On the intrinsic belonging of possibility to the essence not merely of the animal, but of the living being in general, see in particular the 1929-30 course Die Grundbegriffe der Metaphysik: Welt—Endlichkeit—Einsamkeit. Gesamtausgabe Bd. 29/30. (Frankfurt: Klostermann, 1983). Translated by William McNeill & Nicholas Walker as The Fundamental Concepts of Metaphysics: World, Finitude, Solitude (Bloomington: Indiana University Press, 1995). Here it is once again a question of the actuality of possibility—the latter conceived as being capable (Fähigsein)—where possibility is not to be conceived as mere logical possibility and the actuality of possibility is not to be reduced to the actual deployment or actualization of such capability:
Correlative to this sense of being capable as intrinsic to the essence of life in general is the possibility of death and of being dead:
Once again, it is significant that Heidegger can here, at this level of the analysis, move back and forth, apparently seamlessly and unproblematically, between the animal and the essence of life in general; and where we can speak of the actuality of possibility as determinative of life in general, there we can also speak of death in general, of death as a possibility of life. Yet only apparently unproblematically: at another level of analysis, Heidegger will problematize precisely “whether death and death are the same in the case of man and animal,” thus whether life and life are the same, whether (the actuality of) possibility and possibility are the same (GA 29/30 388; Metaphysics 267). And Heidegger proceeds here to distinguish between “dying” (Sterben) as a possibility of the human being and “coming to an end” or “perishing” (Verenden) as the animal’s only possibility in relation to its death. At issue here, therefore, is ultimately the being of possibility, the way in which possibility “is” as a relation of being. Possibility, Heidegger will try to show (already in this 1929-30 course), can be given as possibility, as being possibility, only where there is logos, and only there can the possibility of impossibility be disclosed, thus, a relation to death as or in terms of possibility. The being of logos itself coincides with the thrown-projective character of Dasein, with its “irruption” into possibility, an irruption that ruptures possibility itself, quite literally takes it apart, dissects it, and only thereby is able to gather it as such. Here, we can only note in passing that this question of the being of possibility in relation to logos will be analyzed more incisively by Heidegger in the summer semester of 1931, in the course on the being and actuality of “force” or dynamis in relation to Aristotle’s analysis in Metaphysics Θ. See Aristotles, Metaphysik Θ 1-3: Von Wesen und Wirklichkeit der Kraft. Gesamtausgabe Bd. 33. (Frankfurt: Klostermann, 1990). Translated as Aristotle’s Metaphysics Θ 1-3: On the Essence and Actuality of Force, by Walter Brogan & Peter Warnek (Bloomington: Indiana University Press, 1995). We should note, furthermore, that Heidegger will maintain the distinction between “dying” (as a possibility of the human being) and “perishing” (as the possibility of the animal) throughout his later work, and ground this distinction in the phenomenon of the “as,” enabled by logos or the essence of language. For example, in the essay “Das Ding” (1950), where he writes: “(t)he mortals are the human beings. They are called mortals because they can die (sterben können). To die means: to be capable of death as death (den Tod als Tod vermögen). Only the human dies. The animal perishes,” In: Vorträge und Aufsätze (Pfullingen: Neske 1985), 171. Translated by Albert Hofstadter in Poetry, Language, Thought (New York: Harper & Row, 1971), 178. Or in the essay “Das Wesen der Sprache” (1957-58): “(m)ortals are those who can experience death as death. The animal is not capable of this. Yet the animal also cannot speak, The essential relationship between death and language flashes before us, but is as yet unthought.” In Unterwegs zur Sprache (Pfullingen: Neske, 1979), 215. Translated by Albert Hofstadter in On the Way to Language (New York: HarperCollins, 1982), 107. For an exploration of some of the stakes of this delimitation of the human from the animal see especially Jacques Derrida, De l’esprit (Paris: Galilée, 1987), and David Farrell Krell, Daimon Life: Heidegger and Life-Philosophy (Bloomington: Indiana University Press, 1992).