This chapter defines the three spheres or forms of activity that Arendt takes as constitutive of our present human condition, our vita activa. The first is labor, which refers to the biological or organic processes of the human body that sustain our existence as a species. The second is work, the so-called “unnaturalness of human existence” by which we fashion a world of artificial things entirely distinct from our given, natural character (7). The third is action, which concerns the relationship between unique human individuals and therefore provides the necessary condition for political life. Arendt also refers to these three aspects of the human condition as life, worldliness, and plurality. 

All three of these dimensions of the vita activa are said to be “intimately connected with the most general condition of human existence: birth and death, natality and mortality” (8). Our vita activa is thus always oriented toward the maintenance and perpetuation of human life, whether in the simple sense of biological labor or the more complex processes of political action. 

Arendt concludes the chapter with an important proviso: The human condition should not be confused with the entirely different notion of human nature. To understand the latter, Arendt insists, would be to capture the eternal, unchanging essence of the human being in a manner analogous to the definition of a thing—a “what” and not a “who” (10). She states that only a god could do this, which is why all attempts to define human nature end in a kind of deification of the human being as an abstract idea or entity (11). 

By contrast, the question of the human condition concerns our status as “conditioned beings.” She elaborates: “Whatever touches or enters into a sustained relationship with human life assumes the character of a condition of human existence” (9). Her point is that everything that becomes an enduring or consistent feature of human life, whether natural or artificial, is transformed into a necessary component of our existence. In other words, human existence continually absorbs and reconfigures the elements of its situation and environment, placing them in relation to its natality and mortality. Unlike the idea of a static human nature, then, the conditions of human existence are persistent but not unalterable. If, for instance, human beings manage to find a way of living beyond the earth, the conditions of labor, work, and action would all radically change, but these extra-terrestrial creatures would still be human in some sense (10).

Chapter 2 examines the philosophical and historical genealogy of vita activa. Arendt traces the concept back to the beginning of the Western tradition in ancient Greece, particularly the trial and execution of Socrates, which, in a larger sense, represents the separation of philosophy from the polis or city-state (12). This event inaugurates a cleavage between the life of thought or rationality (vita contemplativa) and the life of action central to the operations of the political state (vita activa). After Socrates, action and contemplation are opposed, and the burdens of an engagement with politics and society are taken as inimical to the peaceful, detached life of the mind. 

Arendt goes on to examine the trajectory of this dichotomy between the vita contemplativa and the vita activa from ancient Greece to medieval Christian philosophy, touching on Plato, Aristotle, Augustine and Aquinas. The result is that vita activa became synonymous with the notion of askholk, the unquiet of worldly affairs that detracts from the possibility of unfettered, autonomous thought (15). From this view, action is a limit upon freedom, which is supposed to consist of rational thinking unencumbered by the necessities of the body and other people. While acknowledging this traditional opposition between vita contemplativa and vita activa, Arendt wants to reconstruct the concept.

This final chapter of Part 1 concludes the historical and philosophical reflections of Chapter 2. Arendt further explains the opposition between the vita activa and the vita contemplativa with a parallel distinction between immortality and eternity. 

For the Greeks before Socrates, immortality is tantamount to action, the performance of a famous deed or creation of a notable work that will outlive the individual and endure in a manner akin to the divine (18-19). This is what it means to be “the best” (19)—a hero, artist or athlete who is outlived by their actions is immortal, kept alive in the memory and esteem of a public or political society. 

Conversely, with Socrates, the competing concept of the eternal comes into prominence. Unlike immortality, which is connected to action, eternity is concerned with contemplation (20-21). The eternal is what is true or good, independent of the opinions or views of the public. Eternity is outside of the experiences of this world, a transcendence of the "here and now" more certain and inviolable than action. Christianity, with its message of salvation in heaven beyond earth, is a part of this tradition that values eternity over immortality. 

For Arendt, Western tradition has obscured the “striving for immortality which had originally been the spring and action of the vita activa” (21). Her aim in the remainder of The Human Condition is to bring it once more to light.