Heidegger delivered this lecture in Freiburg on 31 January 1962. His first remark is that his lecture will not be immediately understandable, because it presupposes a mindfulness (Besinnung) of being, as such, and is not merely a treatise on the being of entities. We will need to linger, “while” or abide a long time, in the presencing of what is being said in order to understand its meaning.
Why does the title of the lecture bring time and being together? Heidegger shows first that in the history of philosophy, being means presence. Like the past and the future, presence is a characteristic of time. Being as presence is determined by time through the interplay of the temporal ecstases. This means that every entity comes and goes at the right time and in between abides during its allotted time. But is being a thing? Being is not a thing and therefore nothing temporary, or for that matter, eternal. And yet, it is determined as presence through the temporal dynamic of presencing. What about time? Time itself is neither a thing nor temporary, and yet it gives itself constantly or temporalizes. Although time and being are not entities, they determine each other.
In a second movement of thought, Heidegger remarks that time and being are both matters of thinking. It gives time and it gives being. Being itself gives the presencing of entities in revealment. At the beginning of Greek philosophy, being was thought not as that which gives, but as its gift, that is, the being of entities. The gift of being is its destiny and has its own history. Time is characterized from the present and being present means presence. Time is as now. In time, we are in the presence and self-manifestation of entities. Heidegger calls this the open, that is, time-space. In time-space, the future, having been, and the present play out their tension to yield presence and in this way reach each other in the clearing of openness. The unity of the three dimensions of time is grounded in their reaching each other, which brings them near to each. Times gives this nearness and enables us to be with entities and each other.
It gives being as gifting-refusal and as the destiny of presencing in its epochal changes. It gives time as the clearing, reaching of the four-dimensional realm of the open. Heidegger next asks what this “It” is that “It gives.” Does time give being and being time? Time and being belong together and this belonging together is the Ereignis that joins the gift of being with its simultaneous refusal. The “It” that gives time and being is the dynamic of Ereignis that preserves each through the other, and thereby allows time and being to come into their own. Heidegger ends this lecture with the remark that the elucidation of Ereignis is no longer the topic of his lecture.