Heidegger pensa que a falha comum a praticamente todos os metafísicos é o fato de não terem colocado a questão do ser com suficiente rigor. Em particular, ignoraram as variedades de modos de ser, fixando-se antes num único modo de ser que aplicaram a todas as coisas que existem. Isto é especialmente problemático quando se trata do tema do fundamento de toda a ontologia — a analítica existencial que nos estuda.
Heidegger thinks that the flaw common to virtually all metaphysicians is that they didn’t ask the question of being rigorously enough. In particular, they ignored the varieties of ways to be, fixating instead on a single way of being which they applied to every thing that is. This is especially problematic when it comes to the subject of the foundation of all ontology – the existential analytic which studies us. The dominant thesis of Being and Time as we have it (we don’t know where Division 3 would have taken us) is that Dasein’s way of being is utterly unlike that of anything else, and the two divisions we have are an extended analysis of existence by constant contrast with two other modes of being. Heidegger repeatedly exhorts us to understand Dasein on and in its own terms rather than those borrowed from another kind of being. Let us call this demand the Existential Imperative. Metaphysicians have been seduced by a single idea and ideal of what it means to be – to participate in Forms, to be created by God, to be a substance, etc. – which they then force onto everything. Heidegger argues that the very fact that we treat, say, people differently from hammers or (18) rocks shows that we have at least a vague, pre-ontological appreciation of multiple ways to be. (p. 17-18)
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