If you don't know what can't be done, you set no limits. Roger Bannister is a great example. No one believed the mile could be run in as little as 4 minutes. And yet, Bannister accomplished precisely that back in the 50's. Once he had done it, no one ever again considered it impossible, and many people world-wide were able to replicate and even inprove on his effort.
No one believed there was anything smaller than the eye could see, and yet, when the modern microscope was invented, those who had not believed, realized they had been short-sighted.
When Jules Verne wrote his fantasy novels about traveling under the sea or flying to the moon, people dismissed them as novelistic imaginative creations of an over-active mind, and yet we all know now that there was nothing imaginary about it. If the Wright brothers or the inventors of the submarine had known that it was impossible to fly or if they had known that it was impossible to build a craft that could carry men below the sea, we would not even have seen the advent of flying and eventually space travel, nor of subacuatic maneuvers.
When Columbus convinced Isabella and Ferdinand of Spain to finance his ventures, despite the nay-sayers' conviction that he would merely fall off the edge of the world, when the medical world believe heart transplants would never work, and when people scoffed at Alexander Graham Bell's insistence that the voice could be carried over wires to another house, another city, another country, they did not realize that an element within the hearts and psyche of some members of the human family made them believe when all others did not, that it was better to not know what can't be done than to know what can't be done.
Todays' post was inspired by Henry Ford: I am looking for a lot of men who have an infinite capacity to not know what can't be done. That's how Ford invented the car (horse-less carriage) and went on to improve on the original design over and over again.
In which area of your life can you be adventurous enough to not know what can't be done?
A final point: when you are scoffing at that which has not yet been invented or found to be possible (think scanners à la Star Trek that immediately heal the body, think Demi Moore dancing with Patrick Swayze in Ghost, think Jodie Foster making contact in Contact, think parallel universes in Fringe, and the list could go on and on), so when you are getting ready to scoff at it all, remember all of the above ... all of it was scoffed at and yet all of it now exists.