What Is Philosophy?

Philosophy studies the fundamental nature of existence, of man, and of man’s relationship to existence. … In the realm of cognition, the special sciences are the trees, but philosophy is the soil which makes the forest possible.
—Ayn Rand, Philosophy, Who Needs It (p. 2)

A philosophy is a comprehensive system of ideas about human nature and the nature of the reality we live in. It is a guide for living, because the issues it addresses are basic and pervasive, determining the course we take in life and how we treat other people.

The topics that philosophy addresses fall into several distinct fields. Among those of fundamental concern are:

• Metaphysics (the theory of reality).
• Epistemology (the theory of knowledge)
• Ethics (the theory of moral values)
• Politics (the theory of legal rights and government)
• Aesthetics (the theory of the nature of art)

The most widespread systems of ideas that offer philosophical guidance are religions such as Buddhism, Christianity, Judaism, and Islam. Religions differ from philosophies not in the subjects they address, but in the method they use to address them. Religions have their basis in mythic stories that pre-date the discovery of explicitly rational methods of inquiry.

Many religions nowadays appeal to mystical faith and revelation—modes of belief that claim validity independent of logic and the scientific method, at least for the biggest questions. But most religions are in their origins pre-rational rather than anti-rational, a story-teller’s account of philosophic issues rather than a scientist’s.

In Greek, “philosophy” means “love of wisdom.” Philosophy is based on rational argument and appeal to facts. The history of the modern sciences begins with philosophical inquiries, and the scientific method of experimentation and proof remains an instance of the general approach that a philosopher tries to bring to a question: one that is logical and rigorous. However, while today the sciences focus on specialized inquiries in restricted domains, the questions addressed by philosophy remain the most general and most basic, the issues that underlie the sciences and stand at the base of a world-view.

Philosophy raises some of the deepest and widest questions there are. Addressing the issues in each branch of philosophy requires integrating everything one knows about reality (metaphysics) or humanity (epistemology, ethics, politics, and aesthetics). Proposing reasonable positions in philosophy is therefore a difficult task. Honest philosophers have often disagreed about key issues, and dishonest ones have been able to slip their own positions into the mix as well. For this reason, there is not one philosophy worldwide, as there is one physics. Instead, there are many philosophies.

Over the course of history, philosophers have offered entire systems that pulled together positions in each of the branches of philosophy. Aristotle, the father of logic, authored such a system in ancient times, teaching that we could know reality and achieve happiness. In more modern times, philosophers such as John Locke and Immanuel Kant have written systematic accounts of their thought.

Most modern philosophers, however, have specialized in one area or another within philosophy, although some schools of philosophy have emerged that are marked by the general positions of their members on a variety of issues and the members’ shared admiration for a chain of historical figures. These schools have included Pragmatism, Logical Positivism, and Existentialism, but are little-known outside of university classes in modern philosophy.

Today philosophic issues often enter public life through political or social movements, some religious in inspiration, such as Christian conservatism, and others secular, such as left-wing environmentalism and socialism. The ideas of such movements are often called ideologies. That term, “ideology,” is another name for the systems of ideas we have been talking about. Though the focus of ideological movements is political, their political beliefs tend to be rooted in shared conceptions of reality, human nature, and values.