[asa] Shermer and Inevitability

Michael Shermer makes an argument that doesn't strike me as being as strong as he thinks it is:

http://www.scientificamerican.com/article.cfm?id=will-e-t-look-like-us

Shermer writes:

"What are the odds that intelligent, technically advanced aliens would look anything like the ones in films, with an emaciated torso and limbs, spindly fingers and a bulbous, bald head with large, almond-shaped eyes? What are the odds that they would even be humanoid? In a YouTube video, produced by Josh Timonen of the Richard Dawkins Foundation for Reason and Science, I argue that the chances are close to zero"

and explains:

"if something like a smart, technological, bipedal humanoid has a certain level of inevitability because of how evolution unfolds, then it would have happened more than once here."

Not necessarily. If event X has the likelihood of happening once every 3 billion years, then after 3 billion years, it becomes inevitable and it happens once. It's like the lottery. If the odds of winning are a million-to-one, if a million people play, someone will win. That the winning is inevitable does not mean a thousand people from that million should win.

Shermer also adds:

"But of the 60 to 80 phyla of animals, only one, the chordates, led to intelligence, and only the vertebrates actually developed it. Of all the vertebrates, only mammals evolved brains big enough for higher intelligence. And of the 24 orders of mammals only one-ours, the primates-has technological intelligence. As the late Harvard evolutionary biologist Ernst Mayr concluded: "Nothing demonstrates the improbability of the origin of high intelligence better than the millions of phyletic lineages that failed to achieve it." In fact, Mayr calculated that even though there have evolved perhaps as many as 50 billion species on Earth, "only one of these achieved the kind of intelligence needed to establish a civilization.""

But this is like arguing that since there was only one winner of the lottery, it was not inevitable that someone, somewhere would win. Yet if enough people play, it becomes more likely that someone will win to the point that it becomes inevitable. And the more people that play, the more people who do not win.

Inevitability does not mean an event should happen multiple times. It would depend on how likely that event was. And unless we have independent evidence about this probability, we cannot rule out inevitability because the event happened once.

Mike

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Received on Fri Nov 6 21:22:26 2009