This just in from the New York Times. Today's scientists were asked what they continue to believe in despite being able to prove it.
"God (or Not), Physics and, of Course, Love: Scientists Take a Leap"
The New York Times > Science > God (or Not), Physics and, of Course, Love: Scientists Take a Leap: "Kenneth Ford
Physicist; retired director, American Institute of Physics; author, 'The Quantum World'
I believe that microbial life exists elsewhere in our galaxy.
I am not even saying 'elsewhere in the universe.' If the proposition I believe to be true is to be proved true within a generation or two, I had better limit it to our own galaxy. I will bet on its truth there.
I believe in the existence of life elsewhere because chemistry seems to be so life-striving and because life, once created, propagates itself in every possible direction. Earth's history suggests that chemicals get busy and create life given any old mix of substances that includes a bit of water, and given practically any old source of energy; further, that life, once created, spreads into every nook and cranny over a wide range of temperature, acidity, pressure, light level and so on.
Believing in the existence of intelligent life elsewhere in the galaxy is another matter."