"Scepticism is not irrefutable, but obviously nonsensical, when it tries to raise doubts where no questions can be asked. For doubt can exist only where a question exists, a question only where an answer exists, and an answer only where something can be said. (6.51)"

"It is not how things are in the world that is mystical, but that it exists. (6.44)"

"Death is not an event in life: we do not live to experience death. If we take eternity to mean not infinite temporal duration but timelessness, then eternal life belongs to those who live in the present. Our life has no end in just the way in which our visual field has no limits. (6.4311)"

"The world of the happy is quite different from the world of the unhappy. (6.43)"

"The subject does not belong to the world, but it is a limit of the world. (5.632)"

"I am my world. (The microcosm.) (5.63)"

"The world and life are one. (5.621)"

"This remark provides the key to the problem, how much truth there is in solipsism. For what the solipsist means is quite correct; only it cannot be said, but makes itself manifest. The world is my world: this is manifest in the fact that the limits of language (of that language which alone I understand) mean the limits of my world. (5.62)"

"Logic pervades the world: the limits of the world are also its limits. So we cannot say in logic, "The world has this in it, and this, but not that." For that would appear to presuppose that we were excluding certain possibilities, and this cannot be the case, since it would require that logic should go beyond the limits of the world; for only in that way could it view those limits from the other side as well. We cannot think what we cannot think; so what we cannot think we cannot say either. (5.61)"

"The limits of my language mean the limits of my world. (5.6)"

"If I cannot say a priori what elementary propositions there are, then the attempt to do so must lead to obvious nonsense. (5.5571)"

"Propositions are truth-functions of elementary propositions. (An elementary proposition is a truth-function of itself.) (5)"

"A tautology's truth is certain, a proposition's possible, a contradiction's impossible. (Certain, possible, impossible: here we have the first indication of the scale that we need in the theory of probability.) (4.464)"

"It is quite impossible for a proposition to state that it itself is true. (4.442)"

"Philosophy aims at the logical clarification of thoughts. Philosophy is not a body of doctrine but an activity. A philosophical work consists essentially of elucidations. Philosophy does not result in 'philosophical propositions', but rather in the clarification of propositions. Without philosophy thoughts are, as it were, cloudy and indistinct: its task is to make them clear and to give them sharp boundaries. (4.112)"

"The thought is the significant proposition. (4)"

"Though a state of affairs that would contravene the laws of physics can be represented by us spatially, one that would contravene the laws of geometry cannot. (3.0321)"

"The logical picture of the facts is the thought. (3)"

"What is the case, the fact, is the existence of atomic facts. (2)"

"The world is the totality of facts, not things. (1.1)"

"The world is all that is the case. (1)"

"The whole sense of the book might be summed up the following words: what can be said at all can be said clearly, and what we cannot talk about we must pass over in silence."

"The aim of the book is to set a limit to thought, or rather — not to thought, but to the expression of thoughts: for in order to be able to set a limit to thought, we should have to find both sides of the limit thinkable (i.e. we should have to be able to think what cannot be thought). It will therefore only be in language that the limit can be set, and what lies on the other side of the limit will simply be nonsense."

"Don’t get involved in partial problems, but always take flight to where there is a free view over the whole single great problem."

"It is clear that the causal nexus is not a nexus at all."

"What cannot be imagined cannot even be talked about."

"It is true: Man is the microcosm: I am my world."

"The World and Life are one. Physiological life is of course not "Life". And neither is psychological life. Life is the world. Ethics does not treat of the world. Ethics must be a condition of the world, like logic. Ethics and Aesthetics are one."

"There are two godheads: the world and my independent I. I am either happy or unhappy, that is all. It can be said: good or evil do not exist. A man who is happy must have no fear. Not even in the face of death. Only a man who lives not in time but in the present is happy."

"To believe in a God means to understand the question about the meaning of life. To believe in a God means to see that the facts of the world are not the end of the matter. To believe in God means to see that life has a meaning."

"What do I know about God and the purpose of life? I know that this world exists. That I am placed in it like my eye in its visual field. That something about it is problematic, which we call its meaning. This meaning does not lie in it but outside of it. That life is the world. That my will penetrates the world. That my will is good or evil. Therefore that good and evil are somehow connected with the meaning of the world. The meaning of life, i.e. the meaning of the world, we can call God. And connect with this the comparison of God to a father. To pray is to think about the meaning of life."

"Certainly it is correct to say: Conscience is the voice of God."

"One of the most difficult of the philosopher's tasks is to find out where the shoe pinches."

"Language is a part of our organism and no less complicated than it."

"It is one of the chief skills of the philosopher not to occupy himself with questions which do not concern him."

"I cannot get from the nature of the proposition to the individual logical operations!!! That is, I cannot bring out how far the proposition is the picture of the situation. I am almost inclined to give up all my efforts. ——"

"My difficulty is only an — enormous — difficulty of expression."

"Don't get involved in partial problems, but always take flight to where there is a free view over the whole single great problem, even if this view is still not a clear one."

"Logic takes care of itself; all we have to do is to look and see how it does it."

"One often makes a remark and only later sees how true it is."

""It is necessary to be given the prop that all elementary props are given." This is not necessary because it is even impossible. There is no such prop! That all elementary props are given is SHOWN by there being none having an elementary sense which is not given."

"You won't — I really believe — get too much out of reading it. Because you won't understand it; the content will seem strange to you. In reality, it isn't strange to you, for the point is ethical. I once wanted to give a few words in the foreword which now actually are not in it, which, however, I'll write to you now because they might be a key for you: I wanted to write that my work consists of two parts: of the one which is here, and of everything which I have not written. And precisely this second part is the important one."

"I work quite diligently and wish that I were better and smarter. And these both are one and the same."

"It seems to me as good as certain that we cannot get the upper hand against England. The English — the best race in the world — cannot lose! We, however, can lose and shall lose, if not this year then next year. The thought that our race is going to be beaten depresses me terribly, because I am completely German."

"Well, God has arrived. I met him on the 5:15 train. He has a plan to stay in Cambridge permanently."

"Three years after Einstein’s General Theory of Relativity was verified by Eddington, ending belief in fixed space and time, Ludwig Wittgenstein, one of the key figures of our period, published his Tractatus Logico-Philosophicus, which cumulatively over the decades tended to destroy confidence in philosophy as a guide to human reason. For half a century Wittgenstein’s influence on academic philosophy was immense. By the early 1990s doubts were raised about his sanity: was he a genius, or simply a madman? But by then much damage had been done. A leading Logical Positivist like Sir A.J. Ayer, who at the time of his death in 1989 was widely regarded as the world’s leading philosopher, remarked with some complacency that philosophy demonstrated that man was ignorant rather than knowledgeable: ‘[It] tends to show that we can’t really know lots of things which we think we know.’ Empirical popular knowledge, usually termed ‘common sense’, had been dismissed contemptuously by Bertrand Russell as ‘the metaphysics of savages’."

"He was like an atomic bomb, a tornado — people don't appreciate that."

"What struck me most in this conversation was a radical passion for truthfulness in everything (which I came to know as a characteristic vogue among the young Viennese intellectuals of the generation immediately preceding mine only in the following university years). This truthfulness became almost a fashion in that border group between the purely Jewish and the purely Gentile parts of the intelligentsia in which I came so much to move. It meant much more than truth in speech. One had to "live" truth and not tolerate any pretence in oneself or others. It sometimes produced outright rudeness and, certainly, unpleasantness. Every convention was dissected and every conventional form exposed as fraud. Wittgenstein merely carried this further in applying it to himself. I sometimes felt that he took a perverse pleasure in discovering falsehood in his own feelings and that he was constantly trying to purge himself of all fraud."

"Wittgenstein was right when he said that the limits of our world are identical with the limits of our language, and, I would add, there is on an everyday level clear interaction between one's language and one's patterns of thought."