Friday, August 27, 2010

Knowledge and certainty - II

Errors, like straws, upon the surface flow;
He who would search for pearls must dive below.
- John Dryden

Once, when some painting work was going on in our house, a painter stood in my room watching the physiotherapist give me exercises. He asked many questions about my stroke and said that he had heard that if you got a cracking sound when the fingers or toes are pulled, it meant that the limb was normal. The physiotherapist said that it was just the sound of air bubbles popping in a fluid in the joints and was not of great significance. But the painter refused to accept the explanation and started pulling my toes.

I wondered how a person who probably knew nothing about the functioning of the human body could argue so confidently with someone who had studied about it for years. The physiotherapist said that this happened frequently in the hospital. When he would be giving exercise to a person, somebody will come up and say that some other exercise should be given.

Over the years I decided on a rule of thumb for making out whether a person knew what he was talking about. He will use words like 'it depends', talk about side effects, likely complications, failure rates etc. As David Quammen said in The Boilerplate Rhino:
Having had many chances to study scientists as they study nature, I've seen that science itself is a fallible human activity, not a conceptual machine-tool, and that while accuracy and precision can be easily achieved, validity and meaning cannot. The imperfections and constraints vitiating scientific knowledge stand as a warning about the limits of other sorts of knowledge - even shakier sorts - including that based on eyewitness experience. Moral: We live in a tricky universe, and it behooves us to be just a bit provisional about our convictions.
Carl Sagan wrote in The Demon-Haunted World:
Humans may crave absolute certainty; they may aspire to it; they may pretend, as partisans of certain religions do, to have attained it. But the history of science - by far the most successful claim to knowledge accessible to humans - teaches that the most we can hope for is successive improvement in our understanding, learning from our mistakes, an asymptotic approach to the Universe, but with the proviso that absolute certainty will always elude us.

We will always be mired in error. The most each generation can hope for is to reduce the error bars a little, and to add to the body of data to which error bars apply. The error bar is a pervasive, visible self-assessment of the reliability of our knowledge.
On the other hand a person with a tenuous grasp of the subject being discussed, being unencumbered by any knowledge of the subtleties involved, will try to sell you lemon juice giving you 'hundred percent guarantee'. As H. L. Mencken said, "For every complex problem there is an answer that is clear, simple, and wrong."

Unfortunately it seems that we’re swayed by confidence more than expertise.(I know, I know you are not one of those. It is about others.) Many people also have a poor grasp of probability. (I am not very good at it. I keep getting surprised by the answers to various questions.) Perhaps Arthur Benjamin's suggestion needs to be considered.

Saturday, August 14, 2010

Knowledge and certainty - I

The fool thinks himself to be wise, but the wise man knows himself to be a fool.- William Shakespeare

Among many cognitive biases (apparently most people - not you of course - have ‘bias blind spot’) is The Dunning-Kruger effect which is the phenomenon whereby people who have little knowledge systematically think that they know more than others who have much more knowledge. One curious aspect you may have noticed is that they tend to become bosses. Charles Darwin knew about this illusion of confidence and said that "ignorance more frequently begets confidence than does knowledge". In Bad Science, Ben Goldacre said:
Today, scientists and doctors find themselves outnumbered and outgunned by vast armies of individuals who feel entitled to pass judgement on matters of evidence - an admirable aspiration - without troubling themselves to obtain a basic understanding of the issues.
Later he says:
I spend a lot of time talking to people who disagree with me - I would go so far as to say that it's my favourite leisure activity - and repeatedly I meet individuals who are eager to share their views on science despite the fact that they have never done an experiment. They have never tested an idea for themselves, using their own hands; or seen the results of that test, using their own eyes; and they have never thought carefully about what those results mean for the idea they are testing, using their own brain. To these people 'science' is a monolith, a mystery and an authority, rather than a method.
The arrogance of ignorance is often seen when you have a medical problem.(This is exacerbated by distrust of Big Pharma due to Marketing-Based Medicine and other machinations.) If you cut your finger and the doctor prescribes an ointment, the servant will scoff at it and say that the best cure is a paste made by crushing the roots of a particular plant. If the doctor advises 3 weeks' bed rest for a bad back, your cousin's friend (who is a brilliant Chartered Accountant you are told) will tell you with evangelical insistence about a protein drink that can cure all aches and pains within a week. Being a brilliant CA doesn't qualify you to give medical advice.The transfer of expertise from one area to another often has errors.

People who have got their medical knowledge from dumbed down news reports will speak with great confidence about cures for various problems.You will be told,"My father was given a particular piece of advice for some ailment and now I am being told something else for the same ailment. These guys don't know anything." But all errors are not equal.As the physicist Richard Feynman once wrote, science creates an “expanding frontier of ignorance” where a discovery leads to more questions which lead to more discoveries.

Wednesday, August 4, 2010

Which hospital?

Once Jaya had to stay over-night at a hospital to look after a relative's child because nobody could stay due to various reasons. That evening, when the physiotherapist came, he asked me the name of the hospital to which Jaya had gone. I didn't blink for any name that he mentioned, which puzzled him.

If everyone took his cue from the noted intellectual , George Bush and said "I don’t do nuance", communication with me would have quickly reached a dead-end. But this physiotherapist was made of sterner stuff. Like Sherlock Holmes' dog that did not bark, the absence of my usual communication meant something and he was determined to get to the bottom of it.

He tried to think of hospitals that he had missed. He wondered if some hospital had an unusual name but realised that whatever it was, I should have been able to dictate it. (He had some familiarity with my communication system.) He wondered whether the hospital was outside Coimbatore to which I replied in the negative. He might have found a Watson-like computer useful but not having access to one, he asked Sujit to try his luck. Sujit tried his methods but was unsuccessful and he concluded that I was playing the fool.

Suddenly the physiotherapist had a thought and asked me: Do you know the name of the hospital - yes/no? I blinked for 'no' - I didn't know the name!