I've just been reading this article about somebody else flogging on the Drake equation for the x billionth time, and alot of things in the article really don't seem like science at all to me: http://news.bbc.co.uk/1/hi/sci/tech/7351428.stm
1st thing:The odds of intelligent life arising on another Earth-like planet are low, a British scientist has calculated.
oh really?, what piece of magnificent evidence did he glean from his sample size of one to come to that conclusion?The reason is that the "habitable lifespan" of an Earth-like planet - estimated at five billion years - will rarely be long enough for complex life to evolve.
25% is a short time now? Any confidence interval describing the length of time it takes for life to form on a habitable planet is going to have error margins way higher than a billion years :/the future life span of Earth will be "only" about another billion years - a short time compared to the four billion years since life first appeared on the planet.
But it's this that really gets my goat:
How did he calculate this probability? How how how? How in the name of [insert nonspecific deity] can anybody give statistical probabilities of events happening when your sample size is one?. It's absurd, it's beyond absurd; it's junk science. Scientists blithely churning out probabilities based on no more than a guess is what gives science a bad name and disillusions the public.Prof Watson identifies four - the emergence of single-celled bacteria; complex cells; specialised cells allowing complex life forms; intelligent life with an established language.
He estimates that the probability of each of these "critical steps" occurring in relation to the lifespan of Earth is no more than 10%.
So he's saying the probability of the Cambrian Explosion happening on a habitable planet is less than 10%. I mean, we don't even know how the cambrian explosion happened! A garden gnome sprouted in my yard; I don't know how it happened but I'm going to say the probability of it happening was 10%, because I say so...
This gets to the crux of it. He is practically making stuff up to get a PhD and parrot his supervisor's rare earth views."On the other hand, the rapid establishment of life on Earth after its formation may indicate that simple microbial life is relatively common."
Prof Watson completed his PhD under the supervision of James Lovelock, author of the Gaia hypothesis, "whose view of the earth as a whole system has influenced me ever since".
Why do so many astronomers have no integrity with regards to their statistics? I had to write a paper on extraterrestrial life last week and some of the junk I came across was astounding. Why do people use the Drake equation as a basis for some charade of an empirical investigation? It has more free parameters than an alcohol laden night with my housemates. As part of my degree I'm doing a 'life in space' module; to say is a joke would be flattering.
I know we have truly very little evidence on extraterrestrial life but that's no excuse for trying to use statistical methods when you have a sample size of 1. I could see the stupidity of that when I was 16, and yet people are getting PhDs awarded on the basis of this junk science.