Medieval Version: The "Commons" was land held communally by a village; each villager was expected to graze a "reasonable" number of sheep or cattle on the land at no expense to him.
|You don't overgraze||You overgraze|
|I don't overgraze||We both have enough to live on||You get rich; I still have enough to live on|
|I overgraze||I get rich; you still have enough to live on||The land is ruined by overgrazing and we both starve|
Twentieth Century Version: the "Population Explosion"
|You have 2.2 children||You have more than 2.2 children|
|I have 2.2 children||Stable or slowly declining population||Stable or slowly growing population|
|I have more than 2.2 children||Stable or slowly growing population||Population explosion; we all starve|
Twenty - First Century Version: the "Birth Dearth"
|You have children||You don't have children|
|I have children||Both our families pay for both our retirements||My kids have to pay for your retirement as well as mine|
|I don't have children||Your kids have to pay for my retirement as well as yours||Nobody pays for our retirement; we work till we drop, or starve.|