World From Top, By Klaus Lerdorf

• Freud
In response, Freud proposed that we do not move about in a common world, but a common thought process. He believed that all the actions of a person is motivated by one thing: lust. This led to numerous theories about reactionary consciousness.
• Other
Some philosophers, often inspired by David Lewis, argue that metaphysical concepts such as possibility, probability and necessity are best analyzed by comparing the world to a range of possible worlds; a view commonly known as modal realism.