Heidegger constantly, isolated in a house in the forest where He spent time with him and with his family. In these stays outside the hectic civilization, Heidegger would begin to work on which could be considered his masterpiece: being and time. Being and time is a great influence for modern Existentialism and thinkers and literary figures such as Jean-Paul Sartre. It is said there that Heidegger is an intellectual who changes the way of seeing things, either positively or negatively, or it is accepted or rejected, after Heidegger thought is another. This phenomenon is observed his work, where Heidegger expresses a strong criticism of Phenomenology, the work famous of his teacher Husserl, to such an extent that it almost dismantled the idea completely. Still, being and time builds an even more revolutionary idea about the very existence of the human being.
It speaks of being as verb and noun; one questions the true meaning of the action of be where arises as to what is what it really means to be? Or, as Heidegger puts it, we are leaving we carry by the conventionality of the word? These questions place us in an intellectual predicament to get closer to the opposition to say: we have the degree of existence that we understand as the simple action of be here or we can find this misunderstood verb relationship with other factors of the human dimension? For Heidegger, time was this direct link with the being and the canvas on which began to sketch the existence. Thus, Heidegger questioned the significance of space as a determinant of our existence; i.e., leave aside the conception of the Cartesian coordinates where the tangible body can be found and searches the place that occupies that which transcends these physical barriers. Being, therefore, is a process of change, a process of becoming into something more: a constant change.