Some Definitions

• the discipline concerned with questions of how one should live (ethics); what sorts of things exist and what are their essential natures (metaphysics); what counts as genuine knowledge (epistemology); and what are the correct principles of reasoning (logic) (Wikipedia)

• investigation of the nature, causes, or principles of reality, knowledge, or values, based on logical reasoning rather than empirical methods (American Heritage Dictionary)

• the study of the ultimate nature of existence, reality, knowledge and goodness, as discoverable by human reasoning (Penguin English Dictionary)

• the rational investigation of questions about existence and knowledge and ethics (WordNet)

• the search for knowledge and truth, especially about the nature of man and his behaviour and beliefs (Kernerman English Multilingual Dictionary)

• the rational and critical inquiry into basic principles (Microsoft Encyclopedia)

• the study of the most general and abstract features of the world and categories with which we think: mind, matter, reason, proof, truth, etc. (Oxford Dictionary of Philosophy)

• careful thought about the fundamental nature of the world, the grounds for human knowledge, and the evaluation of human conduct (The Philosophy Pages)

The ancient Greeks meant by the term "philosophy" the pursuit of knowledge for its own sake, and understood it as the discipline that encompasses all areas of speculative thought, including the arts, sciences and religion.

Philosophical questions (unlike those of the sciences) are usually foundational and abstract in nature. Philosophy is done primarily through reflection and does not tend to rely on experiment, although the methods used to study it may be analogous to those used in the study of the natural sciences.

In common usage, it sometimes carries the sense of unproductive musings, but over the centuries it has produced some of the most important original thought, and its contribution to politics, sociology, mathematics, science and literature has been enormous. Although the study of philosophy may not yield "the meaning of life, the universe and everything", many philosophers believe that it is important that each of us examines such questions and some even go as far as claiming that an unexamined life is not worth living. It also provides a good way of learning to think more clearly about a wide range of issues, and its methods of analyzing arguments can be useful in a variety of situations in other areas of life.

Philosophy is such a huge subject that it is difficult to know how to break it down into manageable and logical sections. Perhaps the most basic overall split is geographical, between Eastern Philosophy and Western Philosophy. There are four common ways in which Western Philosophy can be usefully broken down or organized:

• By Branch / Doctrine

• By Historical Period

• By Movement / School

• By Individual Philosophers.

Deleuze: What is Philosophy?

(From: Deleuze/Guttari,1991.)

'The question what is philosophy? can perhaps be posed only late in life, with the arrival of old age and the time for speaking concretely. In fact, the bibliography on the nature of philosophy is very limited. It is a question posed in a moment of quiet restlessness, at midnight, when there is no longer anything to ask. It was asked before; it was always being asked, but too indirectly or obliquely; the question was too artificial, too abstract. Instead of being seized by it, those who asked the question set it out and controlled it in passing. They were not sober enough. There was too much desire to do philosophy to wonder what it was, except as a stylistic exercise. That point of nonstyle where one can finally say, "What is it I have been doing all my life?" had not been reached. There are times when old age produces not eternal youth but a sovereign freedom, a pure necessity in which one enjoys a moment of grace between life and death, and in which all the parts of the machine come together to send into the future a feature that cuts across all ages: Titian, Turner, Monet;'....

Likewise in philosophy, Kant's Critique of Judgment is an unrestrained work of old age, which his successors have still not caught up with: all the mind's faculties overcome their limits, the very limits that Kant had so carefully laid down in the works of his prime.

We cannot claim such a status. Simply, the time has come for us to ask what philosophy is. We had never stopped asking this question previously, and we already had the answer, which has not changed: philosophy is the art of forming, inventing, and fabricating concepts.

But the answer not only had to take note of the question, it had to determine its moment, its occasion and circumstances, its landscapes and personae, its conditions and unknowns. It had to be possible to ask the question "between friends," as a secret or a confidence, or as a challenge when confronting the enemy, and at the same time to reach that twilight hour when one distrusts even the friend. It is then that you say, "That's what it was, but I don't know if I really said it, or if I was convincing enough." And you realize that having said it or been convincing hardly matters because, in any case, that is what it is now....

The Greeks might seem to have confirmed the death of the sage and to have replaced him with philosophers - the friends of wisdom, those who seek wisdom but do not formally possess it. But the difference between the sage and the philosopher would not be merely one of degree, as on a scale: the old oriental sage thinks, perhaps, in Figures, whereas the philosopher invents and thinks the Concept. Wisdom has changed a great deal....

The philosopher is expert in concepts and in the lack of them. He knows which of them are not viable, which are arbitrary or inconsistent, which ones do not hold up for an instant. On the other hand, he also knows which are well formed and attest to a creation, however disturbing or dangerous it may be."

Famous Quotes

• “The unexamined life is not worth living” – Socrates

• “Whereof one cannot speak, thereof one must be silent” – Ludwig Wittgenstein

• “Entities should not be multiplied unnecessarily” – William of Ockham

• “The life of man (in a state of nature) is solitary, poor, nasty, brutish, and short” – Thomas Hobbes

• “I think therefore I am” (“Cogito, ergo sum”) – René Descartes

• “He who thinks great thoughts, often makes great errors” – Martin Heidegger

• “We live in the best of all possible worlds” – Gottfried Wilhelm Leibniz

• “What is rational is actual and what is actual is rational” – G. W. F. Hegel

• “God is dead! He remains dead! And we have killed him.” – Friedrich Nietzsche

• “There is but one truly serious philosophical problem, and that is suicide” – Albert Camus

• “One cannot step twice in the same river” – Heraclitus

• “The greatest happiness of the greatest number is the foundation of morals and legislation” – Jeremy Bentham

• “To be is to be perceived” (“Esse est percipi”)– Bishop George Berkeley

• “Happiness is not an ideal of reason but of imagination” – Immanuel Kant

• “No man's knowledge here can go beyond his experience” – John Locke

• “God is not willing to do everything, and thus take away our free will and that share of glory which belongs to us” – Niccolo Machiavelli

• “Liberty consists in doing what one desires” – John Stuart Mill

• “It is undesirable to believe a proposition when there is no ground whatever for supposing it true” – Bertrand Russell

• “Even while they teach, men learn” – Seneca the Younger

• “There is only one good, knowledge, and one evil, ignorance” – Socrates

• “If God did not exist, it would be necessary to invent Him” – Voltaire

• “This is patently absurd; but whoever wishes to become a philosopher must learn not to be frightened by absurdities” – Bertrand Russell

• “One cannot conceive anything so strange and so implausible that it has not already been said by one philosopher or another” – René Descartes

• “Leisure is the mother of philosophy” – Thomas Hobbes

• “Philosophy is a battle against the bewitchment of our intelligence by means of language” – Ludwig Wittgenstein

• “There is only one thing a philosopher can be relied upon to do, and that is to contradict other philosophers” – William James

• “We are what we repeatedly do. Excellence, then, is not an act, but a habit” – Aristotle

• “Only one man ever understood me, and he didn’t understand me” – G. W. F. Hegel

• “The mind is furnished with ideas by experience alone” – John Locke

• “Life must be understood backward. But it must be lived forward ” – Søren Kierkegaard

• “Science is what you know. Philosophy is what you don't know” – Bertrand Russell

• “Metaphysics is a dark ocean without shores or lighthouse, strewn with many a philosophic wreck” – Immanuel Kant

• “Philosophy is at once the most sublime and the most trivial of human pursuits” – William James

• “History is Philosophy teaching by examples” – Thucydides

• “He who is unable to live in society, or who has no need because he is sufficient for himself, must be either a beast or a god” – Aristotle

• “You can discover more about a person in an hour of play than in a year of conversation” – Plato

• “Things alter for the worse spontaneously, if they be not altered for the better designedly” – Francis Bacon

• “All that is necessary for the triumph of evil is that good men do nothing” – mistakenly attributed to Edmund Burke

• “Is man merely a mistake of God's? Or God merely a mistake of man's?” – Friedrich Nietzsche

• “I would never die for my beliefs because I might be wrong” – Bertrand Russell

• “Religion is the sign of the oppressed ... it is the opium of the people” – Karl Marx

• “Happiness is the highest good” – Aristotle

• “If men were born free, they would, so long as they remained free, form no conception of good and evil” – Baruch Spinoza

• “The greater the difficulty, the more glory in surmounting it” – Epicurus

• “Whatever is reasonable is true, and whatever is true is reasonable” – G. W. F. Hegel

• “Morality is not the doctrine of how we may make ourselves happy, but of how we may make ourselves worthy of happiness” – Immanuel Kant

• “Man is condemned to be free” – Jean-Paul Sartre

• “It is one thing to show a man that he is in error, and another to put him in possession of truth” – John Locke

• “I don’t know why we are here, but I’m pretty sure it is not in order to enjoy ourselves” – Ludwig Wittgenstein

• “That man is wisest who, like Socrates, realizes that his wisdom is worthless” – Plato

• “The only thing I know is that I know nothing” – Socrates

• “All is for the best in the best of all possible worlds” – Voltaire (in parody of Leibniz)

• “The function of prayer is not to influence God, but rather to change the nature of the one who prays” – Søren Kierkegaard

• “Man is born free, but is everywhere in chains” – Jean-Jacques Rousseau

• “Man will never be free until the last king is strangled with the entrails of the last priest” – Denis Diderot

• “If you would be a real seeker after truth, it is necessary that at least once in your life you doubt, as far as possible, all things” – René Descartes

• “Happiness lies in virtuous activity, and perfect happiness lies in the best activity, which is contemplative” – Aristotle

• “I can control my passions and emotions if I can understand their nature” – Spinoza

• “Philosophers have hitherto only interpreted the world in various ways; the point, however, is to change it” – Karl Marx

• “It is wrong always, everywhere and for everyone, to believe anything upon insufficient evidence” – W. K. Clifford

• “Virtue is nothing else than right reason” – Seneca the Younger

• “Freedom is secured not by the fulfilling of one's desires, but by the removal of desire” – Epictetus

• “In everything, there is a share of everything” – Anaxagoras

• “A little philosophy inclineth man's mind to atheism; but depth in philosophy bringeth men’s minds about to religion” – Sir Francis Bacon

• “The brave man is he who overcomes not only his enemies but his pleasures” – Democritus

• “Good and evil, reward and punishment, are the only motives to a rational creature” – John Locke

• “To do as one would be done by, and to love one's neighbour as oneself, constitute the ideal perfection of utilitarian morality” – John Stuart Mill

• “Everything that exists is born for no reason, carries on living through weakness, and dies by accident” – Jean-Paul Sartre

• “Man is the measure of all things” – Protagoras

• “We are too weak to discover the truth by reason alone” – St. Augustine

• “The mind is furnished with ideas by experience alone” – John Locke