"The only thing necessary for the triumph of evil is for good people to do nothing."
--- Edmund Burke

"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

"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 neighbor 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