What is "justice" and why should we think about it?'

Justice on Wikipedia.

What is the difference between “equal justice” and “social justice”? What is the difference between “charity” and “social justice”? What is “personal property”? What is eminent domain? How much of what you earn is really yours? Who has the right to tell you what you can do with “your” property. What is the difference between “social justice” and “personal responsibility”? What is the difference between “social justice” and “free-market capitalism”? Is the United States based on a free market or on social justice? What was the purpose of the second amendment? Can you define what justice is? Does might make right? At what point does your neighbor’s obligations become your obligations? At what point is it fair for you to demand that someone else pay your bills and feed you and your family? At what point is it HIS responsibility to pay his bills and feed his family? What is poor? What is the American version of poor compared to Somalian version? At what point is the sacrifice and an American son or daughter justified to save the son or daughter of someone in a foreign nation?

These are just some thoughts that were bouncing around.