“Man lives on nature – means that nature is his body, with which he must remain in continuous interchange if he is not to die. That man’s physical and spiritual life is linked to nature means simply that nature is linked to itself, for man is a part of nature.”
Karl Marx, “The Economic and Philosophical Manuscripts of 1844”
Heidegger descarta qualquer denominação do homem enquanto ser “racional”. Dizer que o homem é um “animal racional” é colocá-lo no mesmo nível de um ser-simplesmente-dado (present-at-hand: uma árvore, uma mesa, uma casa), pois atribuí-se uma “propriedade” ao Dasein. “Coisas” cujo “modo” de ser é simplesmente-dado precisam, para ser algo existente, de um “o-que”. Já o Dasein, enquanto única entidade cujo “ser” é uma questão, não.
“The essence of Dasein lies in its existence. Accordingly those characteristics which can be exhibited in this entity are not ‘properties’ present-at-hand of some entity which ‘looks’ so and so and is itself present-at-hand; they are in each case possible ways for it to be, and no more than that. All the Being-as-it-is [So-sein] which this entity possesses is primarily Being. So when we designate this entity with the term ‘Dasein’, we are expressing not its “what” (as if it were a table, house or tree) but its Being.”
Heidegger, “Being and time” (SZ, 42)
“If to interpret the meaning of being becomes our task, Dasein is not only the primary entity to be interrogated; it is also that entity which already comports itself, in its being, towards what we are asking about when we ask this question. But in that case the question of being is nothing other than the radicalization of an essential tendency-of-being which belongs to Dasein itself—the pre-ontological understanding of being.”
Heidegger, “Being and time”