Jon Kågström

There is a 95% chance of human extinction before 11126 AD and what is even worse, the tiny probability of 0.01% for me to find a date tonight. At least if we agree to trust Bayesian statistics.

The Doomsday Argument (Brandon Carter, 1983) predicts the human extinction by first assuming with a certainty of 95% that we are among the last 95% of humans to ever be born. Then, by using an estimate of how many humans have been born so far it is possible to obtain the expected total number of born humans on the doomsday. This is done under the assumption that the world population stabilises at 10 billion with a life expectancy of 80 years. On these and more assumptions it is derived that there is a 95% chance of human extinction within 9120 years.

This can of course be worrying if you plan to reincarnate or live a very long healthy life. What is more worrying at the moment is my slight chance of finding a date – tonight. Again Bayesian statistics have found a new ground – the probability to successfully pull (flirt), namely the pullability. The pullability, exactly as the Doomsday Argument, is based on a number of assumptions and generalizations.

The pullability is obtained from a set of parameters you submit about yourself. Examples of parameters are your height, weight, dance skills, self confidence, biceps circumference, time since last shower etc. Truthfully I entered all my parameters and clicked on the “submit” button. Without knowing what to expect, a message showed

Jon your pullability is 0.000108768689858. This theoretically means that you have about a 0.01% chance of pulling!

First I smiled and dismissed it as nonsense, only to realize that it is probably quite accurate.

The Doomsday Argument is controversial; intellectuals provide a great arsenal of critique and objections. However, none has been able to refute the Doomsday Argument. Accepting Bayesian statistics can be hard as probabilities are subjective or as most classical frequentist consider them, muddled. I tag along with Bayesian followers even though it hammers me with a pullability of 0.01%. Perhaps that is what opponents fear. Not only will they have to accept that there is a 95% chance of extinction within 9120 years, they also have to face their pullability.

I am off to the pub. Wish me luck. I evidently need it.

This entry was posted on Thursday, July 12th, 2007 at 6:45 am and is filed under Uncategorized. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.