Concept of world in Being and Time

While the German philosopher Heidegger has made Being the main issue of philosophy with the thesis that it is possible to ask the question of the meaning of being only through questioning the concept of the world, he also put forward a very different conception of the world from the deffinitions of the world up until that time. According to the constructivist philosophy, the subject that constructs the beings himself/herself, according to Heidegger, is human, the only being in which Being reveals itself and understands Being. Human exists by understanding Being. This is why Heidegger calls human Dasein. Therefore, the search for the meaning of Being necessitates the search for Dasein existence. The main existential mode of Dasein is Being-in-the-World. Just as Dasein cannot exist apart from the world, the world cannot exist without Dasein. Heidegger states that without Dasein, not other beings, the "world" would not exist. This is a very important starting point for comprehending his world understanding. In this thesis, the world, that Heidegger regards as a phenomenon in Being and Time, will be revealed by examining his four definitions about the world under separate headings. The third and fourth definitions which are peculiar to Heidegger, the surrounding world and the worldliness of the world, are in the focus of the thesis. Keywords: Dasein, World, Being, Beings, Being-in-the-World, Surrounding World, Worldliness