What makes me the same person today that I was yesterday or will be tomorrow? In Plato's Symposium, Socrates observed that all of us are constantly undergoing change--physical as well as changes in our "manners, customs, opinions, desires, pleasures, pains, and] fears." Aristotle theorized that some underlying "substratum" remains constant even while we undergo these changes. John Locke rejected Aristotle's view and reformulated the problem of personal identity in his own way. These essays--written by prominent philosophers and legal and economic theorists--offer valuable insights into the...

Do environmental problems need government controls or can we find solutions by harnessing the incentives of the free market?