A new life form found

Source: The Straits Times, 4 December 2010, p.A18
Headline: Bacterium in US lake unlike any other known life form

Quote1
WASHINGTON: All life on Earth ... requires the element phosphorus as one of its six essential components. But now researchers have uncovered a bacterium that ... has replaced phosphorus with its toxic cousin, arsenic. "What we've found is a microbe doing something new," said scientist Felisa Wolfe-Simon, ... who made the ground-breaking discovery at California's Mono Lake. ... "We've cracked open the door to what's possible for life elsewhere in the universe. And that's profound," [said Dr Wolfe-Simon]. ...

Comment1
A single incident of X is sufficient to prove that X is possible -- because it has happened. A single incident on earth implies nothing for the rest of the universe. It is not profound.

Quote2
Theoretical physicist and cosmologist Paul Davies [said]: "It defies logic to think she [Dr Wolfe-Simon] found the only example of this kind of unusual life. Quite clearly, this is the tip of a huge iceberg." ...

Comment2
Someone enters a darkened room 1,000 times and each time emerges with a white ball. These experiences lead him to declare that all balls are white. On the 1,001st expedition into the darkened room, he emerges with a black ball. It is logical to then declare: "A ball is possibly black." It is not logical therefrom to declare: "There is here a roomful of black balls." Doing that would commit the Fallacy of Hasty Generalisation.

Quote3
The discovery could also have a major impact on space missions to Mars and elsewhere looking for life. The experiments on such missions are designed to ferret out the handful of chemical elements and reactions that have been known to characterise life on earth. Scientists are now asking if the searches should be widened. -- Washington Post, AFP, NYT.

Comment3
Up until this discovery, all life on earth has had six essential components, including phosphorus. From this observation, we concluded that these six components are necessary for life, even equivalent to life -- which is why the hunt for extra-terrestrial life involved searching for these "elements and reactions". This new discovery presents one instance of one element (phosphorus) being not necessary. The necessity of the other five components is still intact. Hence, any widening should go only as far as to include arsenic as a seventh essential component. No further.

END