Philosophy (from Greek ?????????, 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. 570-495 BCE). 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? Philosophers 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.
In Classical antiquity, Philosophy was traditionally divided into three major branches:
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 BCE such as Thales (c. 624-546 BCE) and Pythagoras (c. 570-495 BCE) 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 western 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, Kierkegaard who developed the foundations for existentialism, 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.
The regions of the fertile Crescent, Iran and Arabia are home to the earliest known philosophical Wisdom literature and is today mostly dominated by Islamic culture. Early wisdom literature from the fertile crescent was a genre which sought to instruct people on ethical action, practical living and virtue through stories and proverbs. In Ancient Egypt, these texts were known as sebayt ('teachings') and they are central to our understandings of Ancient Egyptian philosophy. Babylonian astronomy also included much philosophical speculations about cosmology which may have influenced the Ancient Greeks. Jewish philosophy and Christian philosophy are religio-philosophical traditions that developed both in the Middle East and in Europe, which both share certain early Judaic texts (mainly the Tanakh) and monotheistic beliefs. Jewish thinkers such as the Geonim of the Talmudic Academies in Babylonia and Maimonides engaged with Greek and Islamic philosophy. Later Jewish philosophy came under strong Western intellectual influences and includes the works of Moses Mendelssohn who ushered in the Haskalah (the Jewish Enlightenment), Jewish existentialism and Reform Judaism.
Pre-Islamic Iranian philosophy begins with the work of Zoroaster, one of the first promoters of monotheism and of the dualism between good and evil. This dualistic cosmogony influenced later Iranian developments such as Manichaeism, Mazdakism, and Zurvanism.
After the Muslim conquests, Early Islamic philosophy developed the Greek philosophical traditions in new innovative directions. This Islamic Golden Age influenced European intellectual developments. The two main currents of early Islamic thought are Kalam which focuses on Islamic theology and Falsafa which was based on Aristotelianism and Neoplatonism. The work of Aristotle was very influential among the falsafa such as al-Kindi (9th century), Avicenna (980 - June 1037) and Averroes (12th century). Others such as Al-Ghazali were highly critical of the methods of the Aristotelian falsafa. Islamic thinkers also developed a scientific method, experimental medicine, a theory of optics and a legal philosophy. Ibn Khaldun was an influential thinker in philosophy of history.
In Iran several schools of Islamic philosophy continued to flourish after the Golden Age and include currents such as Illuminationist philosophy, Sufi philosophy, and Transcendent theosophy. The 19th and 20th century Arab world saw the Nahda (awakening or renaissance) movement which influenced contemporary Islamic philosophy.
Indian philosophy (Sanskrit: dar?ana; 'world views', 'teachings') are philosophical traditions originating in the Indian subcontinent. Traditions of Indian philosophy are generally classified as either orthodox or heterodox - ?stika or n?stika - depending on whether they accept the authority of the Vedas and whether they accept the theories of Brahman and Atman. The orthodox schools generally include Nyaya, Vaisheshika, Samkhya, Yoga, M?m??s? and Vedanta, and the common heterodox schools are Jain, Buddhist, Ajñana, Ajivika and C?rv?ka. Some of the earliest surviving philosophical texts are the Upanishads of the later Vedic period (1000-500 BCE). Important Indian philosophical concepts include dharma, karma, samsara, moksha and ahimsa. Indian philosophers developed a system of epistemological reasoning (pramana) and logic and investigated topics such as metaphysics, ethics, hermeneutics and soteriology. Indian philosophy also covered topics such as political philosophy as seen in the Arthashastra c. 4th century BCE and the philosophy of love as seen in the Kama Sutra.
The commonly named six orthodox schools arose sometime between the start of the Common Era and the Gupta Empire. These Hindu schools developed what has been called the "Hindu synthesis" merging orthodox Brahmanical and unorthodox elements from Buddhism and Jainism as a way to respond to the unorthodox challenges. Hindu thought also spread east to the Indonesian Srivijaya empire and the Cambodian Khmer Empire.
Later developments include the development of Tantra and Iranian-Islamic influences. Buddhism mostly disappeared from India after the Muslim conquest in the Indian subcontinent, surviving in the Himalayan regions and south India. The early modern period saw the flourishing of Navya-Ny?ya (the 'new reason') under philosophers such as Raghunatha Siromani (c.1460-1540) who founded the tradition, Jayarama Pancanana, Mahadeva Punatamakara and Yashovijaya (who formulated a Jain response).
The modern era saw the rise of Hindu nationalism, Hindu reform movements and Neo-Vedanta (or Hindu modernism) whose major proponents included Vivekananda, Mahatma Gandhi and Aurobindo and who for the first time promoted the idea of a unified "Hinduism". Due to the influence of British colonialism, much modern Indian philosophical work was in English and includes thinkers such as Radhakrishnan, Krishna Chandra Bhattacharya, Bimal Krishna Matilal and M. Hiriyanna.
Buddhist philosophy begins with the thought of Gautama Buddha (fl. between sixth and fourth centuries BCE) and is preserved in the early Buddhist texts. Buddhist thought is trans-regional and trans-cultural. It originated in India and later spread to East Asia, Tibet, Central Asia, and Southeast Asia, developing new and syncretic traditions in these different regions. The various Buddhist schools of thought are the dominant philosophical tradition in Tibet and Southeast Asian countries like Sri Lanka and Burma. Because ignorance to the true nature of things is considered one of the roots of suffering (dukkha), Buddhist philosophy is concerned with epistemology, metaphysics, ethics and psychology. The ending of dukkha also encompasses meditative practices. Key innovative concepts include the Four Noble Truths, Anatta (not-self) a critique of a fixed personal identity, the transience of all things (Anicca), and a certain skepticism about metaphysical questions.
Later Buddhist philosophical traditions developed complex phenomenological psychologies termed 'Abhidharma'. Mahayana philosophers such as Nagarjuna and Vasubandhu developed the theories of Shunyata (emptiness of all phenomena) and Vijnapti-matra (appearance only), a form of phenomenology or transcendental idealism. The Dign?ga school of Pram??a promoted a complex form of epistemology and Buddhist logic. After the disappearance of Buddhism from India, these philosophical traditions continued to develop in the Tibetan Buddhist, East Asian Buddhist and Theravada Buddhist traditions. The modern period saw the rise of Buddhist modernism and Humanistic Buddhism under Western influences and the development of a Western Buddhism with influences from modern psychology and Western philosophy.
East Asian philosophical thought began in Ancient China, and Chinese philosophy begins during the Western Zhou Dynasty and the following periods after its fall when the "Hundred Schools of Thought" flourished (6th century to 221 BCE). This period was characterized by significant intellectual and cultural developments and saw the rise of the major philosophical schools of China, Confucianism, Legalism, and Daoism as well as numerous other less influential schools. These philosophical traditions developed metaphysical, political and ethical theories such Tao, Yin and yang, Ren and Li which, along with Chinese Buddhism, directly influenced Korean philosophy, Vietnamese philosophy and Japanese philosophy (which also includes the native Shinto tradition). Buddhism began arriving in China during the Han Dynasty (206 BCE-220 CE), through a gradual Silk road transmission and through native influences developed distinct Chinese forms (such as Chan/Zen) which spread throughout the East Asian cultural sphere. During later Chinese dynasties like the Ming Dynasty (1368-1644) as well as in the Korean Joseon dynasty (1392-1897) a resurgent Neo-Confucianism led by thinkers such as Wang Yangming (1472-1529) became the dominant school of thought, and was promoted by the imperial state.
In the Modern era, Chinese thinkers incorporated ideas from Western philosophy. Chinese Marxist philosophy developed under the influence of Mao Zedong, while a Chinese pragmatism under Hu Shih and New Confucianism's rise was influenced by Xiong Shili. Modern Japanese thought meanwhile developed under strong Western influences such as the study of Western Sciences (Rangaku) and the modernist Meirokusha intellectual society which drew from European enlightenment thought. The 20th century saw the rise of State Shinto and also Japanese nationalism. The Kyoto School, an influential and unique Japanese philosophical school developed from Western phenomenology and Medieval Japanese Buddhist philosophy such as that of Dogen.
African philosophy is philosophy produced by African people, philosophy that presents African worldviews, ideas and themes, or philosophy that uses distinct African philosophical methods. Modern African thought has been occupied with Ethnophilosophy, with defining the very meaning of African philosophy and its unique characteristics and what it means to be African. During the 17th century, Ethiopian philosophy developed a robust literary tradition as exemplified by Zera Yacob. Another early African philosopher was Anton Wilhelm Amo (c. 1703-1759) who became a respected philosopher in Germany. Distinct African philosophical ideas include Ujamaa, the Bantu idea of 'Force', Négritude, Pan-Africanism and Ubuntu. Contemporary African thought has also seen the development of Professional philosophy and of Africana philosophy, the philosophical literature of the African diaspora which includes currents such as black existentialism by African-Americans. Modern African thinkers have been influenced by Marxism, African-American literature, Critical theory, Critical race theory, Postcolonialism and Feminism.
Indigenous American philosophy is the philosophy of the Indigenous people of the Americas. There is a wide variety of beliefs and traditions among these different American cultures. Among some of the Native Americans in the United States there is a belief in a metaphysical principle called the "Great Mystery" (Siouan: Wakan Tanka, Algonquian: Gitche Manitou). Another widely shared concept was that of Orenda or "spiritual power". According to Peter M. Whiteley, for the Native Americans, "Mind is critically informed by transcendental experience (dreams, visions and so on) as well as by reason." The practices to access these transcendental experiences are termed Shamanism. Another feature of the indigenous American worldviews was their extension of ethics to non-human animals and plants.
In Mesoamerica, Aztec philosophy was an intellectual tradition developed by individuals called Tlamatini ('those who know something')  and its ideas are preserved in various Aztec codices. The Aztec worldview posited the concept of an ultimate universal energy or force called Ometeotl which can be translated as "Dual Cosmic Energy" and sought a way to live in balance with a constantly changing, "slippery" world. The theory of Teotl can be seen as a form of Pantheism. Aztec philosophers developed theories of metaphysics, epistemology, values, and aesthetics. Aztec ethics was focused on seeking tlamatiliztli (knowledge, wisdom) which was based on moderation and balance in all actions as in the Nahua proverb "the middle good is necessary".
The Inca civilization also had an elite class of philosopher-scholars termed the Amawtakuna who were important in the Inca education system as teachers of religion, tradition, history and ethics. Key concepts of Andean thought are Yanantin and Masintin which involve a theory of "complementary opposites" that sees polarities (such as male/female, dark/light) as interdependent parts of a harmonious whole.
Philosophical questions can be grouped into categories. These groupings allow philosophers to focus on a set of similar topics and interact with other thinkers who are interested in the same questions. The groupings also make philosophy easier for students to approach. Students can learn the basic principles involved in one aspect of the field without being overwhelmed with the entire set of philosophical theories.
Various sources present different categorical schemes. The categories adopted in this article aim for breadth and simplicity.
These five major branches can be separated into sub-branches and each sub-branch contains many specific fields of study.
These divisions are neither exhaustive, nor mutually exclusive. (A philosopher might specialize in Kantian epistemology, or Platonic aesthetics, or modern political philosophy.) Furthermore, these philosophical inquiries sometimes overlap with each other and with other inquiries such as science, religion or mathematics.
Metaphysics is the study of the most general features of reality, such as existence, time, objects and their properties, wholes and their parts, events, processes and causation and the relationship between mind and body. Metaphysics includes cosmology, the study of the world in its entirety and ontology, the study of being.
A major point of debate is between realism, which holds that there are entities that exist independently of their mental perception and idealism, which holds that reality is mentally constructed or otherwise immaterial. Metaphysics deals with the topic of identity. Essence is the set of attributes that make an object what it fundamentally is and without which it loses its identity while accident is a property that the object has, without which the object can still retain its identity. Particulars are objects that are said to exist in space and time, as opposed to abstract objects, such as numbers, and universals, which are properties held by multiple particulars, such as redness or a gender. The type of existence, if any, of universals and abstract objects is an issue of debate.
Epistemology is the study of knowledge (Greek episteme). Epistemologists study the putative sources of knowledge, including intuition, a priori reason, memory, perceptual knowledge, self-knowledge and testimony. They also ask: What is truth? Is knowledge justified true belief? Are any beliefs justified? Putative knowledge includes propositional knowledge (knowledge that something is the case), know-how (knowledge of how to do something) and acquaintance (familiarity with someone or something). Epistemologists examine these and ask whether knowledge is really possible.
Skepticism is the position which doubts claims to knowledge. The regress argument, a fundamental problem in epistemology, occurs when, in order to completely prove any statement, its justification itself needs to be supported by another justification. This chain can go on forever, called infinitism, it can eventually rely on basic beliefs that are left unproven, called foundationalism, or it can go in a circle so that a statement is included in its own chain of justification, called coherentism.
Rationalism is the emphasis on reasoning as a source of knowledge. It is associated with a priori knowledge, which is independent of experience, such as math and logical deduction. Empiricism is the emphasis on observational evidence via sensory experience as the source of knowledge.
Among the numerous topics within metaphysics and epistemology, broadly construed are:
Value theory (or axiology) is the major branch of philosophy that addresses topics such as goodness, beauty and justice. Value theory includes ethics, aesthetics, political philosophy, feminist philosophy, philosophy of law and more.
Ethics, or "moral philosophy", studies and considers what is good and bad conduct, right and wrong values, and good and evil. Its primary investigations include how to live a good life and identifying standards of morality. It also includes meta-investigations about whether a best way to live or related standards exists. The main branches of ethics are normative ethics, meta-ethics and applied ethics.
A major area of debate involves consequentialism, in which actions are judged by the potential results of the act, such as to maximize happiness, called utilitarianism, and deontology, in which actions are judged by how they adhere to principles, irrespective of negative ends.
Aesthetics is the "critical reflection on art, culture and nature." It addresses the nature of art, beauty and taste, enjoyment, emotional values, perception and with the creation and appreciation of beauty. It is more precisely defined as the study of sensory or sensori-emotional values, sometimes called judgments of sentiment and taste. Its major divisions are art theory, literary theory, film theory and music theory. An example from art theory is to discern the set of principles underlying the work of a particular artist or artistic movement such as the Cubist aesthetic. The philosophy of film analyzes films and filmmakers for their philosophical content and explores film (images, cinema, etc.) as a medium for philosophical reflection and expression.
Political philosophy is the study of government and the relationship of individuals (or families and clans) to communities including the state. It includes questions about justice, law, property and the rights and obligations of the citizen. Politics and ethics are traditionally linked subjects, as both discuss the question of how people should live together.
Other branches of value theory:
Many academic disciplines generated philosophical inquiry. The relationship between "X" and the "philosophy of X" is debated. Richard Feynman argued that the philosophy of a topic is irrelevant to its primary study, saying that "philosophy of science is as useful to scientists as ornithology is to birds." Curtis White, by contrast, argued that philosophical tools are essential to humanities, sciences and social sciences.
Logic is the study of reasoning and argument. An argument is "a connected series of statements intended to establish a proposition." The connected series of statements are "premises" and the proposition is the conclusion. For example:
Deductive reasoning is when, given certain premises, conclusions are unavoidably implied. Rules of inference are used to infer conclusions such as, modus ponens, where given "A" and "If A then B", then "B" must be concluded.
Because sound reasoning is an essential element of all sciences, social sciences and humanities disciplines, logic became a formal science. Sub-fields include mathematical logic, philosophical logic, Modal logic, computational logic and non-classical logics. A major question in the philosophy of mathematics is whether mathematical entities are objective and discovered, called mathematical realism, or invented, called mathematical antirealism.
This branch explores the foundations, methods, history, implications and purpose of science. Many of its sub-divisions correspond to a specific branch of science. For example, philosophy of biology deals specifically with the metaphysical, epistemological and ethical issues in the biomedical and life sciences. The philosophy of mathematics studies the philosophical assumptions, foundations and implications of mathematics.
Some philosophers specialize in one or more historical periods. The history of philosophy (study of a specific period, individual or school) is related to but not the same as the philosophy of history (the theoretical aspect of history, which deals with questions such as the nature of historical evidence and the possibility of objectivity).
A variety of other academic and non-academic approaches have been explored.
The ideas conceived by a society have profound repercussions on what actions the society performs. Weaver argued that ideas have consequences. Philosophy yields applications such as those in ethics - applied ethics in particular - and political philosophy. The political and economic philosophies of Confucius, Sun Tzu, Chanakya, Ibn Khaldun, Ibn Rushd, Ibn Taymiyyah, Machiavelli, Leibniz, Hobbes, Locke, Rousseau, Adam Smith, John Stuart Mill, Marx, Tolstoy, Gandhi and Martin Luther King, Jr. have been used to shape and justify governments and their actions. Progressive education as championed by Dewey had a profound impact on 20th century US educational practices. Descendants of this movement include efforts in philosophy for children, which are part of philosophy education. Clausewitz's political philosophy of war has had a profound effect on statecraft, international politics and military strategy in the 20th century, especially around World War II. Logic is important in mathematics, linguistics, psychology, computer science and computer engineering.
Other important applications can be found in epistemology, which aid in understanding the requisites for knowledge, sound evidence and justified belief (important in law, economics, decision theory and a number of other disciplines). The philosophy of science discusses the underpinnings of the scientific method and has affected the nature of scientific investigation and argumentation. Philosophy thus has fundamental implications for science as a whole. For example, the strictly empirical approach of B. F. Skinner's behaviorism affected for decades the approach of the American psychological establishment. Deep ecology and animal rights examine the moral situation of humans as occupants of a world that has non-human occupants to consider also. Aesthetics can help to interpret discussions of music, literature, the plastic arts and the whole artistic dimension of life. In general, the various philosophies strive to provide practical activities with a deeper understanding of the theoretical or conceptual underpinnings of their fields.
Some of those who study philosophy become professional philosophers, typically by working as professors who teach, research and write in academic institutions. However, most students of academic philosophy later contribute to law, journalism, religion, sciences, politics, business, or various arts. For example, public figures who have degrees in philosophy include comedians Steve Martin and Ricky Gervais, filmmaker Terrence Malick, Pope John Paul II, Wikipedia co-founder Larry Sanger, Supreme Court Justice Stephen Bryer and vice presidential candidate Carly Fiorina.
Germany was the first country to professionalize philosophy. At the end of 1817, Hegel was the first philosopher to be appointed Professor by the State, namely by the Prussian Minister of Education, as an effect of Napoleonic reform in Prussia. In the United States, the professionalisation grew out of reforms to the American higher-education system largely based on the German model.
Within the last century, philosophy has increasingly become a professional discipline practiced within universities, like other academic disciplines. Accordingly, it has become less general and more specialized. In the view of one prominent recent historian: "Philosophy has become a highly organized discipline, done by specialists primarily for other specialists. The number of philosophers has exploded, the volume of publication has swelled, and the subfields of serious philosophical investigation have multiplied. Not only is the broad field of philosophy today far too vast to be embraced by one mind, something similar is true even of many highly specialized subfields." Some philosophers argue that this professionalization has negatively affected the discipline.
The end result of professionalization for philosophy has meant that work being done in the field is now almost exclusively done by university professors holding a doctorate in the field publishing in highly technical, peer-reviewed journals. While it remains common among the population at large for a person to have a set of religious, political or philosophical views that they consider their "philosophy", these views are rarely informed by or connected to the work being done in professional philosophy today. Furthermore, unlike many of the sciences for which there has come to be a healthy industry of books, magazines, and television shows meant to popularize science and communicate the technical results of a scientific field to the general populace, works by professional philosophers directed at an audience outside the profession remain rare. Philosopher Michael Sandel's book Justice: What's the Right Thing to Do? and Harry Frankfurt's On Bullshit are examples of works that hold the uncommon distinction of having been written by professional philosophers but directed at and ultimately popular among a broader audience of non-philosophers. Both works became 'New York Times best sellers.
Many inquiries outside of academia are philosophical in the broad sense. Novelists, playwrights, filmmakers, and musicians, as well as scientists and others engage in recognizably philosophical activity.
Ayn Rand is the foremost example of an intellectual working contemporaneously with contemporary philosophy but whose contributions were not made within the professional discipline of "philosophy": "For all her [Ayn Rand's] popularity, however, only a few professional philosophers have taken her work seriously. As a result, most of the serious philosophical work on Rand has appeared in non-academic, non-peer-reviewed journals, or in books, and the bibliography reflects this fact."
Also working from outside the profession were philosophers such as Gerd B. Achenbach (Die reine und die praktische Philosophie. Drei Vorträge zur philosophischen Praxis, 1983) and Michel Weber (see his Épreuve de la philosophie, 2008) who have proposed since the 1980s various forms of philosophical counseling claiming to bring Socratic dialogues back to life in a quasi-psychotherapeutic framework.
Pierre Hadot is famous for his analysis on the conception of philosophy during Greco-Roman antiquity. Hadot identified and analyzed the "spiritual exercises" used in ancient philosophy (influencing Michel Foucault's interest in such practices in the second and third volumes of his History of Sexuality). By "spiritual exercises" Hadot means "practices ... intended to effect a modification and a transformation in the subjects who practice them. The philosophy teacher's discourse could be presented in such a way that the disciple, as auditor, reader, or interlocutor, could make spiritual progress and transform himself within." Hadot shows that the key to understanding the original philosophical impulse is to be found in Socrates. What characterizes Socratic therapy above all is the importance given to living contact between human beings. Hadot's recurring theme is that philosophy in antiquity was characterized by a series of spiritual exercises intended to transform the perception, and therefore the being, of those who practice it; that philosophy is best pursued in real conversation and not through written texts and lectures; and that philosophy, as it is taught in universities today, is for the most part a distortion of its original, therapeutic impulse. He brings these concerns together in What Is Ancient Philosophy?, which has been critically reviewed.
Although men have generally dominated philosophical discourse, women have engaged in philosophy throughout history. Women philosophers have contributed since ancient times-notably Hipparchia of Maroneia (active ca. 325 BCE) and Arete of Cyrene (active 5th-4th century BCE). More were accepted during the ancient, medieval and modern eras, but no women philosophers became part the Western canon until the 20th and 21st century, when some sources indicate that Susanne Langer, Hannah Arendt and Simone de Beauvoir entered the canon.
In the early 1800s, some colleges and universities in the UK and US began admitting women, producing more female academics. Nevertheless, U.S. Department of Education reports from the 1990s indicate that few women ended up in philosophy, and that philosophy is one of the least gender-proportionate fields in the humanities. In 2014, Inside Higher Education described the philosophy "...discipline's own long history of misogyny and sexual harassment" of women students and professors.University of Sheffield philosophy professor Jennifer Saul stated in 2015 that women are "...leaving philosophy after being harassed, assaulted, or retaliated against." 
In the early 1990s, the Canadian Philosophical Association noted a gender imbalance and gender bias in the academic field of philosophy. In June 2013, a US sociology professor stated that "out of all recent citations in four prestigious philosophy journals, female authors comprise just 3.6 percent of the total." Susan Price argues that the philosophical "...canon remains dominated by white males - the discipline that...still hews to the myth that genius is tied to gender." According to Saul, "[p]hilosophy, the oldest of the humanities, is also the malest (and the whitest). While other areas of the humanities are at or near gender parity, philosophy is actually more overwhelmingly male than even mathematics."
In 2000, the Open Court Publishing Company began publishing a series of books on philosophy and popular culture. Each book consists of essays written by philosophers for general readers. The books "explore the meanings, concepts and puzzles within television shows, movies, music and other icons of popular culture" analyzing topics such as the TV shows Seinfeld and The Simpsons, The Matrix and Star Wars movies and related media and new technological developments such as the iPod and Facebook. Their most recent publication (as of 2016 ) is titled Louis C.K. and Philosophy; its subject is the comedian Louis C.K..
The Matrix makes numerous references to philosophy including Buddhism, Vedanta, Advaita Hinduism, Christianity, Messianism, Judaism, Gnosticism, existentialism and nihilism. The film's premise resembles Plato's Allegory of the cave, Descartes's evil demon, Kant's reflections on the Phenomenon versus the Ding an sich, Zhuangzi's "Zhuangzi dreamed he was a butterfly", Marxist social theory and the brain in a vat thought experiment. Many references to Baudrillard's Simulacra and Simulation appear in the film, although Baudrillard himself considered this a misrepresentation.
Philosophy is rationally critical thinking, of a more or less systematic kind about the general nature of the world (metaphysics or theory of existence), the justification of belief (epistemology or theory of knowledge), and the conduct of life (ethics or theory of value). Each of the three elements in this list has a non-philosophical counterpart, from which it is distinguished by its explicitly rational and critical way of proceeding and by its systematic nature. Everyone has some general conception of the nature of the world in which they live and of their place in it. Metaphysics replaces the unargued assumptions embodied in such a conception with a rational and organized body of beliefs about the world as a whole. Everyone has occasion to doubt and question beliefs, their own or those of others, with more or less success and without any theory of what they are doing. Epistemology seeks by argument to make explicit the rules of correct belief formation. Everyone governs their conduct by directing it to desired or valued ends. Ethics, or moral philosophy, in its most inclusive sense, seeks to articulate, in rationally systematic form, the rules or principles involved.in Honderich 1995.
The English word "philosophy" is first attested to c. 1300, meaning "knowledge, body of knowledge."
Ancient Greek philosophy was divided into three branches of knowledge: natural science, ethics, and logic.
E*pis`te*mol"o*gy (?), n. [Gr. knowledge + -logy.] The theory or science of the method or grounds of knowledge.