In his State of the Union address, President Barack Obama talked about Americans paying their fair share in taxes. For most of my life, I thought that I had a reasonably good idea about what "fair" means — except for that period when my children were young and "fair" meant getting precisely what they wanted, when they wanted it, and if they didn't get it instantly it was "not fair." The meaning of the word became especially tricky when each of my children wanted something different. How could something be fair to one and "not fair" to the others? Shouldn't fairness be something that takes into consideration the needs and desires of all of them, as well as my wife and me?