Even if the Kepler and COROT missions do find an abundance of planets, the Kantian revolution will not be complete. The new planets might be exactly the same size as Earth and orbit their stars at the same distance, and although an astronomer might be willing to call such a thing Earth-like, most people will look for more. Does it have liquid water? Does it have a recognizable atmosphere? And, inevitably, could it — does it — support life?I wonder whether Kant would regard the discovery that bacteria had once lived on Mars or might live elsewhere - if it is made - as evidence for his position.
Finding the answers to these questions will take decades. Kepler and COROT are merely steps along the way. In the meantime, we can take solace from Kant: "I am of the opinion that it is not particularly necessary to assert that all planets must be inhabited. However, at the same time it would be absurd to deny this claim with respect to all or even to most of them."
It took nearly 250 years to prove him mostly right the first time. With a little luck and perseverance — and, as Boss shows, a lot of work by astronomers around the world — the final step may just come a little faster.
Alfred Russel Wallace on why Mars is not habitable
See also: Boldly go, but why, exactly?Extraterrestrials:
Several million UFOs later - the state of the question
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Some scientists hope that the aliens are NOT out there!
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