It is said that Cambridge astrophysicist, Arthur Eddington thought that, in the early 1920s, there were only two people who really understood relativity: Einstein – and Arthur Eddington. He held the Plumian Chair of Astronomy and Experimental Philosophy for over 30 years, yet Einstein was doubtful about some of Eddington's own scholarly abilities, and commented in a letter in 1949 to Ilse Rosenthal-Schneider:
"I find that as a rule he was curiously uncritical about his own ideas."
He is not alone. Far too many people lack this curiosity today – and, sadly, I do not exclude myself from that long list. Eddington was capable of both profound and wacky thought (he's not alone there either); here's one of the former sort, from New Pathways in Science (1935):
"I hope I shall not shock the experimental physicists too much if I add that it is also a good rule not to put over-much confidence in the observervational results that are put forward until they have been confirmed by theory"