little favors and kindnesses; this is all real evidence. Sometimes people have a strong inside feeling that somebody loves them when it is not based upon any evidence, and then they are likely to be completely wrong. There are people with a strong inside feeling that a famous film star loves them, when really the film star hasn’t even met them. People like that are ill in their minds. Inside feelings must be backed up by evidence, otherwise you just can’t trust them.

Inside feelings are valuable in science too, but only for giving you ideas that you later test by looking for evidence. A scientist can have a ‘hunch’ about an idea that just ‘feels’ right. In itself, this is not a good reason for believing something. But it can be a good reason for spending some time doing a particular experiment, or looking in a particular way for evidence. Scientists use inside feelings all the time to get ideas. But they are not worth anything until they are supported by evidence.

I promised that I’d come back to tradition, and look at it in another way. I want to try to explain why tradition is so important to us. All animals are built (by the process called evolution) to survive in the normal place in which their kind live. Lions are built to be good at surviving on the plains of Africa. Crayfish are built to be good at surviving in fresh water, while lobsters are built to be good at surviving in the salt sea. People are animals too, and we are built to be good at surviving in a world full of other people. Most of us don’t hunt for our own food like lions or lobsters, we buy it from other people who have bought it from yet other people. We ‘swim’ through a ‘sea of people’. Just as a fish needs gills to survive in water, people need brains that make them able to deal with other people. Just as the sea is full of salt water, the sea of people is full of difficult things to learn. Like language.

You speak English but your friend speaks German. You each speak the language that fits you to ‘swim about’ in your own separate ‘people sea’. Language is passed down by tradition. There is no other way. In England, Pepe is a dog. In Germany he is ein Hund. Neither of these words is more correct, or more truer than the other. Both are simply handed down. In order to be good at ‘swimming about in their people sea’, children have to learn the language of their own country, and lots of other things about their own people; and this means that they have to absorb, like blotting paper, an enormous amount of traditional information. (Remember that traditional information just means things that are handed down from grandparents to parents to children.) The child’s brain has to be a sucker for traditional information. And the child can’t be expected to sort out good and useful traditional information, like the words of a language, from bad or silly traditional information, like believing in witches and devils and ever-living virgins.

It’s a pity, but it can’t help being the case, that because children have to be suckers for traditional information, they are likely to believe anything the grown-ups tell them, whether true or false, right or wrong. Lots of what grown-ups tell them is true and based on evidence or at least sensible. But if some of it is false, silly or even wicked, there is nothing to stop the children believing that too. Now, when the children grow up, what do they do? Well, of course, they tell it to the next generation of children. So, once something gets itself strongly believed (even if its completely untrue and there never was any reason to believe it in the first place) it can go on forever.
Could this be what happened with religions? Belief that there is a god or gods, belief in Heaven, belief that Mary never died, belief that Jesus never had a human father, belief that prayers are answered, belief that wine turns into blood – not one of these beliefs is backed up by any good evidence. Yet millions of people believe them. Perhaps this is because they were told to believe them when they were young enough to believe anything.

Millions of other people believe quite different things, because they were told different things when they were children. Muslim children are told different things from Christian children, and both grow up utterly convinced that they are right and the others are wrong. Even within Christians, Roman Catholics believe different things from Church of England people or Episcopalians, Shakers or Quakers, Mormons or Holy Rollers, and all are utterly convinced that they are right and the others are wrong. They believe different things for exactly the same kind of reason as you speak English and someone speaks German.

Both languages are, in their own country, the right language to speak. But it can’t be true that different religions are right in their own countries, because different religions claim that opposite things are true. Mary can’t be alive in the Catholic Republic but dead in Protestant Northern Ireland.

What can we do about all this? It is not easy for you to do anything, because you are only ten. But you could try this. Next time somebody tells you something that sounds important, think to yourself: ‘Is this the kind of thing that people probably know because of evidence? Or is it the kind of thing that people only believe because of tradition, authority or revelation?’ And, next time somebody tells you that something is true, why not say to them: ‘What kind of evidence is there for that?’ And if they can’t give you a good answer, I hope you’ll think very carefully before you believe a word they say.

Your loving,
Daddy
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Re: The Importance of Evidencehi

Postby giddyupgin » Mon Feb 20, 2012 12:49 pm

What a great letter. What a great explanation. Thanks for sharing this Jeff.
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Re: The Importance of Evidence

Postby JeffN » Mon Feb 20, 2012 1:08 pm

I started making a similar point about 2.5 years ago as part of the intro to some of my talks and have continued to do so on many occasions.

I showed a few slides on "Who Do You Believe" and discuss the concepts of "Burden of Proof" and the accepted "Standards (Hierarchy) of Evidence."

I also discuss the 3 different categories that most health information falls under, which are similar to the 4 he describes above (evidence, tradition, revelation and authority).

My three were

1) Science & Evidence Based

2) Advertising/Marketing

3) Guru/philosophical/religious.

The main point was the same.

Here is the slide on the Standards of Evidence

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Re: The Importance of Evidence

Postby Knut » Mon Feb 20, 2012 5:00 pm

Well done...
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Re: The Importance of Evidence

Postby giddyupgin » Mon Feb 20, 2012 7:09 pm

Wasn't here 2 1/2 years ago. Some things are just worth repeating. Thanks again!
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Re: The Importance of Evidence

Postby michaelswarm » Mon Feb 20, 2012 7:33 pm

Jeff,

Very good letter by Dawkins.

Dawkins doesn't mention clinical trials at all, just observations and predictions. And Darwin came up with natural selection after sailing around the world and collecting specimens with his eyes open.
Pyramid less so. There are some really good ideas, and some very poorly done double blind randomized controlled trials, and shades of quality between.

I'm not ready to throw the baby out with the bath water, but a heavy use of large populations and statistics is common in medical research, but not most other branches of science.
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Re: The Importance of Evidence

Postby JeffN » Mon Feb 20, 2012 7:40 pm

michaelswarm wrote:Dawkins doesn't mention clinical trials at all, just observations and predictions


To his defense, he discussed the process in general and then says, ..

"The way scientists use evidence to learn about the world is much cleverer and more complicated than I can say in a short letter."

michaelswarm wrote: There are some really good ideas,


No doubt, but for them to be "evidence" they need to go through some sort of validation process. And, any good idea should be willing to go through the process.

michaelswarm wrote:and some very poorly done double blind randomized controlled trials, and shades of quality between.


That is part of my talk too. That even once we establish the pyramid, we then have to learn how to evaluate evidence at each level and as not all RCT's are the same. And, there are standards of how to evaluate within and between the two (ie, are 8 very well done population studies worth more than one short term, small RCT?)

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Re: The Importance of Evidence

Postby Katydid » Tue Feb 21, 2012 10:12 am

Great post, Jeff! Whenever I come across the latest 'miracle cure' I like to apply Carl Sagan's Baloney Dectection Kit from 'The Demon Haunted World' (one of my favorite books of all time). For those not familiar, here is a link:

http://www.xenu.net/archive/baloney_detection.html

I just wish I could get my friend at work to think logically. He saw a YouTube video the other day, and is now convinced that the government and medical establishment are in cohoots to surpress hemp oil because it is a miracle cure for cancer. Sigh.

Kate
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Re: The Importance of Evidence

Postby giddyupgin » Tue Feb 21, 2012 12:31 pm

Katydid wrote:Great post, Jeff! Whenever I come across the latest 'miracle cure' I like to apply Carl Sagan's Baloney Dectection Kit from 'The Demon Haunted World' (one of my favorite books of all time). For those not familiar, here is a link:

http://www.xenu.net/archive/baloney_detection.html

I just wish I could get my friend at work to think logically. He saw a YouTube video the other day, and is now convinced that the government and medical establishment are in cohoots to surpress hemp oil because it is a miracle cure for cancer. Sigh.

Kate



This us great! Love this Baloney Detection Kit.
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Re: The Importance of Evidence

Postby noelalexis2000 » Wed Feb 22, 2012 8:11 am

Katydid wrote:Great post, Jeff! Whenever I come across the latest 'miracle cure' I like to apply Carl Sagan's Baloney Dectection Kit from 'The Demon Haunted World' (one of my favorite books of all time). For those not familiar, here is a link:

http://www.xenu.net/archive/baloney_detection.html

I just wish I could get my friend at work to think logically. He saw a YouTube video the other day, and is now convinced that the government and medical establishment are in cohoots to surpress hemp oil because it is a miracle cure for cancer. Sigh.

Kate


Great topic. Thanks, Jeff! Had not seen the video Kate but enjoyed it very much. Thanks!
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Re: The Importance of Evidence

Postby JeffN » Wed Feb 22, 2012 8:16 am

One of the comments I make when discussing the above, is that of course any system will have its limitations and many people like to point out the limitations with the above system.

So, if for some reason you disagree with the above system of evidence, then what system do you use? And, if you choose to use a different system, then shouldn't it be a better system?

Many people who say the system is flawed then make their decisions based on a lesser system (ie, youtube video, neighbors comments, commercial on TV, etc etc) which makes absolutely no sense.

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Re: The Importance of Evidence

Postby didi » Thu Feb 23, 2012 4:40 am

Pondering eternal questions is hardly the same thing as deciding which breakfast cereal to eat. I assume little Miss Dawkins will someday grow up and be on her own. When life bites her on the *** as life quite frequently does, and having learned that science is the answer, I predict she will receive cold comfort from the double blind cross over studies she has learned to rely on.

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Re: The Importance of Evidence

Postby JeffN » Thu Feb 23, 2012 7:14 am

This sounds like a harsh response to some good advice about the importance of logic, reason & critical thinking.

He is not asking his daughter, or anyone else, to ignore other aspects of the human experience, to only rely only on "double blind cross over studies," or to be a robot.

Sometimes when I'm teaching and put a slide up that has examples of something (ie, oils, grains, fruits, etc) someone will ask, "i don't see "x" up there so are you saying that "x" is no good? Why did you leave it out"

To which I'll respond, "I left "x" (& others out) because there are many more examples but I ran out of room." :)

Sometimes a cigar is just a cigar.

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Re: The Importance of Evidence

Postby didi » Thu Feb 23, 2012 8:00 am

Actually, he IS asking his daughter to ignore some aspects of the human experience--making sense out of a very large and mostly unknowable and, natural physical laws aside, unpredictable universe (quantum mechanics anyone?).

The very great irony in all this is that parents whose tradition is to have faith in the unseen (but I would propose, not unfelt) often find their children rejecting that tradition and others like Madeleine Murray O'hare who have raised their children to have faith in only the physically demonstrable see their offspring embrace exactly the position they have argued against vociferously and publicly.

I have never seen anyone quantify feelings or emotions or passion or love or faith or trust with any scientific certainty (except maybe the ubiquitous question--on a scale of one to ten how do you feel?) So the example of the letter is irrelevant as far as choosing which diet you will follow.

As everyone on this group knows very well, and is apparent by the questions that are asked, there are many many studies which purport to be accurate and which, in many cases are contradictory. And for the period of time and number of subjects seem to get accurate results. Most of us do not have the expertise or the wherewithal to know with certainty which "evidence" is correct. So I would ask you--how many people on this group rely on the evidence either Jeff or Dr. McDougall present and do not search out original sources or seek other sources which contain studies that are contradictory? So in the end, so many on this group (and other groups with exactly opposite opinions) rely on the guru of their choice. And anyway you look at it--this is following tradition. Check out webmd diabetes support group or Dave Mendosa's low carb web site. You will find lots of studies proving that low carb is best. Do you believe them? I don't. I have chosen another "tradition".

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Re: The Importance of Evidence

Postby JeffN » Thu Feb 23, 2012 8:04 am

As I said above

"That even once we establish the pyramid, we then have to learn how to evaluate evidence at each level and as not all RCT's are the same. And, there are standards of how to evaluate within and between the two (ie, are 8 very well done population studies worth more than one short term, small RCT?)"

So yes, we have to learn to evaluate studies also, for power, strength, significance, methodology etc.

I am not asking anyone to have a guru but to become their own guru, which if you heard the talk and/or discussion about the above slide I posted, that is the top box on the pyramid which I left blank.

Sure, it is a process that takes some time and some learning but why not learn it?

Apparently, everyone who is here has taken the time and effort to figure out how to successfully navigate the world of the internet, and computers. The process, or the ability to learn it, is no different for anything else, we just have to apply it. And, we all use and have applied the same process and the same logic and reasoning in so many other areas each and everyday.

So, there is no "novickian" plan and I ask no one to blindly follow my recommendations nor can you find any specific detailed recommendations of mine, but instead, help them to understand the process of finding the truth for themselves.

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