Philosophy (from Greek φιλοσοφία, philosophia, literally "love of wisdom") is the study of general and fundamental problems concerning matters such as existence, knowledge, values, reason, mind, and language. The term was probably coined by Pythagoras (c. 570 – c. 495 BC). Philosophical methods include questioning, critical discussion, rational argument and systematic presentation. Classic philosophical questions include: Is it possible to know anything and to prove it? What is most real? However, philosophers might also pose more practical and concrete questions such as: Is there a best way to live? Is it better to be just or unjust (if one can get away with it)? Do humans have free will?
Historically, "philosophy" encompassed any body of knowledge. From the time of Ancient Greek philosopher Aristotle to the 19th century, "natural philosophy" encompassed astronomy, medicine and physics. For example, Newton's 1687 Mathematical Principles of Natural Philosophy later became classified as a book of physics. In the 19th century, the growth of modern research universities led academic philosophy and other disciplines to professionalize and specialize. In the modern era, some investigations that were traditionally part of philosophy became separate academic disciplines, including psychology, sociology, linguistics and economics.
Other investigations closely related to art, science, politics, or other pursuits remained part of philosophy. For example, is beauty objective or subjective? Are there many scientific methods or just one? Is political utopia a hopeful dream or hopeless fantasy? Major sub-fields of academic philosophy include metaphysics ("concerned with the fundamental nature of reality and being"), epistemology (about the "nature and grounds of knowledge [and]...its limits and validity" ), ethics, aesthetics, political philosophy, logic, philosophy of science and the history of Western philosophy.
Since the 20th century professional philosophers contribute to society primarily as professors, researchers and writers. However, many of those who study philosophy in undergraduate or graduate programs contribute in the fields of law, journalism, politics, religion, science, business and various art and entertainment activities.
Traditionally, the term "philosophy" referred to any body of knowledge. In this sense, philosophy is closely related to religion, mathematics, natural science, education and politics. Newton's 1687 "Mathematical Principles of Natural Philosophy" is classified in the 2000s as a book of physics; he used the term "natural philosophy" because it used to encompass disciplines that later became associated with sciences such as astronomy, medicine and physics.
Philosophy was traditionally divided into three major branches:
- Natural philosophy ("physics") was the study of the physical world (physis, lit: nature);
- Moral philosophy ("ethics") was the study of goodness, right and wrong, beauty, justice and virtue (ethos, lit: custom);
- Metaphysical philosophy ("logos") was the study of existence, causation, God, logic, forms and other abstract objects ("meta-physika" lit: "what comes after physics").
This division is not obsolete but has changed. Natural philosophy has split into the various natural sciences, especially astronomy, physics, chemistry, biology and cosmology. Moral philosophy has birthed the social sciences, but still includes value theory (including aesthetics, ethics, political philosophy, etc.). Metaphysical philosophy has birthed formal sciences such as logic, mathematics and philosophy of science, but still includes epistemology, cosmology and others.
Many philosophical debates that began in ancient times are still debated today. Colin McGinn and others claim that no philosophical progress has occurred during that interval. Chalmers and others, by contrast, see progress in philosophy similar to that in science, while Talbot Brewer argued that "progress" is the wrong standard by which to judge philosophical activity.
In one general sense, philosophy is associated with wisdom, intellectual culture and a search for knowledge. In that sense, all cultures and literate societies ask philosophical questions such as "how are we to live" and "what is the nature of reality". A broad and impartial conception of philosophy then, finds a reasoned inquiry into such matters as reality, morality and life in all world civilizations.
Western philosophy is the philosophical tradition of the Western world and dates to Pre-Socratic thinkers who were active in Ancient Greece in the 6th century BC such as Thales (c. 624 – c. 546 BC) and Pythagoras (c. 570 – c. 495 BC) who practiced a "love of wisdom" (philosophia) and were also termed physiologoi (students of physis, or nature). Socrates was a very influential philosopher, who insisted that he possessed no wisdom but was a pursuer of wisdom. Western philosophy can be divided into three eras: Ancient (Greco-Roman), Medieval philosophy (Christian European), and Modern philosophy.
The Ancient era was dominated by Greek philosophical schools which arose out of the various pupils of Socrates, such as Plato who founded the Platonic Academy, and was one of the most influential Greek thinkers for the whole of Western thought. Plato's student Aristotle was also extremely influential, founding the Peripatetic school. Other traditions include Cynicism, Stoicism, Greek Skepticism and Epicureanism. Important topics covered by the Greeks included metaphysics (with competing theories such as atomism and monism), cosmology, the nature of the well-lived life (eudaimonia), the possibility of knowledge and the nature of reason (logos). With the rise of the Roman empire, Greek philosophy was also increasingly discussed in Latin by Romans such as Cicero and Seneca.
Medieval philosophy (5th – 16th century) is the period following the fall of the Roman empire and was dominated by the rise of Christianity and hence reflects Judeo-Christian theological concerns as well as retaining a continuity with Greco-Roman thought. Problems such as the existence and nature of God, the nature of faith and reason, metaphysics, the problem of evil were discussed in this period. Some key Medieval thinkers include St. Augustine, Thomas Aquinas, Boethius, Anselm and Roger Bacon. Philosophy for these thinkers was viewed as an aid to Theology (ancilla theologiae) and hence they sought to align their philosophy with their interpretation of sacred scripture. This period saw the development of Scholasticism, a text critical method developed in medieval universities based on close reading and disputation on key texts. The Renaissance (1355–1650) period saw increasing focus on classic Greco-Roman thought and on a robust Humanism.
Early modern philosophy in the Western world begins with thinkers such as Thomas Hobbes and René Descartes (1596–1650). Following the rise of natural science, Modern philosophy was concerned with developing a secular and rational foundation for knowledge and moved away from traditional structures of authority such as religion, scholastic thought and the Church. Major modern philosophers include Spinoza, Leibniz, Locke, Berkeley, Hume, and Kant. 19th-century philosophy is influenced by the wider movement termed the Enlightenment, and includes figures such as Hegel a key figure in German idealism, Nietzsche a famed anti-Christian, J.S. Mill who promoted Utilitarianism, Karl Marx who developed the foundations for Communism and the American William James. The 20th century saw the split between Analytic philosophy and Continental philosophy, as well as philosophical trends such as Phenomenology, Existentialism, Logical Positivism, Pragmatism and the Linguistic turn.