Ambition is the death of thought.

I am showing my pupils details of an immense landscape which they cannot possibly know their way around.

Don't for heaven's sake, be afraid of talking nonsense! But you must pay attention to your nonsense.

One might say: art shows us the miracles of nature. It is based on the concept of the miracles of nature.

You could attach prices to ideas. Some cost a lot some little. ... And how do you pay for ideas? I believe: with courage.

If life becomes hard to bear we think of improvements. But the most important and effective improvement, in our own attitude, hardly occurs to us, and we can decide on this only with the utmost difficulty.

Someone who knows too much finds it hard not to lie.

Animals come when their names are called. Just like human beings.

Is it just I who cannot found a school, or can a philosopher never do so?

Schiller writes in a letter [to Goethe, 17 December 1795] of a ‘poetic mood’. I think I know what he means, I think I am familiar with it myself. It is the mood of receptivity to nature and one in which one's thoughts seem as vivid as nature itself.

It's only by thinking even more crazily than philosophers do that you can solve their problems.

Never stay up on the barren heights of cleverness, but come down into the green valleys of silliness.

You must always be puzzled by mental illness. The thing I would dread most, if I became mentally ill, would be your adopting a common sense attitude; that you could take it for granted that I was deluded.

Die Philosophie ist ein Kampf gegen die Verhexung unsres Verstandes durch die Mittel unserer Sprache.

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.

It is so characteristic, that just when the mechanics of reproduction are so vastly improved, there are fewer and fewer people who know how the music should be played.

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.

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

The thought is the significant proposition. (4)

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)

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

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)

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

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

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

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)

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)

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

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

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.

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 world is all that is the case. (1)

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

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