本文從「良知」的概念來探討海德格的倫理議題。我首先將「良知」視為一種對於匱乏或罪責去做補充的訴求，再將海德格強調存在性的良知置於「大地存有」的存有論層次，別於他所批評的可置於「文化世界」與認識論層次的世俗的良知。我並揭示出存在性的良知為存有對於此有的召喚，而這是對存有開顯有所匱乏或罪責的此有的召喚。惟此有之所以能讓存有召喚，正是因爲此有不再是個常人，不再自認為已經逃離了被拋以及沉淪所刻畫的現實性，並能夠簡單地往投企所刻畫的可能性去自由解脫。此有必須能自由敞開於罪責，不對現實性刻意的避開或忘卻，進而「讓」罪責顯現以至於能夠讓存有對此有召喚。這個論題是本文最關鍵之處。但為何這樣從存有論的立場可以談出倫理呢？我最後溯及西方形上學從探討存有過渡到探討人的存有，則開啟了道德底形上學的路數。鑑於此，海德格的倫理學可說從他對於西方傳統形上學解構又重構的形上學，因該形上學主要以人的此有為主題，故開啟了屬於海德格的道德或倫理底形上學。

This article discusses Heidegger’s ethical issues from the concept of “conscience.” I first regard “conscience” as a supplementary appeal to lack or guilt, and then place Heidegger’s emphasis on existential conscience on the ontological level of “Being of Earth,” which is different from what he criticizes can be placed on “Cultural World” and vulgar conscience at the epistemological level. I also reveal that existential conscience is the calling of Being to Dasein, and this is the calling of Being to Dasein that manifests its lack or guilt. But the reason why Dasein can be summoned by Being is precisely because Dasein is no longer “the ‘they’” (das Man), and no longer thinks that he has escaped from the facticity portrayed by being thrown and falling, and can simply go free to the possibility described by projection. Dasein must be able to freely open to the guilt, not deliberately avoid or forget the facticity, and then “let” the guilt appear so that Dasein can let Being call to Dasein. This topic is the most key point of this article. But why can we talk about ethics from the standpoint of ontology? In the end, I will trace the transition of Western metaphysics from the discussion of being in general to the discussion of human being, which opened up the path of metaphysics of morality. In view of this, Heidegger’s ethics can be said to be the metaphysics that he deconstructed and reconstructed from the Western traditional metaphysics. Because this metaphysics mainly takes human’s being as the theme, it opens up Heidegger’s metaphysics of morality or Ethics.