Philosophers and philosophically-inclined politician, clergyman and writers have shaped the American intellect by thinking and reflecting on a great variety of topics: on the Constitution, on political struggles, on the nation itself, on religion, on psychology and on how to live. The term American philosophy tends to cover both philosophy done in America, by Americans and about the United States.
Well-known American philosophers from the nineteenth century include the Pragmatists: Charles Sanders Peirce, William James and John Dewey. James applied the Pragmatist philosophy to understanding psychology and specifically the psychology of religious belief (in his famous Varieties of Religious Experience), while Dewey was famous for his influence on progressive politics and on developing progressive theories of education.
In the twentieth century, many American philosophers were involved in the project of analytic philosophy with their English counterparts, as well as philosophers fleeing to Britain and the U.S. due to the rise of Adolf Hitler in Germany. A comprehensive list of these is tremendously long, but would include Willard van Orman Quine, Saul Kripke, David Kellogg Lewis, Thomas Kuhn, Alvin Plantinga, John Searle, Daniel Dennett, Hilary Putnam, Donald Davidson, Thomas Nagel, Edmund Gettier, Alvin Goldman and Robert Nozick.
In addition, the revival of political philosophy in the twentieth century was primarily led by American philosophers: John Rawls' A Theory of Justice, and the libertarian response Anarchy, State and Utopia by Robert Nozick still dominate the field. American philosophers have also developed communitarian responses to liberalism: Alisdair MacIntyre (though Scottish-born, MacIntyre has lived a large amount of his career in the US), Michael Sandel (in Liberalism and the Limits of Justice), the Canadian philosopher Charles Taylor and Michael Walzer.
In popular society (especially among libertarians), the philosophy of Objectivism as initially described by the USSR-emigrant novelist Ayn Rand has become popular, including with former Federal Reserve chairman Alan Greenspan. Academic philosophers widely consider Ayn Rand to be a figure of only marginal interest.