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)

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)

The world and life are one. (5.621)

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)

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

What cannot be imagined cannot even be talked about.

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)

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

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

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

But ordinary language is all right.

The difficulty in philosophy is to say no more than we know.

To convince someone of the truth, it is not enough to state it, but rather one must find the path from error to truth.

I must plunge into the water of doubt again and again.

Frazer's account of the magical and religious views of mankind is unsatisfactory; it makes these views look like errors.

Every explanation is after all an hypothesis.

A religious symbol does not rest on any opinion. And error belongs only with opinion. One would like to say: This is what took place here; laugh, if you can.

Burning in effigy. Kissing the picture of one's beloved... it aims at nothing at all; we just behave this way and then we feel satisfied.

The ceremonial (hot or cold) as opposed to the haphazard (lukewarm) characterizes piety.

What should we gain by a definition, as it can only lead us to other undefined terms?

For remember that in general we don't use language according to strict rules — it hasn't been taught us by means of strict rules, either.

The idea that in order to get clear about the meaning of a general term one had to find the common element in all its applications has shackled philosophical investigation; for it has not only led to no result, but also made the philosopher dismiss as irrelevant the concrete cases, which alone could have helped him understand the usage of the general term.

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)

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

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)

There are, indeed, things that cannot be put into words. They make themselves manifest. They are what is mystical. (6.522)

My propositions are elucidatory in this way: he who understands me finally recognizes them as senseless, when he has climbed out through them, on them, over them. (He must so to speak throw away the ladder, after he has climbed up on it.) (6.54)

A proposition is completely logically analyzed if its grammar is made completely clear: no matter what idiom it may be written or expressed in...

What I give is the morphology of the use of an expression. I show that it has kinds of uses of which you had not dreamed. In philosophy one feels forced to look at a concept in a certain way. What I do is suggest, or even invent, other ways of looking at it. I suggest possibilities of which you had not previously thought. You thought that there was one possibility, or only two at most. But I made you think of others. Furthermore, I made you see that it was absurd to expect the concept to conform to those narrow possibilities. Thus your mental cramp is relieved, and you are free to look around the field of use of the expression and to describe the different kinds of uses of it.

Tell them I've had a wonderful life.

(About Jesus) If He did not rise again, then He rotted in the grave like any other human being. He died and his body rotted.

We must plow through the whole of language.

115. If you tried to doubt everything you would not get as far as doubting anything. The game of doubting itself presupposes .

Freud's fanciful pseudo-explanations (precisely because they are brilliant) perform a disservice. (Now any ass has these pictures available to use in "explaining" symptoms of an illness.

I would really like to slow down the speed of reading with continual punctuation marks. For I would like to be read slowly. (As I myself read.)

Nothing is more important than the formation of fictional concepts, which teach us at last to understand our own.

If a false thought is so much as expressed boldly and clearly, a great deal has already been gained.

Human beings have a physical need to tell themselves when at work: “Let’s have done with it now,” and it's having constantly to go on thinking in the face of this need when philosophizing that makes this work so strenuous.