Absolutes oder relatives Risiko?

From my Science Column at Tageblatt:

Heutzutage lassen sich viele Kurzsichtige die Augen lasern. Bei der LASIK-Operation wird die Oberfläche der Hornhaut angeschnitten und umgeklappt, dann brennt der Laser die oberste Schicht ab und die Oberfläche wird wieder angeklebt. Der Heilungsprozess ist relativ problem- und schmerzlos, und das Resultat lässt sich sehen: volle Sicht. Ich habe mich LASIK auch unterzogen. Aber, das Risiko ist nicht gleich null: eine von 10.000 Operationen hat laut einer Studie schwere Folgen. Würden Sie LASIK einem Freund empfehlen?

Wie lautet Ihre Antwort? Vielleicht sagen Sie, dass es von der Risikobereitschaft Ihres Freundes abhängt oder davon, wie stark seine Kurzsichtigkeit sein Leben beeinflusst. Wenn ja, haben Sie

Die Papageien und das Alter des Universums

From my Science column at Tageblatt:

Wie alt ist das Universum? Mit dieser Frage nerve ich oft Nicht-Naturwissenschaftler. Ich will aber gern herausfinden, in welcher Welt sie zu leben glauben.

Die interessanteste Antwort bekam ich von einem Baptistenprediger, der auf einem trans-atlantischen Flug nach San Diego neben mir saß: 4000 Jahre! Ich war etwas erschrocken, weil ich noch nie so jemanden getroffen hatte. Ich bat ihn freundlich, mir doch bitte die Fossilienfunde in Jahrmillionen alten geologischen Schichten zu erklären. Er antwortete schnell und selbstbewusst: Ah, das zeigt die Größe Gottes! Er lässt alles so aussehen, als wenn es Millionen

Absolute versus Relative Risk

I wrote this piece for a newspaper:

These days many people have their eyes lasered. They have a LASIK operation to get their short-sightedness corrected. The surface of the eye is cut, a laser burns off a small layer, and the surface is glued back again. The healing process is relatively straightforward and painless, and the results are typically superb. I had LASIK myself. However, the risks are non-zero: 1 out of 10'000 operations is associated with severe problems according to one study. Would you recommend LASIK to a friend? How do you decide?

What is your answer? Maybe you said that it depends on the risk aversion of your friend or how much short-sightedness is affecting life quality. If so, you have committed a logical fallacy like most people do when evaluating risks. Scientific knowledge (here the risk of the operation) is useless unless you actually know how to use this information in taking rational decisions. You are using absolute risk instead of relative risk.

If you decide not to have LASIK, you must follow an alternative. Not having LASIK means either wearing no glasses, glasses, or contact lenses. Most people who opt for LASIK are wearing contact lenses. I looked up the following risks: 1 in 100 contact lense wearer risks a severe eye infection within 10 years. I read a story where this macrobe was eating out the

Parrots of our culture

I wrote this piece for a newspaper:

How old is the universe? I like to ask this question to non-scientists to tease out in which kind of the world they think they are living.   

The most interesting answer was from a Baptist priest sitting next to me on a trans-Atlantic flight to San Diego: 4000 years! I was a bit shocked as I have never met one of them. I politely asked him to explain the fossil finds in deep geological layers that are millions of years old. He quickly and confidently replied: Ah, that's the greatness of God. He made it all look as if it were millions of years old! To which I had no reply, because the man was logically consistent. If you assume an all mighty God, he could just about do that! Of course, such a theory does not explain why

Unexplained is not unexplicable

I swear I put the key on the table. I cannot explain to myself where it has gone. Only a ghost could explain its disappearance. But then I realised that the cat had stolen it. The theory of evolution on the species has no good explanations for the existence of certain organisms or biological phenomena in nature, therefore the evolution theory is wrong or incomplete. But could we not find an explanation in five or ten years?

The absence of an argument supporting a statement does not imply that no such argument exists or will be found in the future. An unexplained phenomena does not mean that it is unexplicable.

Stick with the dogma that all phenomena have explanations, even if they are currently unexplained.

Write down 5 examples where an unexplained phenomena could be interpreted as an inexplicable event.

Reliance on authority: pro and con

Everyone gets statements wrong from time to time. A professor might well be proven wrong by his student. And if a small child says that 1+1=2 and Einstein says it is not, then the small child is right. The truthfullness of a statement should never be judged by the authority of the proposer but only by the strength of the arguments supporting the statement.

However, if Jimmy has got his facts wrong several times and Jane has not, I will rather trust Jane on a future issue. And I rather trust the professor than the high school student to get his statements correct. Thus, a statement is more likely to be true if the proposer is viewed as an authority. Such a short-cut in thinking saves an enormous amount of thinking time but is not without risk.

The secret is to obessively disregard any authority when deciding on the truthfullness of a statement, but at the same time to develop an intuition on who you can trust to get their statement right, use their statements as working statements, and only later view the strength of the arguments supporting the statements.

Write down 10 aspects that makes someone an authority that you could trust.

Problems and Mysteries

We try to understand how things work by asking questions: Why does the moon circle around the earth? Why do men find younger women more attractive? Why does this politician get the most votes? Why does my neighbour have an affair? What is consciousness? Do we have freedom of mind?

Here is what Steven Pinker writes in How the Mind Works:

"The linguist Noam Chomsky once suggested that our ignorance can be divided into problems and mysteries. When we face a problem, we may not know its solution, but we have insight, increasing knowledge, an an inkling of what we are looking for. When we face a mystery, however, we can only stare in wonder and bewilderment, not knowing what an explanation would even look like."

Write down 10 problems and 10 mysteries. Remember some questions might be mysteries for some, problems for others, or even answered.

We could be both right or wrong

You argue that a liberal drug policy would reduce the number of drug users, because criminals have no incentives to recruit new addicts. Your friend argues that such a policy would lead to a huge increase in drug users, because drugs are freely available. Who is right? Then you dig out the statistics of the Netherlands, a country with a very liberal drug policy, and show your friend that drug use has not increased. You proved him wrong. And claim a win on the debate. But then you re-examine the data and see that the drug use stayed relatively constant defying your argument, too. You were both wrong. Or wait maybe you were both right, because the two effects might balance out?

When two people present statements, there are four scenarios. A is right, B is wrong. A is wrong, and B is right. And both A and B are right, and both A and B are wrong! Often, we get confused, because assume that the two statements are exactly opposite, e.g policy reduces number, or policy does NOT reduce number. However, very often both people hold different opinions but not 100% opposite opinions. You argued that drug use would go down, and your friend that it would go up. In fact, you were both wrong, drug use stayed relatively stable!

Never think that you have won an argument by defeating someone else's arguments. Sure, you have proven them wrong, but your statement could well be wrong or right.