Philosophy is a field of study in which people question and create theories about the nature of reality and human presence in the universe. It includes diverse subfields such as aesthetics, epistemology, ontology, ethics, logic, metaphysics, and law. Philosophers concern themselves with such fundamental and mysterious topics as whether or not God(s) exist, what is the nature of being and the universe, what is truth, what is consciousness, and what makes actions right or wrong. The fundamental method of western philosophy is the use of reasoning to evaluate arguments. However, the methodology of philosophy is itself debated, and varies according to the philosophical and cultural traditions of people all over the world.
Many societies have considered philosophical questions and built philosophical traditions based upon each other's works. Eastern and Middle Eastern philosophical traditions have influenced Western philosophers. Russian, Jewish, Islamic and recently Latin American philosophical traditions have contributed to, or been influenced by, Western philosophy, yet each has retained a distinctive identity.
The differences between traditions are often based on their favored historical philosophers, and varying stress on ideas, procedural styles, or written language. The subject matter and dialogues of each can be studied using methods derived from the others, and there are significant commonalities and exchanges between them.
"Eastern philosophy" refers to the broad traditions that originated or were popular in India, Persia, China, Japan, and to an extent, the Middle East (which overlaps with Western philosophy due to being the origin of the Abrahamic religions).
- Further information: Hindu philosophy, Buddhist philosophy, and Jainism
Hindu philosophy constitutes an integral part of the culture of Southern Asia, and is the first of the Dharmic philosophies which were influential throughout the Far East. The great diversity in thought and practice of Hinduism is nurtured by its liberal universalism.
The origins of Hindu philosophy are to be traced in Vedic deliberations about the universe and Rta ("universal order"), the first of which was the Rig-Veda, composed in the 2nd millenium BC. Other major texts with philosophical implications include the Upanishads, the Bhagavad Gita, and the Brahma Sutra, from circa 1000 BCE to 500 BCE. The Indian epics Mahabharata and Ramayana also cover Indian philosophy in much depth. At about the same time, the shramana schools, including Jainism and Buddhism, also developed. It is notable that the Vedanta schools of Hindu philosophy are still living traditions today. Hinduism has no known founder or single, authoritative text .
Hindu philosophy is traditionally seen through the prism of six different systems (called darshanas in Sanskrit). The six major Astika schools of thought are the Samkhya (enumeration), Yoga (union), Nyaya (logic), Vaisheshika (atomism), Mimamsa (investigation), and Vedanta (culmination of the Vedas) schools. The Vedanta school is further divided into six sub-schools: Advaita (monism/nondualism), VisishtAdvaita (monism of the qualified whole), Dvaita (dualism), Dvaitadvaita (dualism-nondualism), Suddhadvaita, and Acintya Bheda Abheda schools.
Buddhist philosophy is a system of beliefs based on the teachings of Siddhartha Gautama, an Indian prince later known as the Buddha, derived from the Sanskrit 'bud', 'to awaken'. Buddhism is a non-theistic religion, one whose tenets are not especially concerned with the existence or nonexistence of a God or gods. The Buddha himself expressly disavowed any special divine status or inspiration, and said that anyone, anywhere could achieve all the insight that he had. The question of God is largely irrelevant in Buddhism, though some sects (notably Tibetan Buddhism) do venerate a number of gods drawn in from local indigenous belief systems.
From its inception, Buddhism has had a strong philosophical component. Buddhism is founded on the rejection of certain orthodox Hindu philosophical concepts, in which the Buddha had been instructed by various teachers. Buddhism rejects atheism, theism, monism, and dualism alike. The Buddha criticized all concepts of metaphysical being and non-being, and this critique is inextricable from the founding of Buddhism.
Most Buddhist sects believe in karma, a cause-and-effect relationship between all that has been done and all that will be done. Events that occur are held to be the direct result of previous events. One effect of karma is rebirth. At death, the karma from a given life determines the nature of the next life's existence. The ultimate goal of a Buddhist practitioner is to eliminate karma (both good and bad), end the cycle of rebirth and suffering, and attain Nirvana, usually translated as awakening or enlightenment.
Jaina philosophy, founded by Mahavira (599-527 BCE), is based upon eternal, universal truths, according to its followers. Over a period of time, these truths may lapse among humanity and then reappear through the teachings of enlightened humans, those who have reached enlightenment or total knowledge (Keval Gnan).
Anekantavada is a basic principle of Jainism positing that reality is perceived differently from different points of view, and that no single point of view is completely true. Jain doctrine states that only Kevalis, those who have infinite knowledge, can know the true answer, and that all others would only know a part of the answer. Anekantavada is related to the Western philosophical doctrine of Subjectivism.
- See also: Zoroastrianism and Islamic philosophy
The teachings of Zarathushtra (Zoroaster) appeared in Persia at some point during the period between 1000-588 BCE.  His wisdom became the basis of the religion Zoroastrianism, and generally influenced the development of the Iranian branch of Indo-Iranian philosophy. Zarathushtra was the first who treated the problem of evil in philosophical terms.  He is also believed to be one of the oldest monotheists in the history of religion. He espoused an ethical philosophy based on the primacy of good thoughts (humata), good words (hukhata), and good deeds (hvarshatra).
Zarathushtra was known as a sage, magician and miracle-worker in post-Classical Western culture, though almost nothing was known of his ideas until the late eighteenth century. By this time his name was associated with lost ancient wisdom and was appropriated by Freemasons and other groups who claimed access to such knowledge. He appears in Mozart's opera "Die Zauberflöte" under the variant name "Sarastro", who represents moral order in opposition to the "Queen of the Night". Enlightenment writers such as Voltaire promoted research into Zoroastrianism in the belief that it was a form of rational Deism, preferable to Christianity.
In 2005, the Oxford Dictionary of Philosophy ranked Zarathushtra number two in the chronology of philosophical events.  Zarathushtra's impact lingers today due in part to the system of rational ethics he founded called Mazda-Yasna. The word Mazda-Yasna is avestan and is translated as "Worship of Wisdom" in English. The Greeks later used a similar word to the Iranian one – the word "philosophy" in Greek literally means "love of wisdom".
Throughout Iranian history, due to Greek and Arabic influence, a wide spectrum of schools of thoughts showed a variety of views on philosophical questions extending from Old Iranian and Zoroastrian traditions, to schools appearing in the late pre-Islamic era, to various Islamic schools. Iranian philosophy after the Arab invasion of Persia is characterized by different interactions with the Old Iranian philosophy with Greek and Islamic philosophy. The Illumination School and the Transcendent Philosophy are regarded as two of the main philosophical traditions of that era in Persia.
Manicheism, founded by Mani, was influential from North Africa in the West, to China in the East. Its influence subtly continues in Western Christian thought via Saint Augustine of Hippo, who converted to Christianity from Manichaeism, which he passionately denounced in his writings, and whose writings continue to be influential among Catholic, Protestant, and Orthodox theologians. An important principle of Manicheism was its dualistic cosmology/theology, which it shared with Mazdakism, a philosophy founded by Mazdak. Under this dualism, there were two original principles of the universe: Light, the good one; and Darkness, the evil one. These two had been mixed by a cosmic accident, and man's role in this life was through good conduct to release the parts of himself that belonged to Light. Mani saw the mixture of good and bad as a cosmic tragedy, while Mazdak viewed this in a more neutral, even optimistic way.
In the Islamic era, various Persian philosophers contributed to Islamic philosophy. Al-Farabi discussed the philosophy of Plato and Aristotle elaborately. He hypothesized an "ideal state" in his work Al-Madina al-fadila. His ideas were not extreme, rather he often tried to unify many contradictory ideas. He accepted the supremacy of a creator, while admitting the absoluteness of creation. His idealized state-leader in Al-Madina al-fadila is an autocrat. This philosophy had an impact on centralizing then divided Feudal societies. He explicitly claimed that attaining ideal state is impossible, but the struggle should be encouraged.
Avicenna (Ibn Sina) wrote extensively on the subjects of philosophy, logic, ethics, metaphysics and other disciplines. Most of his works were written in Arabic, which was the de facto scientific language of that time, while some were written in Persian. Ibn Sina's commentaries on Aristotle often corrected the philosopher, encouraging a lively debate in the spirit of ijtihad. His Logic, Metaphysics, Physics, and De Caelo, are treatises giving a synoptic view of Aristotelian doctrine. The Logic and Metaphysics have been printed more than once in Europe. Some of his shorter essays on logic take a poetical form, which was also later published in Europe. He wrote two encyclopaedic treatises dealing with philosophy, known as the Al-Shifa (Sanatio in Latin) and An-najat (Liberatio in Latin). He also wrote a Philosophia Orientalis, mentioned by Roger Bacon, which according to Averroes was pantheistic in tone. Arabic philosophy flourished after Avicenna's death, emerging from Avicenna's inflammatory pronouncements on all matters within the world, whether physical or metaphysical, such as the works of the post-Avicennian Baghdadi Peripatetics and anti-Peripatetics.
Philosophy has had a tremendous effect on Chinese civilization, and East Asia as a whole. Many of the great philosophical schools were formulated during the Spring and Autumn Period and Warring States Period, and came to be known as the Hundred Schools of Thought. The four most influential of these were Confucianism, Taoism, Mohism, and Legalism. Later on, during the Tang Dynasty, Buddhism from India also became a prominent philosophical and religious discipline. (It should be noted that Eastern thought, unlike Western philosophy, did not express a clear distinction between philosophy and religion.) Like Western philosophy, Chinese philosophy covers a broad and complex range of thought, possessing a multitude of schools that address every branch and subject area of philosophy.
In China, the Tao Te Ching (Dào dé jīng, in pinyin romanisation) of Lao Tzu (Lǎo zǐ)  and the Analects of Confucius (Kǒng fū zǐ; sometimes called Master Kong)  both appeared around 600 BCE, about the time that the Greek pre-Socratics were writing.
Of all the Chinese philosophies, however, it is quite safe to say Confucianism has had the greatest impact throughout East Asia. Confucianism represents the collected teachings of the Chinese sage Confucius, who lived from 551 to 479 BCE. His philosophy focused in the fields of ethics and politics, emphasizing personal and governmental morality, correctness of social relationships, justice, traditionalism, and sincerity. Confucianism, along with Legalism, is responsible for creating the world’s first meritocracy, which holds that one's status should be determined by ability instead of ancestry, wealth, or friendships.  It is arguable that Confucianism is most responsible for shaping the Chinese culture and state of China.
Throughout history, Chinese philosophy has been molded to fit the prevailing school of thought in China. The Chinese schools of philosophy, except during the Qin Dynasty, have been relatively tolerant of one another. Instead of competing, they generally have cooperated and shared ideas, which they would usually incorporate with their own. For example, Neo-Confucianism was a revived version of old Confucian principles that appeared around the Song Dynasty, with Buddhist, Taoist, and Legalist features.
During the Industrial and Modern Ages, Chinese philosophy had also began to integrate concepts of Western philosophy, as steps toward modernization. By the time of the Xinhai Revolution in 1911, there were many calls, such as the May Fourth Movement, to completely abolish the old imperial institutions and practices of China. There have been attempts to incorporate democracy, republicanism, and industrialism into Chinese philosophy, notably by Sun Yat-Sen (Sūn yì xiān, in one Mandarin form of the name) at the beginning of the 20th century. Mao Tse-Tung (Máo zé dōng) added Marxism, Stalinism, and other communist thought. The current government of the People's Republic of China is trying to encourage a form of market socialism. Although, officially, the Communist Party of China does not recognize, and even forbid, any of the philosophical practices of Imperial China, the influences of past are still deeply ingrained in the Chinese culture. As in Japan, philosophy in China has become a melting pot of ideas. It accepts new concepts, while attempting also to accord old beliefs their due.
Chinese philosophy has spread around the world in forms such as the so-called New Confucianism and New Age ideas (see for example Chinese traditional medicine). Many in the academic community of the West, however, remain skeptical, and only a few assimilate Chinese philosophy into their own research, whether scientific or philosophical.
See also: Yin-Yang, Qi, Tao, Li, I Ching
Related Topics: Korean philosophy, Bushido, Zen, The Art of War
Other philosophical traditions, such as African philosophy, are rarely considered by foreign academia. Since emphasis is mainly placed on western philosophy as a reference point, the study, preservation and dissemination of valuable, but lesser known, non-Western philosophical works face many obstacles.
Metaphysics and epistemology
Rationalism and empiricism
René Descartes, who is often called the father of modern philosophy, proposed that philosophy should begin with a radical skepticism about the possibility of obtaining reliable knowledge. In 1641, in Meditations on First Philosophy, he used this method of doubt in an attempt to establish what knowledge is most certain. He chose as the foundation of his philosophy the famous statement Cogito ergo sum ("I think, therefore I am"). He then attempted to rebuild a system of knowledge based on this single supposedly indubitable fact.  His approach became known as a species of rationalism; it attracted such philosophers as Baruch Spinoza, Gottfried Leibniz, and Christian Wolff.
In response to the popularity of rationalism, John Locke wrote An Essay Concerning Human Understanding in 1689, developing a form of naturalism and empiricism on roughly scientific principles. Hume's work A Treatise of Human Nature (1739-40) combined empiricism with a spirit of skepticism. Other philosophers who made major contributions to empiricism include Thomas Hobbes and George Berkeley (Bishop Berkeley).
During this era, religious ideas played a mixed role in the struggles that preoccupied secular philosophy. Bishop Berkeley's famous idealist refutation of Isaac Newton is a case of an Enlightenment philosopher who drew substantially from religious ideas. Other influential religious thinkers of the time include Blaise Pascal, Joseph Butler, and Jonathan Edwards. Other major writers, such as Jean-Jacques Rousseau and Edmund Burke, took a slightly different path. The restricted interests of many of the philosophers of the time foreshadow the separation and specialization of different areas of philosophy that would occur in the twentieth century.
Kantian philosophy and the rise of idealism
Immanuel Kant wrote his Critique of Pure Reason (1781/1787) in an attempt to reconcile the conflicting approaches of rationalism and empiricism and establish a new groundwork for studying metaphysics. Kant's intention with this work was to look at what we know and then consider what must be true about the way we know it. One major theme was that there are fundamental features of reality that escape our direct knowledge because of the natural limits of the human faculties. Kant's method was modeled on Euclid, though he eventually acknowledged that pure reason was insufficient to discover all truth. Kant's work was continued in the work of Johann Gottlieb Fichte, Friedrich Schelling, and Arthur Schopenhauer.
Kant's philosophy, known as transcendental idealism, would later be made more abstract and more general, in the movement known as German idealism, a type of absolute idealism. German idealism rose to popularity with G. W. F. Hegel's publication in 1807 of Phenomenology of Spirit. In that work, Hegel asserts that the aim of philosophy is to spot the contradictions apparent in human experience (which arise, for instance, out of the recognition of the self as both an active, subjective witness and a passive object in the world) and to get rid of these contradictions by making them compatible. Hegel wrote that every thesis creates its own antithesis, and that out of the two arises a synthesis. This process is known as the "Hegelian dialectic". Philosophers in the Hegelian tradition include Ludwig Andreas Feuerbach, Karl Marx, Friedrich Engels, and sometimes the British idealists.
The late nineteenth century brought about the rise of a new philosophy in the Americas. Charles Peirce and William James are considered to be the co-founders of loosely allied schools of pragmatism, which introduced what would later be called instrumentalism, the idea that what is important for a good theory is how useful it is, not how well it represents reality. Thinkers in this tradition included John Dewey, George Santayana, and C. I. Lewis. Though not widely recognized under the term "pragmatist", philosophers like Henri Bergson and G. E. Moore shared many of the same foundational assumptions with the pragmatists. Pragmatism has recently been taken in new directions by Richard Rorty and Hilary Putnam.
The prominence of logic
Gottlob Frege and the early Edmund Husserl were interested in the philosophy of mathematics. Husserl's work Philosophy of Arithmatic, inspired by the teachings of Weierstrass, hoped to show that the concept of the cardinal number was the foundation of arithmetic.  The prospects for this project dwindled as Husserl entertained more and more doubts in the final chapters of that same work, culminating in the abandonment of the project by the 1890s. Husserl's philosophical change may have been helped along to a modest extent by Frege's critiques of psychologism. Frege's own work, the Begriffsschrift, developed the concepts of modern predicate logic by making use of the notions of the object and the function, and which would provide one alternative to psychologistic accounts of number.
Frege, and to a lesser extent, Husserl, influenced the logicians Bertrand Russell and Alfred North Whitehead. After the latters published Principia Mathematica (1910-1913), many philosophers took a renewed interest in the problems of mathematical logic. With this increased interest in mathematical logic came the rise in popularity for the view known as logical positivism and related theories, all of which shared a commitment to the reliability of empirical tests. Philosophers such as Rudolf Carnap and Hans Reichenbach, along with the members of the Vienna Circle in general, considered only verifiable claims to be genuine philosophy; anything that could not be deduced from testable claims was considered mere superstition or dogma. Karl Popper's insistence upon the role of falsification in the philosophy of science was a reaction to the logical positivists. 
Phenomenology and hermeneutics
At the same time that the analytic movement was coming to prominence in America and Britain, a separate movement occurred in continental Europe. Under the influence of Franz Brentano, the later Edmund Husserl developed a new method to study human problems in his Logical Investigations (1901) and Ideas (1913). The method, known as phenomenology, was used to examine the details of human experience and consciousness in order to observe the most basic facts of human existence; the examination included not just observations of the way the world appears but observations of one's own thoughts, and when and how they occur. This method was developed further in the work of Martin Heidegger and Maurice Merleau-Ponty.
Heidegger expanded the study of phenomenology to elaborate a philosophical hermeneutics. Hermeneutics is a method of interpreting texts by drawing out the meaning of the text in the context it was written in. Heidegger stressed two new elements of philosophical hermeneutics: that the reader brings out the meaning of the text in the present, and that the tools of hermeneutics can be used to interpret more than just texts (e.g. "social text").  Elaborations of philosophical hermeneutics later came from Hans-Georg Gadamer and Paul Ricoeur.
In the mid-twentieth century, existentialism developed in Europe, particularly in France and Germany. The most prominent exponent of existentialism is Jean-Paul Sartre, although existentialist thought received major impetus from the nineteenth century philosophers Søren Kierkegaard and Friedrich Nietzsche, both of whom pre-date existentialism and whose contributions extend beyond existentialist thought.
Kierkegaard, a Danish philosopher generally considered the "Father of Existentialism", argued that "truth is subjectivity", meaning that what is most important to an existing being are questions dealing with an individual's inner relationship to existence. Objective truths (e.g. mathematical truths) are important, but detached or observational modes of thought can never truly comprehend human experience. Kierkegaard postulated complex ethico-religious philosophical premises, based in part on the three stages on life's way: the aesthetic, the ethical, and the religious.  Nietzsche postulated complex aesthetico-philosophical premises, based in part upon the concept of the will to power. Existentialists sometimes view Nietzsche's thought as characteristic of existentialism, due to the manner in which it places high value in individualism and self-creation, or self-defining.
Drawing on these ideas, existentialism rejects the notion of a human essence, instead trying to draw out the ability of each person to live authentically, which is to say that each person is able to define and determine his or her own life. Sartre's expression of existentialism in Being and Nothingness (1943). Other influential existentialists include Albert Camus, Simone de Beauvoir, Maurice Merleau-Ponty and Karl Jaspers. Fyodor Dostoevsky, Franz Kafka, and other literary figures, although not usually considered philosophers, have also contributed greatly to this thought.
The Analytic tradition
The tenor of mid-twentieth century philosophy in Anglo- nations was not as united behind a major philosophical idea as it had been in the past. Still, a general philosophical method can be abstracted from the philosophy that was going on at the time.
Analytic philosophy developed as a reaction against obscure, vague, and neologistic pronouncements by Hegel and his followers. In 1921, Ludwig Wittgenstein published his Tractatus Logico-Philosophicus, which gave a rigidly logical account of linguistic and philosophical issues. At the time, he understood most of the problems of philosophy as mere puzzles of language, which could be solved by clear thought. Years later he would reverse a number of his positions set out in the Tractatus, as revealed by the content of his second major work, Philosophical Investigations (1953). Investigations encouraged the development of "ordinary language philosophy", which was developed by Gilbert Ryle, J. L. Austin, and a few others. The "ordinary language philosophy" thinkers shared a common outlook with many older philosophers (Jeremy Bentham, Ralph Waldo Emerson, and John Stuart Mill), and it was the philosophical inquiry that characterized English-language philosophy for the second half of the twentieth century. Still, the clarity of meaning was understood to be of ultimate significance.
The implied outlook for "ordinary language philosophy" is that problems in one area of philosophy can be solved independently of problems in other areas of philosophy. Philosophy is thus not a unified whole but a set of unrelated problems. Great thinkers whose work indicates an acceptance of this general outlook include Albert Einstein, Sigmund Freud, P. F. Strawson, Donald Davidson, Hilary Putnam, Tadeusz Kotarbiński, John Rawls, Noam Chomsky, and the continental thinker Mikhail Bakhtin.
Since then, a plurality of new movements has passed through English-language philosophy. Drawing on the metaphilosophical observation made by Wittgenstein in his second major work, Philosophical Investigations, in which he notes that a good approach to philosophy must itself be based on a careful examination of the meaning of language, a new group of philosophers have adopted a methodological skepticism. This is seen most prominently in the work of W. V. O. Quine and Wilfrid Sellars (but with ideas going back to Auguste Comte and Whitehead). The group's concerns converge on the ideas of naturalism, holism (in opposition to most of what is considered analytic philosophy), instrumentalism, and the denial of Platonic universals. A number of other perspectives have branched out from Wittgenstein's legacy. In any case, most analytic philosophers currently working do not consider themselves affiliated with any particular school of thought, such as logical positivism or ordinary-language philosophy, and approach philosophy and its problems in a more piecemeal manner than earlier philosophers did.
Ethics and political philosophy
Human nature and political legitimacy
From ancient times, and well beyond them, the roots of justification for political authority were inescapably tied to outlooks on human nature. In The Republic, Plato declared that the ideal society would be run by an aristocracy of philosopher-kings, since those best at philosophy are best able to realize the good. Even Plato, however, required philosophers to make their way in the world for many years before beginning their rule at the age of fifty. For Aristotle, humans are political animals (i.e. social animals), and governments are set up in order to pursue good for the community. Aristotle reasoned that, since the state (polis) was the highest form of community, it has the purpose of pursuing the highest good. Aristotle understood political power to be the result of natural inequalities in skill and virtue. Because of these differences, he favored an aristocracy of the able and virtuous. For Aristotle, the person cannot be complete unless he or she lives in a community. His two books, The Nicomachean Ethics and The Politics, are meant to be read in that order. The first book addresses virtues/excellences in the person as a citizen; the second addresses the proper form of government to ensure virtuous (and thus complete) citizens. Both books deal with the essential role of justice as a necessary virtue in civic life.
Two millennia later, Niccolò Machiavelli, rejected Aristotle's (and Thomas Aquinas') view as unrealistic. The ideal sovereign is not the embodiment of the moral virtues; rather the sovereign does what's successful and necessary rather than what's morally praiseworthy. Thomas Hobbes also contested many elements of Aristotle's views. For Hobbes, human nature is essentially anti-social: people are essentially egoistic, and this egoism makes life difficult in the natural state of things. Moreover, Hobbes argued, though people may have natural inequalities, these are trivial, since no particular talents or virtues that a person may have will make them safe from harm inflicted by others. For these reasons, Hobbes concluded that the state arises from common agreement to raise the community out of the state of nature. This can only be done by the establishment of a sovereign, which (or who) is vested with complete control over the community, and is able to inspire awe and terror in its subjects.
Many in the Enlightenment were unsatisfied with existing doctrines in political philosophy, which seemed to marginalize or neglect the possibility of a democratic state. One attempt to overturn these doctrines was that of Jean-Jacques Rousseau, who responded to Hobbes by claiming that a human is by nature a kind of "noble savage", and that society and social contracts corrupt this nature. In his Second Treatise on Government John Locke agreed with Hobbes that the nation-state was an efficient tool for raising humanity out of a deplorable state, but argued that the sovereign may become an abominable institution compared to the relatively benign unmodulated state of nature. 
Following the doctrine of the fact-value distinction, due in part to the influence of David Hume, appeals to human nature for political justification were weakened. Nevertheless, many political philosophers, especially moral realists, still make use of some essential human nature as a basis for their arguments.
Consequentialism, deontology, and the aretaic turn
One debate that has dominated the attention of ethicists in the history of the modern era has been between consequentialism (the idea that the consequences of a particular action form the basis for any valid moral judgement about that action) and deontology (that decisions should be made solely or primarily by considering one's duties and the rights of others).
Jeremy Bentham and John Stuart Mill are famous for propagating utilitarianism, which is the idea that the fundamental moral rule is to strive toward the "greatest happiness for the greatest number". However, in promoting this idea they also necessarily promoted the broader doctrine of consequentialism: that is to say, the idea that the morally right thing to do in any situation is determined by the consequences of the actions under consideration.
In contrast to consequentialism, Immanuel Kant argued that moral principles were simply products of reason. Kant believed that the incorporation of consequences into moral deliberation was a deep mistake, since it would deny the necessity of practical maxims to the working of the will. According to Kant, reason requires that we conform our actions to the categorical imperative, which is an absolute duty. An important 20th-century deontologist, W.D. Ross, argued for weaker forms of duties called prima facie duties.
More recent works have emphasized the role of character in ethics, a movement known as the aretaic turn. One strain of this movement followed the work of Bernard Williams. Williams noted that rigid forms of both consequentialism and deontology demanded that people behave impartially. This, Williams argued, requires that people abandon their personal projects, and hence their personal integrity, in order to be considered moral.
G.E.M. Anscombe, in an influential paper, "Modern Moral Philosophy" (1958), revived virtue ethics, inspired by Aristotle's ethics, as an alternative to what was seen as the entrenched positions of Kantianism and consequentialism. Virtue ethics has since gained some adherence and has been defended by such philosophers as Philippa Foot, Alasdair MacIntyre and Rosalind Hursthouse.
Though often seen as a wholly abstract field, philosophy is not without practical applications. The most obvious applications are those in ethics – applied ethics in particular – and in political philosophy. The political philosophies of Confucius, Kautilya, Sun Zi, Immanuel Kant, John Locke, Thomas Hobbes, Niccolò Machiavelli, Jean-Jacques Rousseau, Karl Marx, John Stuart Mill, Mahatma Gandhi, Robert Nozick, and John Rawls have shaped and been used to justify the existence of governments and their actions.
In the field of the philosophy of education, progressive education as championed by John Dewey has had a profound impact on educational practices in the United States in the twentieth century. Descendents of this movement include the current Philosophy for Children efforts. Carl von Clausewitz's political philosophy of war has had a profound effect on statecraft, international politics and military strategy in the 20th century, especially in the years around World War II.
Other important applications can be found in epistemology, which aid in understanding the notions of what knowledge, evidence, and justified belief are. The philosophy of science discusses the underpinnings of the scientific method. Deep ecology and animal rights examine the place of humans in the moral configuration of reality as a whole. Aesthetics can help to interpret discussions of art. The work of Fernando Flores and Terry Winograd shows how the philosophy of J.L. Austin can be used to guide the design of an electronic mail program.
In general, the various "philosophies of..." such as the philosophy of law, can provide workers in their respective fields with a deeper understanding of the theoretical or conceptual underpinnings of their fields.
Often philosophy is seen as an investigation into an area not understood well enough to be its own branch of knowledge. What were once philosophical pursuits have evolved into the modern day fields of psychology, sociology, linguistics, and economics (among others).
Confines of Philosophy
What should, and what should not, be counted as philosophy – and who counts as a philosopher – has been heavily debated. Historically, philosophy has been associated with certain subjects. Still, the search continues for a pattern which unites the disparate philosophical activities and interests of those who study those subjects. A handful of candidate explanations can nevertheless be assembled. 
Metaphilosophical relativists may claim that any statement can be counted as a philosophical statement, as there is no objective way to disqualify it of being so. Also, the very open-minded nature of philosophy makes many people skeptical when it comes to limiting the concept of philosophy to something tangible and not something open-ended. However, several philosophers or philosophical directions have had ideas about what philosophy is and what it should not be.
Plato, or the protagonist in his dialogues, Socrates, held up a number of virtues for philosophers. Amongst other things, he rejected that rhetorics had a place in philosophy (most famously in Gorgias).
The logical positivists denied the soundness of metaphysics and traditional philosophy, and affirmed that statements about metaphysics, religion and ethics are devoid of cognitive meaning and thus nothing but expression of feelings or desires.
What constitutes sound philosophical work is sometimes summed up by the term Philosophical method. Also, it is often agreed upon that arguments should try to follow the rules of logic and avoid fallacies. It has also been argued that the scientific method should be followed as closely as the subject-matter allows. If a branch of philosophy at some point fully can start following the norms of the scientific method, it is no longer termed philosophy, but science. 
Disparaging terms have been created in order to provide examples of non-philosophers and non-philosophy. "Pseudophilosophy" is used to describe those activities which are not associated with a sensible kind of inquiry, and "philosophaster" is a term used to describe those who engage in pseudophilosophy.
Philosophers on Philosophy
What is philosophy? Some would respond by listing its major subfields such as logic, ethics, and epistemology; on the other hand, it has also been said that "philosophy is the study of its own history" (viz., its own literature). However, some noted philosophers have attempted to address these issues central to philosophy's subject matter and how it is treated:
... [philosophy] is the acquisition of knowledge.
—Plato, Euthydemus, 288d.
... [that] philosophy only is the true one which reproduces most faithfully the statements of nature, and is written down, as it were, from nature's dictation, so that it is nothing but a copy and a reflection of nature, and adds nothing of its own, but is merely a repetition and echo.
—Francis Bacon, The Enlargement of Science, 1. 2, ch. 3
To repeat abstractly, universally, and distinctly in concepts the whole inner nature of the world, and thus to deposit it as a reflected image in permanent concepts always ready for the faculty of reason, this and nothing else is philosophy.
—Arthur Schopenhauer, The World as Will and Representation, Vol. I, §68
Philosophy is the science by which the natural light of reason studies the first causes or highest principles of all things – is, in other words, the science of things in their first causes, in so far as these belong to the natural order.
—Jacques Maritain, An Introduction to Philosophy, 69
The object of philosophy is the logical clarification of thoughts. Philosophy is not a theory but an activity. A philosophical work consists essentially of elucidations. The result of philosophy is not a number of ‘philosophical propositions’, but to make propositions clear. Philosophy should make clear and delimit sharply the thoughts which otherwise are, as it were, opaque and blurred.
—Ludwig Wittgenstein, Tractatus Logico-Philosophicus, 4.112
... [philosophers] are not honest enough in their work, although they make a lot of virtuous noise when the problem of truthfulness is touched even remotely. They all pose as if they had discovered and reached their real opinions through the self-development of a cold, pure, divinely unconcerned dialectic...; while at bottom it is an assumption, a hunch, indeed a kind of “inspiration”—most often a desire of the heart that has been filtered and made abstract—that they defend with reasons they have sought after the fact.
—Friedrich Nietzsche, Beyond Good and Evil, Part One: On the Prejudices of Philosophers, §5
To grasp the limits of reason – only this is truly philosophy.
—Friedrich Nietzsche, The Antichrist (book), §55
Philosophy, being nothing but the study of wisdom and truth...
—George Berkeley, A Treatise Concerning the Principles of Human Knowledge, Introduction, §1
...for wonder is the feeling of a philosopher, and philosophy begins in wonder.
—Plato, Theaetetus, 155
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- Syllabus for General Philosophy I, an introductory philosophy course currently offered by the Academe of Philosophical Studies at the University of No Where. Check back often for lectures, essays, articles, and other updates.
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- The Branches of Philosophy
- A Glossary of Terms
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- Classics of Philosophy: The 20th Century (Vol. 3) by Louis P. Pojman
- The English Philosophers from Bacon to Mill by Edwin Arthur Burtt
- European Philosophers from Descartes to Nietzsche by Monroe Beardsley
- Contemporary Analytic Philosophy: Core Readings by James Baillie
- Existentialism: Basic Writings (Second Edition) by Charles Guignon, Derk Pereboom
- The Phenomenology Reader by Dermot Moran, Timothy Mooney
- Medieval Islamic Philosophical Writings edited by Muhammad Ali Khalidi
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- A Source Book in Chinese Philosophy by Wing-tsit Chan
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- The Oxford Companion to Philosophy edited by Ted Honderich
- The Cambridge Dictionary of Philosophy by Robert Audi
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- The Concise Routledge Encyclopedia of Philosophy edited by Edward Craig (an abridgement)
- Encyclopedia of Philosophy (8 vols.) edited by Paul Edwards; in 1996, a ninth supplemental volume appeared which updated the classic 1967 encyclopedia.
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- Encyclopaedia of Indian Philosophies (8 vols.), edited by Karl H. Potter et al (first 6 volumes out of print)
- Indian Philosophy (2 vols.) by Sarvepalli Radhakrishnan
- A History of Indian Philosophy (5 vols.) by Surendranath Dasgupta
- History of Chinese Philosophy (2 vols.) by Fung Yu-lan, Derk Bodde
- Encyclopedia of Chinese Philosophy edited by Antonio S. Cua
- Encyclopedia of Eastern Philosophy and Religion by Ingrid Fischer-Schreiber, Franz-Karl Ehrhard, Kurt Friedrichs
- Companion Encyclopedia of Asian Philosophy by Brian Carr, Indira Mahalingam
- A Concise Dictionary of Indian Philosophy: Sanskrit Terms Defined in English by John A. Grimes
- History of Islamic Philosophy edited by Seyyed Hossein Nasr, Oliver Leaman
- History of Jewish Philosophy edited by Daniel H. Frank, Oliver Leaman
- A History of Russian Philosophy: From the Tenth to the Twentieth Centuries by Valerii Aleksandrovich Kuvakin
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- Popkin, R. H. (1999). The Columbia History of Western Philosophy. New York, Columbia University Press.
- An historical time line.
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