Consider life in a small medival town. Of the many economic activities that take place in the town one of the most important is raising sheep. Many of the town’s families own flocks of sheep and support themselves by selling the sheep’s wool which is used to make clothing. As our story begins the sheep spend much of their time grazing on the land surrounding the town called the Town Common. No family owns the land. Instead the town residents own of the land collectively and all the residents are allowed to graze their sheep on it. Collective ownership works well because land is plentiful. As long as everyone can get all the good grazing land they want the town Common is not rival in consumption and allowing residents sheep to graze for free causes no problems. Everyone in town is happy. As the years pass the population of the town grows and so does the number of sheep grazing on the Town common. With a growing number of sheep and a fixed amount ...