"Philosophical Investigations" by Ludwig Wittgenstein,1953

..
Language is best conceived as an activity involving the uses of words as tools.
.
Words are used in a multiplicity of ways and are to be understood by engaging in the language "games" in which they are employed ; words are not labels for things.
.
For a large number of cases in which the word "meaning" is used,
the meaning of a word is its use in the language.
.
Discourse about sensations is understandable because there is a grammar of the word "sensations",and of such words as "pain" and "remember",which can be grasped by anyone acquainted with the relevant language games ;
no reference to what one has in mind or feels privately makes sense unless it makes in this way.
.
Expecting,intending,remembering
-these are ways of life made possible by the use of language ;
and language is itself a way of life.
..

"Being and Time" by Martin Heidegger,1927

..
The world,existentially and phenomenologically understood,
is a region of human concern ;
man is being-in-the-world,in that by participation and involvement the world becomes constitutive of man's being.
.
Man has being in an environment ;
and his world is a world he shares with others.
.
Man is a creature of concerns ;
in relation to environment,his concerns are practical ;
in relation to the communal world,his concerns are personal.
.
The three fundamental features of man are :
factuality -he is already involved in the world-,
existence-iality -he is a project and a possibility,that which has been,but also that which can become-,and
fallenness -he has the tendency to become has a mere in the world,failing to make the most of his possibilities because of gossip,curiosity,and ambiguity-.
.
Through anxiety man encounters nothingness and becomes aware of his finitude and the necessity of death ; but through resolution man,who moves in time from past to future through the present,appraises himself,chooses with the whole of his being,and thereby achieves authentic existence.
..

"Tractatus Logico-Philosophicus" by Ludwig Wittgenstein,1921

..
The world is made up of atomic facts ;
atomic facts are facts which are incapable of analysis into more elemental facts.
.
Propositions are logical pictures of -possible- facts ;
what is common to a proposition and the fact it pictures is logical structure.
.
A proposition does not express the form of a possible fact ; it shows it.
.
To give the general form of proposition is to give the essence of all description and of the world ; any proposition whatsoever can be formed by drawing from the class of elementary propositions and using various logical operations.
.
Philosophy is a process of clarification ;
the propositions of natural science are meaningful,
but the attempt to say something meaningful in ethics,aesthetics,
or metaphysics is bound to fail,
for any such attempt involves the impossible task of talking about the world from the outside.
..