19 August 2009

A Governor’s prayer for rain

I just received an email from Michael Schermer's e-skeptic about a method used in Atlanta, GA, to produce rain in a period of drought in 2007:
On Tuesday, November 13, 2007, Sonny Perdue, the Governor of Georgia, led a group of approximately 250 persons, including many state officials, in a prayer for rain on the steps of the state capitol in Atlanta. Georgia had been suffering an extreme drought, and the level of Lake Lanier, an important water reservoir near Atlanta, had been decreasing dramatically over several months. Governor Perdue believed that a divine intervention was necessary and so he boldly asked God to bring rain. Fully expecting his prayer to be effective, Perdue said “Hopefully we will be better conservators of the blessings God’s given us as he gives us more [rain].”
There is no need to discuss further the idiocy of such an act. But (miracle of miracles!) ....
the next day there was light rain in Atlanta and much rain came to the area over the next couple of months. Many Georgians considered Perdue a hero and thought that his prayer had influenced God to increase rainfall to the drought stricken vicinity of Atlanta.

So, the e-skeptic people decided to conduct a
[statistical] investigation to determine whether the prayer was correlated with an increase in rain, and if so, how likely it was to have caused the increase.
And guess what they found:
However, no evidence was found for a causal relationship between the prayer and the increase in rain. The Governor did not produce the increase, despite the claims of many that he did! This is clear from comparing the outcome of his day of prayer to the outcomes of nonprayer days. Nonprayer days were likely to be followed by rainfall increases equal to or greater than what followed the Governor’s prayer day approximately 11% of the time for all nonprayer days, 17% of the time for nonprayer days in November, and 50% of the time for nonprayer days preceded by periods of low rainfall. Any belief that the Governor produced an increase in rain by his prayer on November 13, 2007 can be considered to be wishful thinking.
It is sad that there are so many idiots who are ready to believe that there is a causal relationshop between prayer and rainfall. It is also equally sad that we have to run scientific experiments to prove (to these idiots) the obvious. But guess what: no matter what proof you give (to these idiots), these people will remain unconvinced. Faith is more powerful (for them) than proof.

Watch the following video (about a minute after the start) to hear what the moron Governor says:

Here is a little problem... WHICH God did this moron (and the idiots who prayed along) pray to? Some prayed to Allah, some to Zeus, some to other gods. Do gods of different religions collaborate to answe the prayer, to produce the rain? Hm... probably not. This simple thought alone should be enough to spare e-skeptic from conducting a scientific experiment to prove the obvious.

It seems that many politicians act completely irrationally, by appealing to "gods", to "prayers" and to "faith". I commented on one of them earlier. And it would be OK as long as they did so for their own private reasons. Nevertheless, they do use "gods", "prayers" and "faith" in order to take decisions that affect peoples' lives. (Remember that Bush invaded Iraq because "god told him so"?) This IS the problem.

4 August 2009

An Einstein quote

The world is not dangerous because of those who do harm but because of those who look at it without doing anything.


What measure theory is about

It's about counting, but when things get too large.
Put otherwise, it's about addition of positive numbers, but when these numbers are far too many.

The principle of dynamic programming

max_{x,y} [f(x) + g(x,y)] = max_x [f(x) + max_y g(x,y)]

The bottom line

Nuestras horas son minutos cuando esperamos saber y siglos cuando sabemos lo que se puede aprender.
(Our hours are minutes when we wait to learn and centuries when we know what is to be learnt.) --António Machado

Αγεωμέτρητος μηδείς εισίτω.
(Those who do not know geometry may not enter.) --Plato

Sapere Aude! Habe Muth, dich deines eigenen Verstandes zu bedienen!
(Dare to know! Have courage to use your own reason!) --Kant