I shall develop the thesis that anyone acting communicatively must, in performing any speech act, raise universal validity claims and suppose that they can be vindicated.

He is a despicable sage whose wisdom does not profit himself.

He knows his own strength; he knows that he was born to carry burdens.

I cleave the heavens and soar to the infinite. And while I rise from my own globe to others And penetrate ever further through the eternal field, That which others saw from afar, I leave far behind me. Variant translation: While I venture out beyond this tiny globe Into reaches past the bounds of starry night I leave behind what others strain to see afar.

We favor hypotheses for their simplicity and explanatory power, much as the architect of the world might have done in choosing which possibility to create.

An appeal to his alarm is never a good plan to rid oneself of a spirited young man.

In art the Chinese aim at being exquisite, and in life at being reasonable.

The ideal of strictly scientific method in mathematics which I have tried to realise here, and which perhaps might be named after Euclid I should like to describe in the following way... The novelty of this book does not lie in the content of the theorems but in the development of the proofs and the foundations on which they are based... With this book I accomplish an object which I had in view in my Begriffsschrift of 1879 and which I announced in my Grundlagen der Arithmetik. I am here trying to prove the opinion on the concept of number that I expressed in the book last mentioned.

Jung believed that he was proceeding scientifically, but most Freudians remain convinced that he was inventing his own underground realm, rather as Tolkien invented Middle Earth. There is at least an element of truth in this view.

Wise people are in want of nothing, and yet need many things. On the other hand, nothing is needed by fools, for they do not understand how to use anything, but are in want of everything.

If wandering is the liberation from every given point in space, and thus the conceptional opposite to fixation at such a point, the sociological form of the "stranger" presents the unity, as it were, of these two characteristics.

If one's organism is... the preeminent advantage, and the source of all others, education is the second. The best made brain would be a total loss without it...

Progress, far from consisting in change, depends on retentiveness. When change is absolute there remains no being to improve and no direction is set for possible improvement: and when experience is not retained, as among savages, infancy is perpetual. Those who cannot remember the past are condemned to repeat it. This famous statement has produced many paraphrases and variants: Those who cannot learn from history are doomed to repeat it. Those who do not remember their past are condemned to repeat their mistakes. Those who do not read history are doomed to repeat it. Those who fail to learn from the mistakes of their predecessors are destined to repeat them. Those who do not know history's mistakes are doomed to repeat them.

Liberty therefore not being more fit than other words in some of the instances in which it has been used, and not so fit in others, the less the use that is made of it the better. I would no more use the word liberty in my conversation when I could get another that would answer the purpose, than I would brandy in my diet, if my physician did not order me: both cloud the understanding and inflame the passions.

Beyond all conscious lying and falsifying, there is a deeper "organic mendacity." Here the falsification is not formed in consciousness, but at the same stage of the mental process as the impressions and value feelings themselves: on the road of experience into consciousness. There is "organic mendacity" whenever a man's mind admits only those impressions which serve his "interest" or his instinctive attitude. Already in the process of mental reproduction and recollection, the contents of his experience are modified in this direction. He who is "mendacious" has no need to lie! In his case, the automatic process of forming recollections, impressions, and feelings is involuntarily slanted, so that conscious falsification becomes unnecessary.

I sit astride life like a bad rider on a horse. I only owe it to the horse's good nature that I am not thrown off at this very moment.

There are some mixt bodies, from which it has not been yet made appear, that any degree of fire can separate either salt, or sulphur, or mercury, much less all the three. The most obvious instance of this truth is gold, which is a body so fixed, and wherein the elementary ingredients (if it have any) are so firmly united to each other, that we find not in the operations, wherein gold is exposed to the fire, how violent soever, that it does discernably so much as lose of its fixedness or weight, so far is it from being dissipated into those principles, whereof one at least is acknowledged to be fugitive enough.

In order to succeed, we must first believe that we can.

What is it that we humans depend on? We depend on our words... Our task is to communicate experience and ideas to others. We must strive continually to extend the scope of our description, but in such a way that our messages do not thereby lose their objective or unambiguous character ... We are suspended in language in such a way that we cannot say what is up and what is down. The word "reality" is also a word, a word which we must learn to use correctly.

If God holds all mankind guilty for the sin of Adam, if he has visited upon the innocent the punishment of the guilty, if he is to torture any single soul for ever, then it is wrong to worship him.

It is the mark of a good action that it appears inevitable in the retrospect. We should have been cut-throats to do otherwise. And there's an end. We ought to know distinctly that we are damned for what we do wrong; but when we have done right, we have only been gentlemen, after all. There is nothing to make a work about.

Being is only Being for Dasein.

Such is the content of the mental life of the Hemingway hero and the good guy in general. Every day he gets beaten into a servile pulp by his own mechanical reflexes, which are constantly busy registering and reacting to the violent stimuli which his big, noisy, kinesthetic environment has provided for his unreflective reception.

There is much pleasure to be gained from useless knowledge.

The issue over there being classes seems more a question of convenient conceptual scheme; the issue over there being centaurs, or brick houses on Elm Street, seems more a question of fact. But I have been urging that this difference is only one of degree, and that it turns upon our vaguely pragmatic inclination to adjust one strand of the fabric of science rather than another in accommodating some particular recalcitrant experience. Conservatism figures in such choices, and so does the quest for simplicity.

If you would not have a man flinch when the crisis comes, train him before it comes.

Behind all appearances, I divine a struggling essence. I want to merge with it. I feel that behind appearances this struggling essence is also striving to merge with my heart. But the body stands between us and separates us. The mind stands between us and separates us.

In all cases, therefore, we will agree with the judicious Mrs. Glass: 'First catch your hare!' First get your man; all is got: he can learn to do all things, from making boots, to decreeing judgments, governing communities; and will do them like a man.

He has begun by supposing that light has a constant velocity... the same in all directions. This... could never be verified directly by experiment... The postulate... resembling the principle of sufficient reason... furnishes us with a new rule for the investigation of simultaneity.

It is important that man dreams, but it is perhaps equally important that he can laugh at his own dreams.

As for me, I am mean: that means that I need the suffering of others to exist. A flame. A flame in their hearts. When I am all alone, I am extinguished.

O poor mortals, how ye make this earth bitter for each other.

Philosophers today are as fond as ever of apriori arguments with ethical conclusions. One reason such arguments are always unsatisfying is that they always prove too much; when a philosopher 'solves' an ethical problem for one, one feels as if one had asked for a subway token and been given a passenger ticket valid for the first interplanetary passenger-carrying space ship instead.

I think television has betrayed the meaning of democratic speech, adding visual chaos to the confusion of voices. What role does silence have in all this noise?

I have no need to take up each thing that wants to throw its cause on us and show that it is occupied only with itself, not with us, only with its good, not with ours. Look at the rest for yourselves. Do truth, freedom, humanity, justice, desire anything else than that you grow enthusiastic and serve them?

We define only out of despair, we must have a formula... to give a facade to the void.

Timid men prefer the calm of despotism to the tempestuous sea of liberty.

For I now saw, or thought I saw, what I had always before received with incredulity-that the habit of analysis has a tendency to wear away the feelings: as indeed it has, when no other mental habit is cultivated, and the analysing spirit remains without its natural complements and correctives.

Nothing great has great beginnings.

All true metaphysics is taken from the essential nature of the thinking faculty itself, and therefore in nowise invented, since it is not borrowed from experience, but contains the pure operations of thought, that is, conceptions and principles à priori, which the manifold of empirical presentations first of all brings into legitimate connection, by which it can become empirical knowledge, i.e. experience. ...mathematical physicists were thus quite unable to dispense with such metaphysical principles...

I was your luxury. For nineteen years I have been put in your man's world and was forbidden to touch anything and you made me think that all was going very well and that I did not have to worry about anything but putting flowers in vases. Why did you lie to me? Why did you keep me ignorant, if it was to admit to me one day that this world is cracking and that you are all powerless and to make me choose between a suicide and a murder?

Every man takes the limits of his own field of vision for the limits of the world.

What the learned world tends to offer is one second-hand scrap of information illustrating ideas derived from another second-hand scrap of information. The second-handedness of the learned world is the secret of its mediocrity.

Some part of life - perhaps the most important part - must be left to the spontaneous action of individual impulse, for where all is system there will be mental and spiritual death.

The really important facts were that spatial relationships had ceased to matter very much and that my mind was perceiving the world in terms of other than spatial categories. At ordinary times the eye concerns itself with such problems as where? - how far? - how situated in relation to what? In the mescaline experience the implied questions to which the eye responds are of another order. Place and distance cease to be of much interest. The mind does its perceiving in terms of intensity of existence, profundity of significance, relationships within a pattern."

Such delusions of grandeur to think that a God with a hundred billion galaxies on his mind would give a tuppenny damn who you sleep with, or indeed whether you believe in him.

As one advances in life, one realises more and more that the majority of men - and of women - are incapable of any other effort than that strictly imposed on them as a reaction to external compulsion. And for that reason, the few individuals we have come across who are capable of a spontaneous and joyous effort stand out isolated, monumentalised, so to speak, in our experience. These are the select men, the nobles, the only ones who are active and not merely reactive, for whom life is a perpetual striving, an incessant course of training. Training = askesis. These are the ascetics.

Of our desires some are natural and necessary, others are natural but not necessary; and others are neither natural nor necessary, but are due to groundless opinion.

It is hard to imagine an experience more horrific than being eaten alive. Most of us would prefer not to imagine what it must feel like. Note that the photographer here had to persuade the park ranger to violate the park rules and put the baby elephant out of his misery.By analogy, suppose it were lawful to visit Third World countries for photoshoots but illegal to "interfere" and help a stricken human baby. Is there a fundamental difference between "ethical" intervention to help humans and "sentimental" pleas to "interfere" and help non-humans? Should we encourage the preservation of life-forms such as the hyena in their current guise? Or do the value judgements underlying the "science" of conservation biology need to be re-examined?