A second theme running throughout the book is the theme of freedom. Freedom is an essential part of objectivism since objectivism finds its basis in capitalism. Capitalism is a system based on individual choice and individual rights. Man, who is distinguished from other life forms by the existence of his mind and ability to think, must use this ability to determine his own survival and existence. He must be based in rationality in order to function and this requires he is in a system based on individual rights.