海德格爾用此在呢個概念嚟表示笛卡爾同埋康德冇探索到關於存在嘅自然本性。由於啲人喺討論存在嗰陣時，一定會專稱某一個存在物，但存在嘅本身就隱而不露，所以我哋只係得到存在物嘅本身，而海德格爾就係一直追問存在嘅本質係咩。喺海德格爾角度睇嚟，我咃只有通過呢個方式去理解存在，先可以把握到存在嘅本質。海德格爾將此在定義為：期望、理解、把握、通達，呢啲都係構成存在嘅行為，而且佢哋本身就係一種特定存在者嘅模式，亦即係話，提問呢個問題嘅人向來都係某種存在者嘅存在樣式。所以要理解存在嘅本質就在於把握呢個提問者嘅存在。追問存在嘅本質呢個問題本身受到追問者嘅規定，亦係追問者存在嘅樣式，所以此在就係一種對存在發出追問嘅存在者。由於此在作為一種可以追問存在意義嘅存在者，所以它先可以成為我哋解決存在意義嘅特殊存在者。
Heidegger uses this concept to show that Descartes and Kant did not explore the natural nature of being. Since when people talk about being, they must refer to a certain being, but existence itself is hidden, so we only get the existence itself, and Heidegger always asks whether the essence of being is. From Heidegger's point of view, it is only through this way that I can grasp the essence of being. Heidegger defines this as expectation, understanding, grasping, and accessibility, all of which constitute the acts of being, and they themselves are a mode of a particular being, that is, the person who asks this question has always been a certain being's mode of being. So to understand the essence of existence is to grasp the existence of the questioner. The question of the nature of existence itself is regulated by the questioner, or the pattern of existence of the questioner, so it is a kind of being who asks about existence. Since this being is a kind of being that can question the meaning of existence, it can become a special being that we can solve the meaning of existence.