Overview
Indeed, the question which was raised long ago, is still and always will be, and which always baffles us—"What is Being?"
Aristotle, Metaphysics 1028b
Overview
Being and Time (Sein und Zeit) is Martin Heidegger’s magnum opus and is widely considered a key document of existentialist philosophy.
Published in 1927 when Heidegger was thirty-six years old, the book represents an intensive effort to bring together a number of seemingly conflicting intellectual traditions, including, among others, those of the pre-Socratic philosophers, Aristotle, Augustine, Luther, Kant, Hegel, Kierkegaard, Nietzsche, Bergson, and Husserl.
The account presented in Being and Time stands in stark opposition to one of the central assumptions of mainstream Western philosophy: the assumption that Being must be thought of as something permanent and unchanging. Whereas most philosophers since Plato have assumed that the Being of anything must be understood in terms of what is eternal and fixed (Forms, essences, scientific laws, etc.), Heidegger suggests that Being is temporal unfolding; indeed, it is time itself. As Heidegger only finished half of Being and Time, it’s unclear how he envisaged the final connection between Being and time.
The book revived the study of ontology through an analysis of what Heidegger referred to as Dasein, or "being-in-the-world." It's also noted for an array of neologisms and complex language, as well as an extended treatment of "authenticity" as a means to grasp and confront the unique and finite possibilities of the individual.
Being and Time had a notable impact on subsequent philosophy, psychology, literary theory, and many other fields. Its stature in intellectual history has been compared with works by Descartes, Kant, and Hegel.
The extreme density of the text is due in part to Heidegger’s avoidance of traditional philosophical terminology in favor of neologisms derived from colloquial German, most notably Dasein (literally, “being-there”). Heidegger uses this technique to further his goal of dismantling traditional philosophical theories and perspectives.
Background
Being and Time can be read as a response to the dominant theory of knowledge in modern philosophy since René Descartes (1596–1650). Most influential thinkers in early 20th-century Germany, the neo-Kantians and positivists, were trying to establish a secure foundation for knowledge of the world on the basis of phenomena or experiences about which the knower could be certain. That approach presupposed a conception of the individual as a mere thinking subject (or “thinking substance”) who is radically distinct from the world and therefore cognitively isolated from it.
Heidegger set aside questions about knowledge and turned directly to an examination of the Being of entities. For Heidegger, the very Being of the individual involves engagement with the world. The fundamental character of Dasein is a condition of already “Being-in-the-world”—of already being caught up in, involved with, or committed to other individuals and things. Dasein’s practical involvements and commitments, therefore, are ontologically more basic than the thinking subject and all other Cartesian abstractions.
According to Heidegger, true thinking can take place only within the total relation of Being and man's nature. So Being and Time is simultaneously an analysis of our way of Being and an enquiry into the meaning of Being. Heidegger's approach to philosophical interpretation is based on his premise that when we philosophize we are attempting to reach a clearer understanding of something that is already vaguely familiar to us. So when he asks the question of Being he does so on the basis that we already understand Being in general, for it is this that allows us to raise questions about it.