We put all sorts of artificial limits on ourselves that are based more in cultural assumption than in truth.
What if the Wright brothers had listened to the people who said, "If God had intended people to fly, He would have given us wings?" These two men, who ran a bicycle shop, defied the conventional wisdom and today the air is filled with people.
I remember in 1957, when the Soviet Union launched the first satellite. They had such a head start that everyone assumed Russia would dominate outer space from then on. Three years later President John F. Kennedy, here at Rice University, challenged America to put a human being on the moon by the end of the decade. On July 20, 1969, Neil Armstrong stepped off the Eagle Lander on to the moon: "One small step for man; one giant leap for mankind," he said.
Never accept the limits others put on you.