Quotes About Logic

Ludwig Wittgenstein

Roughly speaking: to say of two things that they are identical is nonsense, and to say of one thing that it is identical with itself is to say nothing.

Superstition is the belief in the causal nexus.

The agreement or disagreement or its sense with reality constitutes its truth or falsity.

The sole remaining task for philosophy is the analysis of language.

Bad philosophers are like slum landlords. It's my job to put them out of business.

All numbers in logic must be capable of justification.   Or rather it must become plain that there are no numbers in logic.   There are no pre-eminent numbers.

For remember that in general we don't use language according to strict rules-- it hasn't been taught to us by means of strict rules, either. We, in our discussions on the other hand, constantly compare language with a calculus preceding to exact rules.

I want to say: We use judgements as principlesof judegement.

Reading the Socratic dialogues one has the feeling: what a frightful waste of time! What's the point of these arguments that prove nothing and clarify nothing?

For philosophical problems arise when language goes on holiday.

What is the use of studying philosophy if all that it does for you is to enable you to talk with some plausibility about some abstruse questions of logic, etc., & if it does not improve your thinking about the important questions of everyday life, if it does not make you more conscientious than any ... journalist in the use of the DANGEROUS phrases such people use for their own ends.

But all propositions of logic say the same thing. That is, nothing.

The solution of logical problems must be neat for they set the standard of neatness.

Most propositions and questions, that have been written about philosophical matters, are not false, but senseless. ... (They are of the same kind as the question whether the Good is more or less identical than the Beautiful.)

We cannot therefore say in logic: This and this there is in the world, that there is not. For that would apparently presuppose that we exclude certain possibilities, and this cannot be the case since otherwise logic must get outside the limits of the world: that is, if it could consider these limits from the other side also.

There is no such thing as an isolated proposition. For what I call a proposition is a position in the game of language.

The book deals with the problems of philosophy and shows, as I believe, that the method of formulating these problems rests on the misunderstanding of the logic of our language.

Self-evidence, of which Russell has said so much, can only be discarded in logic by language itself preventing every logical mistake. That logic is a priori consists in the fact that we cannot think illogically.

The gramophone record, the musical thought, the score, the waves of sound, all stand to one another in that pictorial internal relation, which holds between language and the world. To all of them the logical structure is common. (Like the two youths, their two horses and their lilies in the story. They are all in a certain sense one.)

But doesn't it come out here that knowledge is related to a decision?

It used to be said that God could create anything except what would be contrary to the laws of logic. The truth is that we could not say what an illogical world would look like.

Any serious philosophy can be described entirely through jokes.

At the end of reasons comes persuasion.