Evidence based:
There is a current flurry of interest in “evidence based” things.  For instance in education, if someone proposes some sort of reform it is now expected that there should be some sort of study that has been done to support it.  This is a vast improvement over the attitude when I was young that children simply needed to be unleashed in order to learn.  Someone pointed out that if you ask third graders whether they can draw, the answer is yes indeed, and they will be eager to show off.  But if you asked teenagers the same question, the answer would be no and they would not be happy to have their work seen.  The conclusion was that somehow the spontaneity of childhood had been regimented out of the older youths, and all that was needed was to restore it.  I would have thought that the teenagers were thinking, no, I cannot draw because nobody ever showed me how and encouraged me to put in the requisite practice.  If I try, it will look like a child’s work.

The unleash-them theory of education was introduced without the slightest thread of evidence.  So certainly evidence-based is an improvement over that.  And I am totally in favor of examining evidence.  I take pains when I can to present references to support any claim I make.  When I provide no references, as I shall not at the present time, I do not expect to be taken seriously.  If you find what I say helpful, well and good.  If not, just ignore it.  I didn’t have evidence. 

The problem with evidence is that it must be assembled in a formal fashion.  You have to look at something, make a record, and go back and look again.  You change something and see what happens if you are doing science.  If you are investigating a crime you look for corroborating evidence for every clue that looks like it is adding up to a picture.  Evidence does not just happen.  You make it in partnership with the reality that interests you.

If you don’t ask the right question then you won’t have the right evidence. 

Sometimes evidence can get you into trouble.  The great ancient astronomer Ptolemy watched the sky for a long time and decided that the earth was the center of the universe.  The sun and other heavenly bodies were revolving around the earth.  So he proposed great crystalline spheres by which these luminous objects were carried.  The problem was that, as seen from earth, that can’t be quite so.  The earth goes around the sun in less time than, say, Jupiter.  The result is that the earth overtakes Jupiter at certain times.  From the earth it looks like Jupiter has reversed its direction.  Ptolemy resolved this by inventing yet more crystalline spheres.  Jupiter is imbedded in a sphere rolling on a sphere.  This was consistent with the evidence he had. 

Centuries later Copernicus thought it was more elegant to put the sun at the center of the system with the earth and planets going around it in circles.  That approximately accounted for the reversal of planets like Jupiter.  Galileo turned his telescope skyward and saw that Venus goes through phases just like the moon.  He chose to believe Copernicus over Ptolemy and got into serious trouble with the Inquisition for his efforts.

I was once at a carnival where the entertainment was to take people from the audience in the tent and give them symbols for the planets, the sun, earth and moon.  He then had Galileo, interpreted by a teenage boy, direct the planets to move in a heliocentric fashion with the people drawn from the audience following their assigned paths.  Then someone portraying a favorite of the Inquisition, interpreted by a middle aged man, had the same people demonstrate the Ptolemaic universe. 

Problems arose in my mind.  For one thing, Galileo was no boy at the time in question; he was more like sixty eight.  And although he was portrayed as having no idea why certain planets reversed themselves, that was in fact Ptolemy’s strength.

So Galileo was punished for believing evidence over instruction and became sort of a saint of science.  If there is a moral in that story, it cannot be a good one. 

Later a man named Tycho Brahe, did some very careful measurements of the movements of the planets and concluded that the circles of Copernicus simply would not jibe with the real sky, while the epicycles of Ptolemy worked just fine.  Sorry about the phases of Venus.  The phases show that sometimes Venus is close to the sun and looks like a crescent.  Sometimes at the same apparent distance from the sun it is almost round.   It’s hard to do that with Ptolemy’s model unless the crystalline sphere can pass through each other.  But Brahe was using a long iron bar and no telescope for his measurements. 

There is another problem with evidence.  It is the, “If it is not observed by my equipment it doesn’t exist,” attitude. 

Finally one of Brahe’s students, Kepler, worked it out.  Newton also worked it out using his theory of gravity, but the mathematics reduces to the same thing.  Kepler stood until Einstein rendered the whole thing impenetrable to the ordinary mind, but he did account for observations nobody had made until that time.

Brahe looked for corroborating evidence just as Galileo had done.  He reasoned that if the sun were at the center and the earth going around it, and if the stars were like the sun but scattered in three dimensions, then the nearer stars must appear to move compared with more distant stars as seen from the earth as the earth moves around the sun.  He looked for this and found they did not move relative to each other.  “My equipment,” strikes again.  The do appear to move, but less than he was able to measure.  He did calculate how accurate his iron bar was and calculated a minimum distance to stars.  The result was a distance so vast that he dismissed it as absurd. 

At the carnival, the final question posed to the audience was, “Which explanation is simpler?”  But it was as if they asked, “Which explanation do you like?” since in fact Ptolemy was more accurate than Copernicus and Galileo.  That was the argument brought against Darwin’s by Archbishop Wilburforce when the matter was debated.  It’s not a good argument.  In fact Welburforce was a liberal.  Some times in the dead of night I suspect him of having deliberately thrown the debate.  Huxley, who was arguing on behalf of Darwin, made short work of it. 

Yes, evidence can get you into trouble.  The thing is you don’t have anything else to go on. 

More recently Michael Shermer of the Scientific American, was writing I believe about nuclear war.  I was not so worried about it then as I am now.  In those days two competing but inherently rational governments had just about all the nuclear weapons.  Now there are more governments with such weapons, and the new governments are not all completely dependable. 

What Shermer did was notice that we haven’t heard from other planets and raised the question, “Do intelligent beings inevitably destroy themselves?”  He pulled out the encyclopedia and looked up how long civilizations last.  His average was, of course, not reassuring.

I had already done a similar analysis.  But apparently Shermer got his average from a calculator.  I didn’t know how to use the calculator for that, so I used a statistics program I had.  The program handed over the aveage and then asked, “Would you like to see the data graphed?”  I pressed the “yes” button and my life has not been the same since. 

I should have written Shermer at the time and pointed this out.  In fact, I think I did, but I have lost the record of the communication.  (No references today, right?)  Of course he did not answer – would not have answered.  My analysis was not germane to his subject.  Give the man his due.  He did take the trouble to pull out some evidence.  But if you do not ask the question you do not get the answer.

So evidence can lead you astray.  You still have to use your brain.  And even then there is no assurance that you have the important question in mind.

My emotional feel for it is that what we understand of the world is like a drop of brine thrown up from a tempestuous sea. 

I am truly most sincerely sorry.

There have been 5,082 visitors so far.

Home page.