Gottlob Frege created modern logic including "for all," "there exists," and rules of proof. Leibniz and Boole had dealt only with what we now call "propositional logic" (that is, no "for all" or "there exists"). They also did not concern themselves with rules of proof, since their aim was to reach truth by pure calculation with symbols for the propositions. Frege took the opposite track: instead of trying to reduce logic to calculation, he tried to reduce mathematics to logic, including the concept of number.

And I myself, in Rome, heard it said openly in the streets, "If there is a hell, then Rome is built on it." That is, "After the devil himself, there is no worse folk than the pope and his followers."

If man puts his honor first in relying upon himself, knowing himself and applying himself, this in self-reliance, self-assertion, and freedom, he then strives to rid himself of the ignorance which makes a strange impenetrable object a barrier and a hindrance to his self-knowledge.

It strikes everyone in beginning to form an acquaintance with the treasures of Indian literature, that a land so rich in intellectual products and those of the profoundest order of thought..."

Life is a business that does not cover the costs.

Is this not an advantage? Is it not a sign of immense progress that the masses should have "ideas," that is to say, should be cultured? By no means. The "ideas" of the average man are not genuine ideas, nor is their possession culture. An idea is a putting truth in checkmate. Whoever wishes to have ideas must first prepare himself to desire truth and to accept the rules of the game imposed by it. It is no use speaking of ideas when there is no acceptance of a higher authority to regulate them, a series of standards to which it is possible to appeal in a discussion. These standards are the principles on which culture rests.

It always seems to me extreme rashness on the part of some when they want to make human abilities the measure of what nature can do. On the contrary, there is not a single effect in nature, even the least that exists, such that the most ingenious theorists can arrive at a complete understanding of it. This vain presumption of understanding everything can have no other basis than never understanding anything. For anyone who had experienced just once the perfect understanding of one single thing, and had truly tasted how knowledge is accomplished, would recognize that of the infinity of other truths he understands nothing.

I cannot live without books.

Liberalism, with its contradictions and compromises, existed for Donoso Cortés only in that short interim period in which it was possible to answer the question "Christ or Barabbas?" with a proposal to adjourn or appoint a commission of investigation.

Good communication is as stimulating as black coffee, and just as hard to sleep after. 

I plead guilty to valuing such a man beyond all other sorts of men. Smooth-shaven Respectabilities not a few one finds, that are not good for much. Small thanks to a man for keeping his hands clean, who would not touch the work but with gloves on!

Good taste is either that which agrees with my taste or that which subjects itself to the rule of reason. From this we can see how useful it is to employ reason in seeking out the laws of taste.

There is certainly some chill and arid knowledge to be found upon the summits of formal and laborious science; but it is all round about you, and for the trouble of looking, that you will acquire the warm and palpitating facts of life.

He who helps the guilty, shares the crime.

Ennui is the echo in us of time tearing itself apart.

The great extension of our experience in recent years has brought light to the insufficiency of our simple mechanical conceptions and, as a consequence, has shaken the foundation on which the customary interpretation of observation was based.

Hypocrisy is a universal phenomenon. It ends with death, but not before.

Love hinders death. Love is life. All, everything that I understand, I understand only because I love. Everything is, everything exists, only because I love. Everything is united by it alone. Love is God, and to die means that I, a particle of love, shall return to the general and eternal source.

He who knows himself properly can very soon learn to know all other men. It is all reflection.

Reason has discovered the struggle for existence and the law that I must throttle all those who hinder the satisfaction of my desires. That is the deduction reason makes. But the law of loving others could not be discovered by reason, because it is unreasonable.

The most beautiful monuments of Athens belong to the century of Pericles. In Rome, what writers were produced under the Republic? Only Plautus and Terence. Lucretius, Sallust, and Cicero saw the Republic die. Then came the century of Augustus when the nation was all that it could be by way of talents. The arts, in general, need a king; they only flourish under the influence of sceptres. Even in Greece, the only country where they flourished in the milieu of a republic, Lysippos and Apelles worked for Alexander. Aristotle owed to Alexander's generosity the means to compose his history of animals; and, after the death of this monarch, the poets, scholars, and artists went to look for protection and rewards in the courts of his successors.

But if ether is nothing but an hypothesis explanatory of light, air on the other hand, is a thing that is directly felt; and even if it did not enable us to explain the phenomenon of sound, we should nevertheless always be directly aware of it, and above all, of the lack of it in moments of suffocation or air-hunger. And in the same way God Himself, not the idea of God, may become a reality that is immediately felt; and even though the idea of God does not enable us to explain either the existence or essence of the Universe, we have at times the direct feeling of God, above all in moments of spiritual suffocation. And the feeling, mark it well, for all that is tragic in it and the whole tragic sense of life is founded upon this - this feeling is a feeling of hunger for God, of the lack of God. To believe in God is, in the first instance... to wish that there may be a God, to be unable to live without Him.

The best is the enemy of the good.

Honour is the mysticism of legality.

Out of love, God becomes man. He says: Here you see what it is to be a human being; but he adds: Take care, for I am also God - blessed is he who takes no offense at me. 

Whenever the therapist stands with society, he will interpret his work as adjusting the individual and coaxing his 'unconscious drives' into social respectability. But such 'official psychotherapy' lacks integrity and becomes the obedient tool of armies, bureaucracies, churches, corporations, and all agencies that require individual brainwashing. On the other hand, the therapist who is really interested in helping the individual is forced into social criticism. This does not mean that he has to engage directly in political revolution; it means that he has to help the individual in liberating himself from various forms of social conditioning, which includes liberation from hating this conditioning - hatred being a form of bondage to its object.

To teach him betimes to love and be good-natur'd to others, is to lay early the true foundation of an honest man; all injustice generally springing from too great love of ourselves and too little of others.

Live among men as if God beheld you; speak with God as if men were listening.

It is often better for a person to recognize a sin than to do a good deed. Recognizing a sin makes a person humble. Doing a good deed often can feed a person's pride.

The habits of study acquired at Universities are of the highest importance in after-life. At the season when you are in young years the whole mind is, as it were, fluid, and is capable of forming itself into any shape that the owner of the mind pleases to order it to form itself into. The mind is in a fluid state, but it hardens up gradually to the consistency of rock or iron, and you cannot alter the habits of an old man, but as he has begun he will proceed and go on to the last.

It is the same thing: killing, dying, it is the same thing: one is just as alone in each. He is lucky, he will only die once. As for me, for ten days I have been killing him at every minute. Hugo to Jessica, on his plans to kill.

Use, do not abuse; as the wise man commands. I flee Epictetus and Petronius alike. Neither abstinence nor excess ever renders man happy.

The Americans have always been more open to my ideas. In fact, I could earn a living in America just by lecturing. One of my brightest audiences, incidentally, were the prisoners in a Philadelphia gaol - brighter than my students at university.

Technically speaking, since our complex societies are highly susceptible to interferences and accidents,they certainly offer ideal opportunities for a prompt disruption of normal activities. These disruptions can, with minimum expense, have considerably destructive consequences. Global terrorism is extreme both in its lack of realistic goals and in its cynical exploitation of the vulnerability of complex systems.

In fact of course, this 'productive' worker cares as much about the crappy shit he has to make as does the capitalist himself who employs him, and who also couldn't give a damn for the junk.

Machiavelli is the complete contrary of a machiavellian, since he describes the tricks of power and "gives the whole show away." The seducer and the politician, who live in the dialectic and have a feeling and instinct for it, try their best to keep it hidden.

Every nation gets the government it deserves.

You could leave life right now. Let that determine what you do and say and think.

This is the pure form of servitude: to exist as an instrument.

Generosity is nothing else than a craze to possess. All which I abandon, all which I give, I enjoy in a higher manner through the fact that I give it away.... To give is to enjoy possessively the object which one gives.

A man of intellect is like an artist who gives a concert without any help from anyone else, playing on a single instrument - a piano, say, which is a little orchestra in itself. Such a man is a little world in himself; and the effect produced by various instruments together, he produces single-handed, in the unity of his own consciousness. Like the piano, he has no place in a symphony; he is a soloist and performs by himself - in solitude, it may be; or if in the company with other instruments, only as principal; or for setting the tone, as in singing.

It is, they say, not Russia that plans aggression but, on the contrary, the decaying capitalist democracies. Russia wants merely to defend its own independence. This is an old and well-tried method of justifying aggression. Louis XIV and Napoleon I, Wilhelm II and Hitler were the most peace-loving of all men. When they invaded foreign countries, they did so only in just self-defence. Russia was as much menaced by Estonia or Latvia as Germany was by Luxemburg or Denmark.

To live life well is to express life poorly; if one expresses life too well, one is living it no longer.

There are those who blame the Press, but in this I think they are mistaken. The Press is such as the public demands, and the public demands bad newspapers because it has been badly educated.