• I have argued flying saucers with lots of people. I was interested in possible. They do not appreciate that the problem is not to demonstrate whether it's possible or not but whether it's going on or not.

    Richard P. Feynman: I have argued flying saucers with lots of people. I was interested in possible. They do not appreciate that the problem is not to demonstrate whether it's possible or not but whether it's going on or not.