Picking rules

In "A Theory of Justice" by John Rawls, a thought experiment called the "Veil of Ignorance" is used to try to determine fair moral standards.  The gist of it is this:

• How would you structure society, if you didn't know in advance who you'd be?  

This simple question has forced many people to re-evaluate their positions and their prejudices.  How would you change laws, norms, and morality?  Considerations include gender, race, taxes, and treatment of criminals - many of whom have at least one mental disability, given them by nature.  Thoughts?