Se trata de lo que podríamos llamar la vivencia de sentirse absolutamente seguro. Me refiero a aquel estado anímico en el que nos sentimos inclinados… - Ludwig Wittgenstein

The sense of a truth-function of p is a function of the sense of p. Denial, logical addition, logical multiplication, etc. etc., are operations. (Denial reverses the sense of a proposition.)

The object of philosophy is the logical clarification of thoughts. Philosophy is not a theory but an activity. A philosophical work consists essentially of elucidations.

This book is written for such men as are in sympathy with its spirit. This spirit is different from the one which informs the vast stream of European and American civilization in which all of us stand. The spirit expresses itself in an onwards movement, building ever larger and more complicated structures; the other in striving after clarity and perspicuity in no matter what structure. The first tries to grasp the world by way of its periphery — in its variety; the second at its center — in its essence. And so the first adds one construction to another, moving on and up, as it were, from one stage to the next, while the other remains where it is and what it tries to grasp is always the same.