I talked in my first blog entry about Heidegger's attempt to destroy our standard, traditional philosophical vocabulary and replace it with something new. What Heidegger seeks to destroy in particular is a certain picture of the relation between human beings and the world that is widespread in modern philosophy and whose source is Descartes (indeed Descartes is the philosopher who stands most accused in Being and Time). Roughly and readily, this is the idea that there are two sorts of substances in the world: thinking things like us and extended things, like tables, chairs and indeed the entire fabric of space and time.

The relation between thinking things and extended things is one of knowledge and the philosophical and indeed scientific task consists in ensuring that what a later tradition called "subject" might have access to a world of objects. This is what we might call the epistemological construal of the relation between human beings and the world, where epistemology means "theory of knowledge". Heidegger does not deny the importance of knowledge, he simply denies its primacy. Prior to this dualistic picture of the relation between human beings and the world lies a deeper unity that he tries to capture in the formula "Dasein is being-in-the-world". What might that mean?