What does "impossible" mean to you?

I was in my car today, running errands on a typical Sunday and found myself listening to one of my favorite songs that has the phrase, "impossible is not a word, it's just a reason not to try." Then, I started thinking...everything that we have in our world today is possible because of someone's idea or dream. Think about it and you know it's true. We have cars and airplanes because someone thought there should be a quicker way to travel. We have freezers and refridgerators because someone thought there ought to be a way to keep food fresh longer. We have oodles of technology because someone thought we could have something better than albums and pen and paper. The list goes on. The word, "possible" is defined as "can be, can exist, or can happen" and "impossible" is just the opposite. Here is where I get confused...how do we know what is impossible if we do not know what is possible? If you look at all of the progress society has made in the last 50 to 100 years, and asked someone that was born back then if they would've thought that what we currently would have been possible, you and I both know they would say, "no". We know that that is not true if those ideas, never conceived before, now exist and are now part of reality. Can you imagine what our world would be like if we all thought about what is possible first, instead of talking ourselves out of it because we think it is impossible? Martin Luther King Jr. never saw equal rights as impossible, even though it was difficult. Alexander Graham Bell never saw creating the telephone as impossible. The Wright Brothers knew we could fly, with the right calculations. Everything is possible. Failure does not guarantee that it is impossible. It just means that that one time didn't work; it doesn't mean that it won't work forever. You have to believe that it is possible. Everything can happen, can exist, but it starts with an idea or dream from you. Don't ever, ever, ever give up. Find a way to make it work and be willing to adapt to new alternatives and ideas. Keep trying...give it all you have...every time. All it takes is once...then it's possible.