Thrownness, however, does not lie behind it as some event which has happened to Dasein, which has factually befallen and fallen loose from Dasein again; on the contrary, as long as Dasein is, Dasein, as care, is constantly its ‘that-it-is’.
This passage delivers the core ontological definition: thrownness is not a past biographical event but the permanent structural condition of Dasein’s factical Being, inseparable from care itself.
, Being and Time, 1962thesis