What rights do people have, and are they ever absolute? Is liberty an end in itself? How much freedom should people have? Is utilitarianism a viable theory of justice? Political philosophy addresses questions that at first glance may seem obvious, but soon turn complex — is slavery always wrong? Is voluntary slavery therefore impossible? Questions like these are necessary, as Brennan explains, if we are to evaluate institutions as just or unjust. Social sciences may be able to inform us of some of the trade-offs and consequences of institutions, but they can’t tell us how to evaluate those trade-offs. “Is it better to be equal but worse off, or is it better to be unequal but better off? To answer that question, we have to think critically about justice,” Brennan writes. “We’ll have to know how to weigh equality against freedom or prosperity.”
Brennan’s work offers a short primer on the basic ideas of political philosophy, outlining the arguments of John Stuart Mill, John Locke, Jean- Jacques Rousseau, John Rawls, Robert Nozick, and many others. He also hosts the second Guide for Cato’s Libertarianism.org, a new series of online courses introducing the principles of libertarian thought. Political Philosophy serves as the accompanying text for his lectures, a series of short videos that can be watched online or downloaded for listening on the go.
Brennan’s Introduction focuses especially on libertarian philosophers and evaluates the various theories discussed, but does not aim to convince the reader of any particular ideology. Instead, Brennan provides readers with a broad working knowledge of political philosophy and the tools to think critically about these issues on their own.